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i have a rampant esbl +ve cases problem in my hospital ,how do i control it? (answered 11/28/2006) |
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i am presently on klebsiella pneumoniae, i have taken all clinical isolates from different sources.its suceptibility by Disk diffusion test & MIC were performed.i am using different drugs including cephalosporins & Flouroquinolones.The mic values for gatifloxacine , o floxacine , Nalidixic acid , cefeclor , cefotoxime , ceftrixone are more tha 256 micrograms/ml .what may the posiible reason? it must be noted that majority of thaes are ESBL positive. Adnan Amin (answered 11/23/2006) |
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Please give me a concise synopsis of GISA, easy for students to remember. (answered 11/22/2006) |
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Hello, we are going to start using the E-Test method for susceptibility for S. maltophilia isolated on patient's cultures. We have elected to set up the Q.C. when we set up the patient test since we do not encounter S. maltophilia very often. My question is do we need to set up both E.coli and Ps. aeruginosa ATCC organisms or will using only one ATCC organism be sufficient for QC? The E-Test is very expensive and would like to see if I can be as cost efficient as possible and have the E-Test last as long as possible. Perhaps run both ATCC organsims for 5 days and if ok, then run E.coli after that with patient. Thank you, Elisa (answered 11/22/2006) |
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Is it unusual or not possible for Proteus mirabilis to be resistant to Cefoxitin? When a pure isolate tests as resistant is it appropriate to report as resistant? (answered 11/20/2006) |
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why is it not recommended to incubate transformation plates (E.coli) for more then 16-20 hours when selecting for ampicillin resistance (answered 11/13/2006) |
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can I trust ESBL vitek 1 ? shoul I confirm with Kirby-Bauer (answered 11/13/2006) |
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I have encountered a blood culture isolate of staph. aureus having the following properties: 1, it gives a zone size of OX1 from 11-14 & Cefoxitin zone size as 27mm on Muller Hinton agar; 2, it gives Etest MIC of OX as 1.5 (sensitive) and OX1 disc as 0mm zone size (resistant)on 2%NaCl Muller Hinton agar plate. The isolate is found to be MecA gene PCR negative but the isolate on 2%NaCl Muller Hinton agar is PBP2 latex positive. I want to ask if there is an induction of methicillin resistance; if there is discrepancy between MecA gene PCR result and PBP2 latex testing; what should I report this isolate: MRSA or MSSA? Thanks a lot! (answered 11/09/2006) |
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Should we be performing the D-test on the few staphs isolated from urine that we perform susceptibilities on? This doesn't happen often ( a few S. aureus and pure cultures of S. epidermidis from cath specimens). We do not normally report Clindamycin and Erythromycin on isolates from urine sources. (answered 11/09/2006) |
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I have encountered a blood culture isolate of staph. aureus having the following properties: 1, it gives a zone size of OX1 from 11-14 & Cefoxitin zone size as 27mm on Muller Hinton agar; 2, it gives Etest MIC of OX as 1.5 (sensitive) and OX1 disc as 0mm zone size (resistant)on 2%NaCl Muller Hinton agar plate. The isolate is found to be MecA gene PCR negative but the isolate on 2%NaCl Muller Hinton agar is PBP2 latex positive. I want to ask if there is an induction of methicillin resistance; if there is discrepancy between MecA gene PCR result and PBP2 latex testing; what should I report this isolate: MRSA or MSSA? Thanks a lot! (answered 11/09/2006) |
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The Culture and sensitivity of the sputum came back indicating that the MDR Pseudomonas aeruginosa is intermediate sensitive to cefepime. The physician insisted that it's alright to use cefepime to treat even it's intermediate. Please explain if this is correct. Thanks! (answered 11/08/2006) |
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Are there any guidelines that say a Proteus mirabilis that tests resistant to Cefoxitin should be confirmed or possibly reported as resistant? I found this in an old policy and cannot find anything to back it up. (answered 11/08/2006) |
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The local jail is frequently sending us swabs from boils that are positive for MRSA. They say that the patients are treated topically. How important is it to report MICs on these wounds? A majority of the time, they are already treated by the time we call them with the "critical result" of MRSA. (answered 11/07/2006) |
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When performing D Tests on purity plates, is the inoculum too diluted to give an accurate value? The final concentration tested isn't a .5 Mc Farland if we test from a prompt using Micrscan panels. Thanks (answered 11/07/2006) |
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The local jail is frequently sending us swabs from boils that are positive for MRSA. They say that the patients are treated topically. How important is it to report MICs on these wounds? A majority of the time, they are already treated by the time we call them with the "critical result" of MRSA. (answered 11/07/2006) |
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Is there a statement that can be put on reports about gallinarum/cassiflavus being intrinsically resistant to vancomycin? How should they be reported out when we get these organisms from the Vitek 2 analyzer and our sensitivity from the analyzer is verified and it is vanco I or R? (answered 11/01/2006) |
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We have a patient treated with imipenim for e.coli esbl uti.Subsequent urine culture grew pseudomonas cepacia resistant to imipenim but sensitive to tazocin.Hence patient was put on tazocin.Her urine culture still shows >100 thousand psedomonas cepacia.How can this be explained and treated ? (answered 10/23/2006) |
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in a esbl+ve strain is it necessary to test imipenem and meropenem separately? if so then why? (answered 10/19/2006) |
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We are concerned about false positives with disk ESBL confirmation method recommended by CLSI. There does not seem to be a way to easily recognize and distinguish AMP-C isolates from true ESBL-producing isolates. We cannot afford to put experimental tests into use. With this in mind, is there a clear way to distinguish AMP-C from ESBL by examining the organism's antibiogram? (answered 10/18/2006) |
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If a Staph aureus isolate is a high beta-lactamase producer and not a MRSA, can you get growth on the OX screen plate but have a Susceptible result for Oxacillin? (answered 10/16/2006) |
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We had an E coli tested on the Vitek2 that flagged positive for possible ESBL. It was resistant to Amp, Amp/Sul, Levo, and SXT. Intermediate to Cefazolin (16 mic). Ceftazidime and Ceftriaxone are /= 3 fold decrease in between the single drugs and the combination? Thank you (answered 10/12/2006) |
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Now that tigecycline is being used, what do you think of it? If the microbiology indicates that the bacteria is only sensitive to one of the tetracycline (ie minocycline), would you conclude that it's sensitive to tigecycline? If that's the case, which one would you recommend to use, tigecycline or tetracycline? I appreciate your comments. (answered 10/06/2006) |
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CAN AMIKACIN BE USED TO TREAT ESBL INFECTIONS IF IT SHOWS INVITRO SENSITIVITY? (answered 10/06/2006) |
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What is the recommended testing follow up for Coagulase Negative Staph and Vancomycin MIC Intermidiate and MIC Resistant Strains results from Automated system? (answered 10/05/2006) |
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When doing the Dtest for clindimycin does the zone have to have a blunt side or is there an indeterminate result possible when there is growth between the Clin disk and the Eryth disk,(when using a 0.5 Mcfarland dilution)? (answered 10/03/2006) |
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should we be reporting sensitivities to macrolides in staphs islated from urine? (answered 10/02/2006) |
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We have a Vitek 1, we isolated a Klebsiella pneumoniae ESBL positive on Vitek. We did the confirmatory testing using Ceftazidime/Ceftazidime-clavulanic and Cefotaxime/Cefotaxime-clavulanic. The test was negative for ESBL. Should I report this isolate out as ESBL negative and change the expert rules on Vitek so that the cephalosporins are susceptible? The expert rules change the cephalosporins regardless of MIC if the VItek ESBL is positive. (answered 09/13/2006) |
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Sould I test cephalosporin for staphylococcus? If not then why? (answered 09/13/2006) |
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ARE THERE RECOMMENDATIONS CONCERNING WHICH STAPH AUREUS ISOLATES SHOULD UNDERGO VANCOMYCIN SCREEN TESTING? CLINICAL ISOLATES OF STAPH AUREUS ONLY OR MRSA FROM MRSA SCREENING CULTURES ALSO? (answered 09/11/2006) |
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i have a pseudomonas isolate in my lab which is resistant to ceftizoxime,cefexime but sesitive to ceftazidime ,ceftriaxone so should i report it resistant to all or the way it is showing on plate? (answered 09/07/2006) |
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How often should the MIC for Enterococcus or Staphylococcus aureus isolates be repeated for inpatients from the same source? We currently repeat once a month. Gram negatives are repeated once a week. (answered 09/07/2006) |
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IS THERE ANY E TEST STRIPS AVAILABLE TO DETERMINE MIC FOR CEFOPERAZONE PLUS SULBACTAM 1:1 RATIO? (ANYWHERE IN THE WORLD) (answered 08/29/2006) |
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What is the recommended frequency of repeating mic's for Staph aureus and Enterococcus sp.? We currently repeat once a month and repeat gram negative rods once a week. thank you Alison Slymen (answered 08/29/2006) |
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Can you treat MRSA infection with vancomycin plus amikacin and expect synergy if the microbiology lab indicates MRSA is susceptible to gentamicin? Is MRSA in general susceptible to amikacin? Also any references recommended to read regarding this topic would be great! Thanks (answered 08/28/2006) |
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Is it possible that a VISA/VRSA could be missed by following the FDA vancomycin breakpoints vs CLSI breakpoints? We use a MicroScan. (answered 08/22/2006) |
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Hi, Our Vitek antibiotic suseptibility report for the last 12 months shows 99% of MRSA isolates (n=430) sensitive to gentamicin. This is not GM500 or High level gentamicin (HLG). I note that Sanford's Guide shows gentamicin as "not clinically effective" for MRSA. Should we supress the gentamicin results totally or warn to only use it in combination with another agent ? Thanks. (answered 08/19/2006) |
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What has to be done in order for our small hospital lab to validate a rapid strep test?Thank ypi (answered 07/31/2006) |
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HI! MY QUESTION IS : WE ARE CURRENTLY USING MICROSCAN PROMPT SYSTEM (BREAKPOINT COMBO PANELS). MY QUESTION HAS SEVERAL PARTS.THE FIRST QUESTION IS ON THE 30-ug CEFOXITIN DISC AND TESTING FOR MEC –A MEDIATED RESISTANCE IN STAPHYLOCOCCI.. THE WAY I AM READING CLSI STANDARDS IS WE NEED TO TEST ONLY COAGULASE NEGATIVE STAPHYLOCOCCUS (NOT STAPH EPIDERMIDIS) WITH CEFOTOXIN DISC FOR MEC A MEDIATED RESISTANCE. THAT STAPHYLOCOCCUS EPIDERMIDIS AND STAPHYLOCOCCUS AUREUS NEED NOT BE TESTED BECAUSE MICROSCAN MIC FOR OXACILLIN CORRELATES WITH THE PRESENCE OR ABSENCE OF THE GENE ENCODING METHICILLIN RESISTANCE (MecA). IS THIS CORRECT? MY SECOND QUESTION IS WHEN I START USING THE CEFOXITIN DISC I WILL NEED TO VALIDATE IT. DOES THIS MEAN TESTING IT FOR 20-30 DAYS USING STAPHYLOCOCCUS AUREUS ATCC 29213 OR DOES IT MEAN HAVING MY RESULTS DUPLICATED BY ANOTHER LABORATORY. IF IT IS THE LATTER OF THESE TWO HOW MANY RESULTS DO YOU HAVE TO HAVE DUPLICATED. I HAVE A FEELING I NEED TO DO BOTH OF THESE PROCEDURES. IF I HAVE TO DO THE 20-30 QC TESTING WOULD YOU PLEASE TELL ME IF THE NUMBER OF DAYS HAS CHANGED FROM 30 TO 20 AND WHEN THIS HAPPENED AND WHERE IT IS WRITTEN IN CLSI STANDARDS.. I THINK NEW YORK STATE REQUIRES US TO DO 30 DAYS. WHEN I PERFORM THE CEFOXITIN DISC PROCEDURE ON STAPHYLO- COCCUS DO I PERFORM IT USING THE STANDARD KIRBY BAUER METHODOLOGY AND THEN INTREPRET IT ACCORDING TO CLSI (M100-S16) PG 123 LAST QUESTION! IF I DO ALL MY STAPHYLOCOCCUS WITH CEFOXITIN THEN I WOULD BE ABLE TO ELIMINATE THE OX-6 PLATE. IS THIS WHAT MOST LABORATORIES ARE DOING NOW ? OR ARE THEY DOING JUST THE COAGULASE NEGATIVE STAPHYLOCOCCUS (NOT STAPHYLOCOCCUS EPIDERMIDIS) AND NOT STAPH AUREUS, WHEREBY YOU WOULD WANT TO KEEP THE OX-6 PLATE. AT OUR LABORATORY WE ONLY USE THE OX-6 PLATE FOR STAPH AUREUS TO CONFIRM MRSA. I KNOW OF SOME LABORATORIES THAT USE THE OX-6 PLATE FOR ALL STAPHYLOCOCCUS. IS THIS CORRECT? THANK YOU FOR YOUR HELP. (answered 07/30/2006) |
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In ESBL + strains,cefipime &Tazocin are very frequently susceptible,should we report them as such or always report as resistant? (answered 07/18/2006) |
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Do Pantoea sp produce AMPC Beta Lactamases? Should they be considered inherently resistant to Ampicillin, Coamoxiclav and First generation Cephalosporins as one would consider Enterobacter sp? (answered 07/17/2006) |
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what is the procedure and timelines for CLSI to publish breakpoints for an antibiotic with FDA breakpoints? (answered 07/07/2006) |
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Hi I don´t understand exactly how to report cefuroxime susceptibility. There is only one disk and 2 diferent breakpoints one for the axetil and other for sodic cefuroxime. It seems that you must include the two forms in the report? Usually the lab doesn´t knows what drug formulation the patient will recive (answered 07/06/2006) |
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When performing inoculum control competency, what is the acceptable range of colonies that should be present. CLSI states that there should be approx. 50 colonies, but what is acceptable as a reange? We have just started this, and are finding that we are ranging anywhere from 43-65 colonies. (answered 07/03/2006) |
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i want to know if clsi 2006 guidelines included that cefoxitin can be used alone for reporting mrsa isolates by disk diffusion without using oxacillin disks in the panel (answered 07/03/2006) |
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what is the important discs which we can use in antibiogram for ECOLI (answered 06/30/2006) |
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Recently we cultured Klebsiella pneumoniae from catheter blood, which had unusual susceptibility profile:amoxicillin R, cefazolin S, cefuroxime R. It was susceptible to third generation of cephalosporins, inhibitor combinations, other beta-lactams and other classes of antibiotics. ESBL screen negative.All above performed by disk diffusion method, according to CLSI gudelines.Repeated susceptibility testing: cephalothin R, cefazolin S, cefaclor S, cefaclor MIC 4mg/l, cefuroxime R, cefuroxime MIC 256 mg/l. (MIC determined by E test). The lab reported cefazolin as R. However, i could not find in the literature any explanation for high level R to cefuroxime only. Do you have an explanation? Have we reported cefazolin correctly? Thank you for your time (answered 06/28/2006) |
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Hello! Our lab is a small women's health lab and we are having difficulties finding a Proficiency test specifically for Group B Streptococcus antibiotic susceptibility. We use real time PCR to detect Group B Streptococcus during pregnancy. We have just begun doing Kirby Bauer sensitivities for a handful of physicians. Since GBS is the only bacteria we are set up to isolate, we feel we cannot subscribe to the general antibiotic susceptibility panels offered by CAP. Is there another agency who offers specific bacterial panels for this purpose? Is there another option for us to follow CLIA guidelines? (answered 06/15/2006) |
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When should Proteus mirabilis be tested for ESBL production? Should this be done routinely on all specimens? (answered 06/12/2006) |
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I have 2 questions regarding enterococci: We recently encountered a vancomycin intermediate E.faecium. Our infection control department questions whether this should be treated the same as a VRE for isolation purposes. What are others doing when this occurs? Also, intrinsically resistant enterococci (E.gallinarum, E.casseliflavus, E.flavescens) do not require the same isolation as a vanco resistant E.faecalis or E.faecium? (answered 06/06/2006) |
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Penicillin susceptibility testing for Group A & Group B streptococci is not necessary, but what about NOn-A, non-B beta hemolytic streptococci. I'm searching for an accurate comment to attach to reports to explain to the physicians just why they will not be getting susceptibility testing on all beta streptococci. thanks (answered 06/06/2006) |
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ceftazadime versus cefepime in P aeruginosa (answered 06/04/2006) |
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Our micro lab currently set up D-zone test on all Staph.aureus, but we only result a positive or negative result if the Erythromycin is resistant and the Clyndamycin is sensitive from our mic values from the MicroScan Walkaway. We do not give a result if the Erythromycin is sensitive or if the Erythromycin is resistant and the Clindamycin is resistant or intermidiate. When we have either of these mic results we report the D-zone test as not applicable. Is this the correct way to report the D-zone test? We currently have a physician who wants the D-zone test performed even when the Clindamycin is resistant or intermediate(Erythromycin being resistant). (answered 05/31/2006) |
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Is it necessary or helpful to perform routine susceptability testing on Haemophilus isolated from respiratory specimens? Is there helpful text information that can be added to the report to guide the physician in appropriate treatment? (answered 05/30/2006) |
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We performed KB sensitivities on an enterococcus and it was resistant to Pen-G. The tech (not sure why) peformed a beta-lactamse test using a nitrocefin disc. The beta-lactamse was negative. The KB was repeated and the isolate was sensitive. Had the Pen-G result not changed, should I have reported the isolate R or S to Pen-G? (answered 05/30/2006) |
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In 2004 we started doing the D-test. At that time there was no requirements to validate the test. Now CLSI recommends ATCC BAA-976 & 977 for test evaluation. Is it required for us to validate a test now which we have been reporting for 2 years? Thank you. (answered 05/26/2006) |
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Should you edit cephalothin to R if ampicillin is R? (for Enterobacteriaceae)I refer to David Livermore JAC, 2001, that it is not necessary to do it for C. diversus and Klebsiella, and also not in urine spc. And what to do if ampi is S, and cephalothin R according to the Vitek 2.? (answered 05/25/2006) |
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IF ON SENTIVITY PLATE ,IMIPENAM IS SENSITIVE,BUT MERPENAM IS RESISTANT AND CFOPERAZONE +SULBACTUM IS ALSO SENSITIVE SHOULD WE GIVE IT ie CEFOP.+SULBACTUM SESITIVE OR NOT -IN CASE OF ESBL+ ISOLATES (answered 05/25/2006) |
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What is the mechanism of resistance for Linezolid against Staph. Is it chromosomal or plasmid mediated. (answered 05/17/2006) |
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Can you suggest a procedure for adding 2% NaCl to broth macro dilution tests when testing Staphylococci and oxacillin? (answered 05/17/2006) |
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WHEN COMPILING ANTIBIOGRAMS USING THE LIS IS THERE A TIME FRAME TO EXCLUDE DUPLICATE ISOLATES. FOR EXAMPLE EVERY THREE DAYS FROM THE SAME SITE, SAME ISOLATE, SAME PATTERN? (answered 05/16/2006) |
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I see this question was asked in 2003, but was wondering if any type of screening for ESBL in patients that have previously been positive for ESBL has been developed since then. Would you perform a rectal culture, or culture the site of the past ESBL infection? Is there any commercial media available, or would we have to screen all E. coli and Klebsiella isolates present? This would be difficult to do from a stool culture. (answered 05/16/2006) |
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Please clarify a previous answer we received to a question posted 5/11/06. We are doing a 30 day QC study on cefoxitin with Staph Aureus ATCC 25923. We are getting a double zone around the disk. There is a distinct zone at about 32-35 mm (which is out of range) and a translucent zone at 23-26 (which is in the QC range). We have tried using a new QC org. and the disks are just opened; we have also used at least 2 different lots of MH and continue to get a double zone. We are also comparing it to a .5 McFarland Std before it is set up. The answer we got was to look at M100-S16 Table 3 because perhaps we are using the wrong QC S. aureus. We have been looking at M100-S16 pg 72 Table 3 where it lists the acceptable limit for QC strain Staph Aureus ATCC 25923 as 23-29mm. This table is for QC of disk diffusion which is what we are doing. Now we are really confused. Is it possible that S. aureus ATCC 25923 will have a double zone normally? Please clarify this for us. Thanks. (answered 05/15/2006) |
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Have disk diffusion ranges been standadized for colistin? (answered 05/14/2006) |
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Does CLSI recommend the new cut point for sensitivity test of Colistin? (answered 05/14/2006) |
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How often do I need to perform quality control for Kirby-Bauer testing? If we routinely do only a few KBs a year, can we perform QC at the time we do the patient testing or must we perform QC weekly? Thank you (answered 05/13/2006) |
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I have a question concerning ESBL isolates screened by the vitek2 expert system. Should a confirmatory be performed in this case ( I am using AST NO20 CARD).? If the anwer is positive ,can I perform an automated confirmatory test using a vitek2 test ,or should I confirm the mechnism by through a conventional method (CLSI RECOMENDED)? thank you sharon (answered 05/12/2006) |
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We have started doing a 30 day QC study on cefoxitin with Staph Aureus ATCC 25923. We are getting a double zone around the disk. There is a distinct zone at about 32-35 mm (which is out of range) and a translucent zone at 23-26 (which is in the QC range). We have tried using a new QC organism and the disks are just opened; we have also used at least 2 different lots of Meuller Hinton and continue to get a double zone. We are comparing the innoculum to a .5 McFarland Std before it is set up.We have dropped the disk on some patient samples and have gotten one distinct zone. Is the QC organism supposed to have this double zone? If not, what do you suggest next? Thanks for your help. (answered 05/11/2006) |
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CLSI has moved to make the Dtest mandatory for Staph. sps. Until recently we reported ER/CdR and ES/CdS routinely and suppressed the Clindamycin report when ER/CdS but texted the Dr. that he could request the Dtest should he need to prescribe Clindamycin. The Dtest is a manual off line test that will be incredibly time consuming for those of us with automated sustems. 50% of our isolates fit the ER/CdS profile, however 70% are inducible CdR. 30% of our ER/CdS Staphs are oxacillin sens and typically are only Pen and E resistant, ie, so sensitive Cd is not required. The CLSI requirement does not flow well(we are automated, Microscan) as well as increasing costs by adding this bill code to all Staph sensi's(we are NOT doing this for free!) Out of about 5,000 SA sensi's we had 11 requests for the Dtest. I understand that Clindamycin is an option for CA-MRSA but it seems like overkill to perform it and bill it for everyone as a "standard of care" on a Group B (optional to report) drug. In short, is this really a NCCLS must perform test? Particularly when it is a unrequested billable test performed on the basis of a NCCLS requirement? Additionally, if you have proved the potency of your E and Cd disks in your routine KB QC, what is the need for an additional organism to buy, maintain and run in our increasing Herculean QC regimen? I'm not sure what we would be checking for??Thank you for your time and knowledge. (answered 05/08/2006) |
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We have been asked to make sure our susceptibilities are valid for animals as well. In looking in the CLSI books, it appears that the breakpoints for gentamicin are different for humans and for animals. It mentions gentamicin breakpoints for Enterobacteriacae and for Pseudomonas. What about staphs? would gentamicin not be used on an animal for staph? or would those breakpoints be the same as for humans? (answered 05/04/2006) |
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When preparing an inoculum for susceptibility testing why can't you use the broth growth method for staphylococcus. (not recommended in CSLI guidelines)Does this mean all staph or just MRSA (answered 05/03/2006) |
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For Salmonella in extra-intestinal sites we have in our procedure to test nalidixic acid to verify our flouroquinolones (cipro and levo). However for children I understand that cipro and levo should not be routinely reported in this case? However recently one of our pediatric intensivists did request cipro and levo to be reported on a child. What is the recommendation and is there a reference for children. (answered 05/01/2006) |
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Does the CLSI recommend any one susceptibility testing method over another for both Acinetobacter and Stenotrophomonas sp. For example should Kirby Bauer be performed over Microscan( MIC method)? (answered 04/26/2006) |
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We currently cascade report antibiotics. If Ampicillin is susceptible, we do not report Amp/Sulbactam or Pip/Tazo; however, recently an ID doc has protested this behavior because she says her patients have underlying conditions and she wants inhibitor combinations even if Ampicillin is susceptible. Can you explain why she would need to use Amp/Sulb or Pip/tazo when Ampicillin is susceptible in a UTI for example? (answered 04/25/2006) |
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Can cefoxitin disk screen test be used alone for detecting MRSA, how can MRSA isolate be saved for later reseach? (thank you) (answered 04/25/2006) |
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IF bacteria undergo filamnetation upon administration of a drug is it incapable of further division or would it revive under favourable conditions. (answered 04/24/2006) |
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What is the relevance of testing for Augmentin in Entrococcal isolates if thay are resistant to Ampicillin. I have read that even though augmentin may be sensitive, it should at best be reported as resistant. (answered 04/20/2006) |
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How do I prepare discs of 30ug concentrations from 1gram of ceftriaxone powder? (answered 04/17/2006) |
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What is your opinion about reporting an Oxacillin resistant Staph epi. as MRSE? (answered 04/14/2006) |
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Are there new QC guidelines for the Dtest? There are new strains of S.aureus available that exhibit/do not exhibit the D zone. (answered 04/13/2006) |
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According to M100-S16 the AST for Enterococcus by the Kirby Bauer tecnique requires only the use of a Mueller-Hinton agar. In our laboratory we perform this assay in a Mueller-Hinton agar with 5% sheep blood like for S. pneumoniae. Is there any problem with that? (answered 04/13/2006) |
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What specimen types should be screened for ESBL production? (answered 04/10/2006) |
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We do the sensitivity of Staphylococcus using Vitek-2 and get the results in MIC, is it still needed to run the disc sensitivity test to check for clindamycin resistance by induction test? Please advise, Thanks. (answered 04/06/2006) |
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Can you suggest a reference for AST on eye cultures? (answered 04/04/2006) |
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Staph aureus ATCC 25923 is indicated as the only QC organism for quality control of the cefoxitin disk which we are using for screening of methiciilin resistance. What about Staph aureus ATCC 43300? Is there an established QC range for use with this organism? (answered 04/03/2006) |
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pg 64,CLSI DOC.M100-S16,JAN.2006.DO COMMENTS 2 AND 5 MEAN CEFOTAXIME MUST BE TESTED? SENTENCE SEEMS POORLY WORDED. THANK YOU. (answered 04/03/2006) |
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we have performed susceptability on a neqas isolate and was id enterocococcus fecium : Amp=res Pen resistant (PBP ) Vanco=resitant mic=32, teicoplanin =s mic 0.5 ,and High level genta =s . I was wondering if the high level sensitivity makes sense? thanks a lot. (answered 03/31/2006) |
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Can Acinetobacter spp. be susceptible to penicillin? (answered 03/31/2006) |
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Should both piperacillin and piperacillin/tazobactam be tested, results confirmed if susceptible and both reported for P. aeruginosa? We currently only report pip/tazo if piperacillin is resistant, but I am not sure this is correct. This was discussed but not resolved in a previous answer from 9/3/2003. In light of the new published study (Sader et al, JCM, Mar. 2006), we will begin confirming pip/tazo results but did not know if we should also confirm piperacillin. (answered 03/30/2006) |
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What is standerd for N.meningites Sencitivity ? (answered 03/30/2006) |
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We use disk diffusion for susceptibility testing. We use Cefoxitin as the indicator for oxacillin susceptibility for Staph. I've kept the oxacillin disk in our panel but am considering dropping it. We use the Cefoxitin results if it differs from the oxacillin for the methicillin resistance. I also have the techs streak the isolate on Methicillin Screening agar as a confirmation of methicillin resistance. Can I drop the oxacillin from the panel and/or the methicillin screening agar from our routine? What we are doing now seems like over-kill. (answered 03/29/2006) |
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I am resubmitting my question regarding the Vitek 2 and Pseudomonas aeruginosa testing Intermediate or Resistant to Cefepime yet Sensitive to Ceftazidime. I have reviewed the previous questions and found conflicting answers from 2003. One response is to report the actual results ...there is no precictable cross resistance. The other response states that the results should be comparable ... this pattern does not make sense. Our lab will repeat the card if requested but they do not confirm by an alternate method. Do you have any current information on this? (answered 03/14/2006) |
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When is Beta lactamase testing of enterococcus warranted? In CLSI M100-S15 pg 53 it states to perform a nitrocefin - based B-lactamase test on blood and CSF isolates. Wouldn't we want to test all Enterococcus isolates that were susceptible to Ampicillin? Thank you! (answered 03/06/2006) |
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What special conditions should be employed when performing antimicrobial susceptibility testing on staph aureus (answered 03/03/2006) |
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MRSA Screening- by using cefoxitin 30mcg disc & oxacillin 1mcg disc comparision shows discrepant results,for CoNS ( Cefoxitin sensitive, oxacillin resistant) Can you explain this. (answered 02/28/2006) |
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One of our Cardiologists on staff inquired about Acinetobacter baumanii acquiring multiple resistance. He said he had recently read and article on it. Are their any reports on this organism acquiring multiple resistance? (answered 02/21/2006) |
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hello, I received a phone call from a doctor, he was wondering why we reported a Staph aureus as a sesnsitive to SXT antiobiotic. He is saying that there is no Gram positive cocci that can be sensitive to this antibiotic. Can you please tell me if what he is saying is right? Thank you very much (answered 02/21/2006) |
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Is there a procedure for doing sensitivities on Gemella morbiollorum? (answered 02/15/2006) |
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Hi, We recently started validating the Cefoxitin disc for MRSA confirmation. We now have an isolate that was identified as S.aureus by Microscan, showed no growth on ox6 plate but had a double zone around the Cefoxitin disc (KB), a subpopulation and growth around the Cefoxitin disc. Further testing of the growth around the disc revealed that the subpopulation is indeed MRSA with the MIC value of >2 by Microscan. My question is whether Microscan prompt system is accurate method for MIC preparation inoculum? Has anyone had this experience before and how do you resolve it? Thanks (answered 02/12/2006) |
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why only klebsiellae pneumoea, klebsiellae oxytoca & E.coli,& not other Enterobactericiae are screened for ESBL production (answered 02/03/2006) |
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can i use disk difusion to test sensitivity for Pasteurella sp.? (answered 02/02/2006) |
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Is it possible for VREs to be susceptibile only to Pencillin and resistant all others: Ciprofloxacin, Gentamicin 500, Levofloxacin, Streptomycin 2000, and of course Vancomycin). (answered 01/25/2006) |
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Our facility is a rehabilitation facility. All of our patients come from other facilities and so have been on antibiotics therapy for some time. We have alot of ventilator patients sent to us in the hopes of weening them from the vent. That said we have MDR Acinetobacter on a regular basis. Our infection control doctor wants colistin tested on our MDR patients. I use the Kirby Bauer method and append a comment stating not CLSI standardized. The microdilution method which is preferrable is hard to find a facility that does these and is costly and time consuming. I see no breakpoints for disk diffusion for this organism/antibiotic in the new M100-S16 Acinetobacter section or QC disk diffusion section. What do you suggest I do if our infection control doctor still wants me to test this? Also is it necessary now to run both 25922 E.coli and 27853 P.aerug for Acinetobacter disk diffusion QC? Thank you. (answered 01/17/2006) |
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If oxacillin is sensitive (>19mm), can we report CEFTRIAXONE as sensitive by DISC DIFUSION for S. PNEUMONIA, and what are the limits for the zone diameters for cephalosporines (cetriaxone, cefuroxime, cefipime and ceftazidime) for this organism? (answered 01/11/2006) |
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I have recently had two K. pneumo that on vitek2 and KB and confirmed through a reference lab that were only sensitive to gentamycin. cefepime was also sensitive but was and ESBL. Can you give me any info on this. (answered 01/09/2006) |
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My husband has antimicrobial susceptibility, it is causing a cold like symptoms. He went to the doctor and the doctor gave him antibotics. What is the worst case in his situation. Can something really bad happen from this. We are not sure how it happened. (answered 01/04/2006) |
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I just attended the ICAAC meeting in D.C. where it was strongly suggested that labs test for Amp C in Enterobacteriaceae. How do we go about doing this? (answered 12/28/2005) |
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In an effort to get information to our physicians as quickly as possible we often set up identification and susceptibility tests on colonies as young as 10 hours old if they are big enough. I know there are problems with colonies that are older than 24 hours but what about colonies that are younger than 18 hours? (answered 12/28/2005) |
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Our laboratory is just started a new wound and soft tissue procedure,(ASM Clinical Microbiology Procedures Handbook) by using this procedure there are many culture in which Staph aureus grows and the gram stain has no wbc and no epi, therefore, no Susceptibilities are preformed. With the country's rise in community aquired MRSA we are feeling uncomforable with this. What is you opinion? (answered 12/20/2005) |
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Beta strep D-test: At what point is it positive if the zone is slightly resistant but not a complete "D". (answered 12/19/2005) |
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Is there a non-molecular method to detect metallo betalactamase? (answered 12/13/2005) |
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This year at SEACM a question was asked about how to do susceptibilities on CF patient's isolates. It was stated that susceptibilities should be done manually (by KIRBY BAUER) and not by automated means (ex. VITEK). Can you please refer me to an article or articles that states this fact. We would like to put this in practice. We are trying to write a procedure and need references to list. (answered 12/13/2005) |
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What is the standard turnaround time for a hospital lab to collect a urine sample, then incubate, indentify MRSA, and report this finding to a physician/RN? Is 48 hours acceptable? Is 72 hours acceptable? Who sets the standard/guideline? ASM? CLSI? thanks (answered 12/08/2005) |
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Why we should use oxacillin disc instead of penicillin disc in case of S. pneumonae while we are using penicillin disc with other streptococci to determine the penicillin sensitivity? what is the exact mechansim? Thanks (answered 12/08/2005) |
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Pantoea agglomerans susceptibility testing (answered 12/05/2005) |
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In referenct to AmpC isolates, is it necessary to isolate the patient as is the case with ESBL's? Also, is it possible to treat uncomplicated UTI's with Aztreonam and Cephalosporins if the isolate is resistant to these drugs in vitro? Thanks (answered 11/28/2005) |
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On the CAP Bacteriology Survey result form and also in the CAP Bacteriology Surveys Final Critique, Cefinase-2 is listed as method result for Beta-Lactamase testing. We currently use the BD Cefinase disk, but I am not familiar with Cefinase-2. I can not find it listed in product catalogs. Who is the manufacturer and how does it differ from the BD Cefinase? (answered 11/24/2005) |
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I have observed while performing the disc diffusion sensitivity for a pseudomons aeruginosa that,when the disc of imipenam was adjacent to ceftazidime the zone around ceftazidime bordering imipenam was flattened, how is this phenomenan explained? and would this imply that ceftazidime should be reported as resistant eventhough the zone size around ceftazidime would otherwise be reported as sensitive? (answered 11/23/2005) |
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Can you give the basics of reading a sensitivity report? Do you prescribe based on the lower or higher numbers in the report? Ex: <8 or < 32 ? Thanks! (answered 11/23/2005) |
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Can I test minocycline and colistin by Kirby Bauer methodology on Acinetobacter? I see zone diameters for Enterobacteriacea for QC and patients for Colistin but not Non-Enterobacteriacea. For Minocycline I see zone diameters for patients with Acinetobacter but the only QC zone diameters I see is for E.coli and not P. aerug. Can I test these two antibiotics using Enterobacteriacea QC and zone diameters when Acinetobacter fall into a Non-Enterobacteraciae catagory? (answered 11/14/2005) |
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Hi, I'm asking a question regarding vancomycin confirmations in relation to coag neg staph. The current CLSI M100-S15 states to send any staphylococci w/an mic of >-4 uf/ml to a reference lab for confirmation (comment 21 on table 2C). Does this statement refer to both S. aureus and coag neg staph? We do get a few coag neg staph w/ MICs of 4 that we currently confirm w/an alternative method, but this seems to be using valuable resources w/out a benefit to patient care. We have not had any S. aureus w/ vanc MICs of 4, but if we did, we would definitely send those out to our reference lab for confirmation. Any clarification on this issue would be greatly appreaciated! Thanks so much! (answered 11/09/2005) |
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With respect to Streptococcus agalactiae, page 67 of the CLSI 2005 guidelines states Rx: Recommendations for intrapartum prophylaxis for Group B streptococci are penicillin or ampicillin. While cefazolin is recommended for penicillin-allergic women at low risk for anaphylaxis, those at high risk for anaphylaxis may receive clindamycin or erythromycin. Group B streptococci are susceptible to ampicillin, penicillin, and cefazolin, but may be resistant to clindamycin and/or erythromycin. The infectious disease practitioners at our institution are questioning treatment of Streptococcus agalactiae with cefazolin. There have been 5 recent cases of systemic infection with this organism when cefazolin was used and apparent treatment failure occurred. They are questioning how has cefazolin been determined to be an active agent in treatment of infection if there are no CLSI guidelines for the laboratory . Are there documents, journal articles or studies stating the efficacy of cefazolin for use with Strep group B. (answered 11/09/2005) |
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It is recommended that susceptibilities be set on colonies that are 18-24 hrs. old. Is this a hard and fast rule or is there leeway one way or the other, meaning younger or older colonies and what are the ramifications? Could you also provide references? Thank you (answered 11/08/2005) |
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We are using microscan breakpoint panels. CLSI recommendations include the use of E. coli ATCC 35218 for testing antiboitics which contain clavulonate. However, the lowest dilution on the microscan gram negative breakpoint panel is 16 for TIM (the only Blactam/Blactam inhibitor combination that we report) This dilution is covered by E. coli ATCC 25922. Is it necessary for us to run the ATCC 35218 which would have a lower MIC? Along the same lines, is it necessary to run the E. coli 35218 with the gram postive panels for Aug? The use in this case would be to show growth in the single well. Is this required? (answered 11/08/2005) |
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Should susceptibilities be done on Micrococcus or Kocuria type organisms? (answered 11/07/2005) |
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The CLSI documents state that for reading Kirby Bauers you round to the nearest whole millimeter. Does that mean you use standard scientific rounding and anything 1.51-1.99 rounds up to 2, or does it mean you round to the nearest lower whole number ie. 1.51 = 1? (answered 11/06/2005) |
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Do all automated susceptibility testing methodes require confirmation of oxacillin resistance, vancomycin resistance, imipenem resistance, piperacillin/tazobactamresistance and/or cetazidime resistnace for Staphylococci species/aureus/lugdenensis;enterococci.staphylococcus species and Psuedomonas aeruginosa, respectively? (answered 11/01/2005) |
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our proteus mirabilis isolates and to a lesser extant e. coli, has shown resistance to ciprofloxacin and susceptible to levofloxacin. we have looked back, and since 2002, ourproteus isolates have shown thi sresistance pattern. We can repeatly see this pattern both on Vitek and by Kirby-Bauer testing. In light of CLSI guidelines, how should we report the quinilones? We are also looking into any reported clinical failure? Frequency of use with either drug (answered 10/31/2005) |
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Would it be appropriate to add a comment to patient reports from the literature i.e. Sanford Guide to Antimicrobial Therapy when organisms are detected in culture for which there is no standardized susceptibility method, e.g. Eikenella, Actinobacillus, etc. (answered 10/26/2005) |
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When testing for methicillin resistance in staphylococci using oxacillin disc 1mcg by Kirby-Bauer's disc diffusion method is it necessary to add 4% Nacl to the Mueller-Hinton agar? (answered 10/26/2005) |
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viridans strep intection of the cornea: what antibiotic drugs should be tested and which ones reported? (answered 10/25/2005) |
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linezolid Resistance in Staph, how does one report out a Staph aureus is an MIC >8? There are no interpretive standards for anything other than S. (answered 10/25/2005) |
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In regards to susceptibility tesing of Streptococcus spp. not pneumoniae, when should it be performed (e.g. specific sites or upon request)? (answered 10/25/2005) |
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Recently, In our laboratory,when we are detecting MRSA strains we find an unusual result. One Staphylococcus aureus isolate indicates Oxacillin-resistance but cefoxitin-susceptible. The repeat test result is still the same as previous. According to this result, how to report? MRSA or MSSA? Thank you! (answered 10/14/2005) |
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Is it correct that cefoxitin disks results take precedence over Microscan results in indicating oxacillin resistance or susceptibility? If so any isolate for which we see a discrepancy between the cefoxitin disk result and the Microscan result, we should defer to the results of the cefoxitin? (answered 10/13/2005) |
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Currently we are doing the cefoxitin disk diffusion test to indicate mecA-mediated resistance in Staph sp recovered from sterile sites (i.e., blood, tissue, joint, body fluid, etc) only. Should we do this routinely on staph recovered from non-sterile sites (i.e., urine, wounds, etc) as well? (answered 10/12/2005) |
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A patient who was cultured with a MRSA isolate was treated and subsequently cultured a Staph isolate that was sensitive to penicillin. A seperate patient with culture proven MRSA(confirmed) was then re-cultured 5 days later with a Staph aureus isolate sensitive to penicillin. Can you offer any explanations for the emergence of pencillin sensitive staph from a MRSA isolate? (answered 10/11/2005) |
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What ATCC strains are used with the cefoxitin disk when testing for the presence of the mecA gene. (answered 10/06/2005) |
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MDR - What is a good general working definition for multiple drug resistant organisms in the human clinical setting. Use a 250 bed acute care hospital for the setting. Thanks, Rick (answered 10/03/2005) |
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We are a small drug company developing a novel antibiotic using antisense technology. Is there an agreeded upon method for characterizing the MIC/MBC of novel or experimental antibiotics? Are the NCCLS/CLSI guidelines practical enough for the deterination of these values? (answered 10/01/2005) |
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Any figures on the number of hospital labs still routinely doing ox and vanco screens on S aurues and enterococcus? Also can you site the specific reference that requires performing vanco screens on S aureus? Thank you. (answered 09/29/2005) |
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Where can I find data on antimicrobial susceptibility patterns for E. coli in positive urine cultures? (answered 09/28/2005) |
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QC: When perfroming 20-30 day testing (as per CLSI/NCCLS)of a new antibiotic disk, how many ATCC strains should be set up. I'm looking for the minimum number of required strains. (answered 09/28/2005) |
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I want to know, how I should report an ESBL producing strain if we do not do the confirmatory test. We are not using the cefotaxime/clav.acid or ceftazidime/clavunalic acid disk. At present we are reporting the isolate as E.coli - probable ESBL. Is this the right way? Please guide me. Thankx for u r interest. (answered 09/25/2005) |
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In my research, I try to find mrsa colonization in healthcare workers. I tested S. aureus isolates with both oxacillin and cefoxitin disks (disk diffusion method). The same strain turns out to be sensitive to oxacillin but resistant to cefoxitin. I want to know which result is correct? (answered 09/15/2005) |
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We are making Telithromycin sensitivity results available from disk results, to complement our current Microscan panels. It is appropriate to report it for Staph and for Strep pneumoniae. After studying Tables 3 and 3A in CLSI, our question is: Do we QC the disk only with the QC Staph strain when we test it against a Staph organism? And test it against the QC Strep pneumo organism when the patient isolate is Strep pneumo? Or must both QC strains be tested each time we use the disk? Thanks. (answered 09/08/2005) |
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if ampicillin/sulbactam is sensitiveby KB on A. baumannii,shold we change it to resistant? (answered 09/08/2005) |
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I have been unsuccessful in locating documentation on when to refer an organisms susceptibility to another culture of the same type. Senior techs are in disagreement: some say it is 3 days due to acquired beta-lactam resistance, others state it is at the institutions discretion. What is the rule and where can I find it in writing? (answered 09/08/2005) |
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We currently use MicroScan MIC testing for S. aureus along with an oxacillin screen agar and oxacillin disk (for poss cefinase testing). Can we drop the mrsa screen agar if we choose to use the cefoxitin disk? Can we use the growth around the cefoxitin zone of inhib to test for cefinase? (answered 09/07/2005) |
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In previous NCCLS documents there was a notation that the automated systems are not reliable for Pseudomonas aeruginosa. The current CLSI standards do not make mention of this. Does CLSI recommend automated or the Kirby Bauer for Pseudomonas aeruginosa testing? (answered 08/30/2005) |
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SHOULD SUSCEPTIBILITIES ROUTINELY BE DONE FOR ALPHA HEMOLYTIC ORGANISMS ON ALL SOURCES OR JUST FOR BLOOD? (answered 08/16/2005) |
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1. When performing susceptibilities on Staphylococci by the Kirby Bauer method, the NCCLS/CLSI M2-A8 document says to read the oxacillin at 24 hours and that the "other agents CAN be read and reported at 16 - 18 hours". Can that be interpreted to mean that it is acceptable to read the "other agents" at 24 hours as well? 2. When using the cefoxitin disc to perform oxacillin KB susceptibilities on Staph, should the cefoxitin zone be read at 24 hours or 16/18? (answered 08/04/2005) |
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If on a Staph KB plate, the cefoxitin disc is susceptible but the oxacillin is resistant, should the oxacillin be reported as S or R? If on a Staph not aureus (not S. epi or S. lugdensis) the MIC is 0.05 but the PBP latex test is negative, should the oxacillin interpretation S or R? (answered 07/26/2005) |
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Are there any CLSI interp.'s available for testing Aerococcus sp.? (answered 07/25/2005) |
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The Cumitech 7B tells us to report all potential pathogens in sputum cultures, even if numbers don't support full workup. But when we report the presence of few or moderate Staph aureus, then the physicians want to know if it is MRSA. Since that amount is not considered significant, should we just stop reporting that particular "potential pathogen"? We are following the guidelines in the newest CMPH, along with the Cumitech. (answered 07/25/2005) |
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thank you for helping my Q is we got by vitek and disk diff. pseudomonas spp gentamicin , Amikacin resistant but Netilmicin sensitive ? (answered 07/22/2005) |
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Where can we find guidelines for how often to do susceptibility testing on an organism when it is being repeatedly isolated from a patient? Thanks. (answered 07/21/2005) |
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Is it possible to have a S. aureus that is oxacillin susceptible by a commercial MIC method, disk diffusion, oxacillin salt agar screen plate and a PBP2a assay but be positive for MecA by PCR (answered 07/13/2005) |
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We consistently get out of range (upper number)qc results with the ATCC strain of Haemophilus influenza for Ampicillin only. We follow the NCCLS procedure to the letter. Can you help us with this problem? (answered 07/12/2005) |
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We frequently receive swabs for culture from different superficial wound sites on the same patient. They usually grow Staph aureus, and this organism always has the same sensitivity pattern. Is it acceptable to do sensitivity testing on only one isolate, and report the other wound sites as "Staph aureus, call the micro lab if sensitivity testing is needed"? Would we be missing an MRSA in one site that might not be found in another? (answered 07/11/2005) |
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Concerning the testing of Penicillin and Cefotaxime on Streptococcus pneumoniae resistant to oxacillin. We got a problem in the differentiation of those S pneumo with MIC =2 OR MIC=4 because we are using Vitek 2 which issue results >= 2 ug/ml for Penicillin. We have tried the E test method but the results is not satisfactory as well. The NCCLS broth & agar dilution methods are quite tedious to follow. I hope to seek for other alternatives for the differentiation of these 2 categories. Pls advise. (answered 07/05/2005) |
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multidrug resistant acinetobacter treatment (answered 06/30/2005) |
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Should nitrofurantoin be reported on MRSA's from urine cultures? NCCLS/CLSI says to report Fd on urines for Staphylococci (no difference for MRSA). However, The Sanford Guide to Antimicrobial Therapy says it is not effective clinically (page 54). (answered 06/24/2005) |
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What is the recommended AST for Listeria and where can I find interpretive criteria? (answered 06/23/2005) |
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Currently we test all staphylococci by KB (dropping the CC &E for D-test) and cefoxitin to look for overcalling of oxacillin Resistance plus we do Vanc and MRSA screening agars. Upon reading the 2005 CLSI M100-S15 I ran across a comment/ Subcommittee Response on pg 162 "Testing of staphylococci against cefazolin and cefoxitin using an MIC method is not recommended. Determination of oxacillin susceptibility is best done with oxacillin when using an MIC method and by cefoxitin when doing disk diffusion. Does that mean I could go back to utilizing my Vitek and dropping the CC & E disks on the purity plate? second question we currently have not been doing any further confirmation of MRSA if the KB OX is R, the cefoxitin supports is <=19 S. aureus or <=24 for SC- and the ox screening plate is R then we call the organism an MRSA. Should we also be performing a test for mecA or PBP2a? (answered 06/21/2005) |
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Can Pseudomonas aeruginosa be resistant to imipenem and sensitive to ceftazidime? (answered 06/16/2005) |
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I have a question regarding cefazolin results. After reading some of the askit questions, it appears others are confused as well. We recently upgraded from the Vitek classic to the Vitek2. Our lab used to have a comment that would come up in our computer system when the cefazolin=s, but cefuroxime is I or R, it went like this, "If cefazolin is "s" but cefuroxime is 'I' or 'R', system will suppress cefazolin and unsupress cefphalothin (if available). In respone to calls:only cephalothin can be used as the class drug. If physician wants to use cefazolin itself, it will probably be effective. If he wants to use other 1st generations, cephalothin must be tested". Our lab no longer tests cephalothin. In this scenario, should we be changing our cefazolin from S to R or putting some type of report comment in to indicate that cefaz. is so beta-lactamase labile? (answered 06/15/2005) |
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A gentamicin and amikacin resistant, however, tobramycin sensitive gram-negative rod. Is this possible? Thanks. (answered 06/14/2005) |
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What is the standard inoculam size for MIC broth dilution metohd (answered 06/13/2005) |
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could you tell me about a refrence for performing mic with vancomycin for confirmation of vre detected by agar screen method (answered 06/12/2005) |
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We are seeing an unusual susceptibility pattern in an increasing number of Haemophilis parainfluenzae isolates recovered from our cystic fibrosis patients. Ampicillin zones are susceptible, but ceftriaxone is resistant. I understand that cephalosporins can be better inducers for resistance. Has this been documented in this organism? With regard to reporting, should ampicillin be resulted as resistant? These organisms are cefinase negative. Debbie Killingsworth University of Texas Health Center Tyler Department of Pathology - Microbiology B157 Microbiology Supervisor Phone: 903-877-5139 or 903-877-5745 Fax: 903-877-2816 deborah.killingsworth@uthct.edu (answered 05/26/2005) |
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recently we have recovered a rifampin resistant coagulase negative staphylococci from a catheter tip culture. It is the first rifampin resistant staphylococci at my institute in Los Angeles County. Is rafimpin resistance signifigant in the same manner as oxacillin resistances? Is rifampin resistnace just begining to appear in Southern California, or in the western states? Is the clinical outcome effected by this resistance? Rifampin resistnace was detected by Vitek and confirmed by Kirby-Bauer methode. Is there an ifection control isue that must be addressed? (answered 05/24/2005) |
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I started doing 30 day QC on cefoxitin with SA 25923. I'm getting a double zone around the disk. A distinct zone at about 32 - 35 mm and a translucent zone at 23 - 26. The 2nd meets QC. The 1st doesn't. Should it be this way? (answered 05/19/2005) |
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When incubating Staph for KB susceptibility testing, the recommended temp is 33-35 C. When routinely culturing specimens the recommended temp is 35-37 C. What is a way to handle this difference without having two different incubators set at different temp ranges? Thanks. (answered 05/18/2005) |
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After reading many of the Q&A regarding oxacillin vs. cefoxitin to determine MRSA, my question is this: Is it necessary, when setting up sensitivities on Staph aureus, to use both OX1 and FOX30 disks? I have previously told by my supervisor that the result of the FOX30 always determines whether or not I am dealing with MRSA. So I can't help but wonder why we continue to use the oxacillin disks. Any light that you shed on this subject is greatly appreciated. Karianne Hermanson, CLT (answered 05/17/2005) |
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i want to know the concentration of cefoxitin discs published in cdc fact sheet for detection of mrsa,or if you please send me the diametersfor interpreting cefoxitin disc diffusion using 30ug discs (answered 05/16/2005) |
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Should we be reporting Vitek ceftriaxone MIC results vs non Pseudomonas aeruginosa pseudomonas isolates? We currently suppress ceftriaxone vs Pseudomonas aeruginosa. (answered 05/11/2005) |
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We use CAZ30, CAZw/clav, CFT30 and CFTw/clav to confirm ESBLs. I have had instances where the zone size decreases with the addition of clavulanic acid. Is there another test I should be doing at this point? (answered 05/06/2005) |
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Direct susceptibility testing from blood cultures: Both of the microbiology laboratories where I work report the results of direct susceptibility testing (MicroScan) from positive blood cultures (BacTec and BacT/Alert). Both labs have performed verification studies of the technique of inoculating a 0.5 ml BHI broth with 4 or 5 drops from a positive blood culture bottle, and incubating 4-6 hours to achieve a stationary phase inoculum. Both labs use the RENOK to inoculate the dried MicroScan panels. Recently there was an incidence in which there was a discrepancy between the direct inoculum vs. standardized inoculum from isolated colony growth. Should the direct sensitivity procedure be discontinued? Is it sufficient to do a colony count on the inoculum? (answered 05/03/2005) |
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NCCLS M100-S14 says "penicillin resistant, oxacillin susceptible Staph strains are resistantant to penicillinase-labile penicillins but susceptible to other...etc". We have a physician that doesn't believe this is true 100% of the time and wants cephalosporin testing on all Staphs isolated from serious sites of infection. What references or articles can I give him to make him more comfortable with this guideline? (answered 05/03/2005) |
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We run MicroScan overnight gram positive panels for clinically significant coagulase negative staphylococci. Since data indicates that oxacillin mic's are not reliable for these organisms, we are trying to decide on which confirmatory method to use, and how to interpret results. We would prefer to use PBP2 rather then wait another day for cefoxitin disk diffusion. In either case, if the CNS tests resistant by the MIC and the confirmatory method is negative, should we report oxacillin as susceptible? Also is there any reason to worry about false susceptibility with the MIC method? (answered 05/01/2005) |
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We are finding a number of enteric isolates (predominantly E. coli) that are susceptible to cefazolin and intermediate or resistant to cefuroxime. We've been using the Vitek 2 system for the past two years (and didn't find any problems during our verification). The cefazolin MIC's are typically <= 4mcg/mL and the cefuroxime range is usually 8-16 mcg/mL (with some isolates >=32mcg/mL). Years ago we checked thes isolate, but the AES on the V2 does not flag them. I alsways thought if an isolate was susceptible to the 1st generation cephalosporins that one coul deduce susceptibility to the 2nd and 3rd generation cephalosporins. We are now seeing 10-20% less susceptibility to cefuroxime than cefazolin on our antibiogram. Biomerieux has sent me a feference describing cefuroxime resistance in E. coli due to changes in the outer membrane proteins but I haven't seen this described or explained anywhere else. I am currently saving E. coli isolates that fit this profile for an investigation. Is this a technical issue or are these isolates really less susceptible to cefuroxime? (answered 04/26/2005) |
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FOR ENTEROBACTERIACEAE CAN LEVOFLOXACIN BE USE AS AN INDICATOR OF THE PERFORMANCE OF GATIFLOXACIN (answered 04/19/2005) |
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What are the current NCCLS guidelines for susceptibility testing for viridans streptococci that are either intermediately or highly-resistant to penicillin? Are there consensus breakpoint MIC's for cephalosporins, and if so, by what test should the MIC's be ascertained? Thanks-- (answered 04/17/2005) |
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How do you interpret the susceptibility of AmpC positive
Enterobacteriaceae (especially Enterobacter cloacae) to beta lactam
antibiotics alone (especially cephalosporins of 4th generation) and to
beta lactam antibiotics combined with beta lactamases inhibitors? Does
standardized method for detection of these strains by disc diffusion
exist today (CLSI standards or other)? Thank you! |
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CAP survey Dec2004.Bacteriology.D-17.Pseudomonas mic was 8 which was Intermediate with the Vitek 2. The correct answer was supposed to be resistant. Any other Vitek 2 customers have the same result? It was suggested from another lab in town that all Intermediate mic results should be reported as resistant. Also should only interpretations without the MIC be reported to the Doctors. Thanks |
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cefoperazone & sulbactum has different ratios ie 1:1 and 2:1; which one
is correct, what is the correct ratio when sulbactum reduces the mic of
cefoperazone |
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What antibiotics should be tested for Strep pneumoniae? |
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We recently switched from K-B to Microscan. We will perform the D-test
on our purity plate. My reference says to QC with S aureus 25923. How do
I perform this QC? Will I have to keep MH plates for this or is there an
alternative way to perform the QC? I would rather not have to keep MH
plates in-house just for this. Also, what are the zone sizes? |
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We frequently isolate Brucella spp. from our patient population and are
looking for guidelines / references to help in the reporting of
susceptibilities for these isolates. Our physicians want susceptibility
results and are not satisfied with the reporting of MICs (Etest) without
interpretations of S,I,R. Having reviewed much literature we can only find
references to MIC90 values for various antibiotics, no clear category
interpretations for reporting; and there is significant discrepancy between
some of these MIC90 values. Any advice you can give on this matter would be
greatly appreciated. Thank you. Pat McWhinney |
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Is there a relation between MLS(B/c)and HLR-aminoglucosides resistency
in Enterococcus spp?I have observed statistical relation between these
two types of resistence.Please write me on iiosifov@yahoo.com |
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On a few E.coli isolates, we received an interpreation of sensitive or
intermediate for gentamycin and resistant for tobramycin. Should we
change the interpretation for gentamycin to resistant to match the
tobramycin result? |
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Is it OK to replace cephalothin with cefazolin as a representive of 1st
generation cephalosporins, since cefazolin is more active? Thanks!
|
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How often does one see synercid resistant enterococcus |
|
|
How are labs performing quality control on Mueller Hinton SB plates?
We're trying to follow the BD procedure but get Strep pneumo ATCC49619
zones that are too large. |
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|
Hello! In case of severe Listeria- or Strept. Group B-Infection the
therapy of choice is Ampicillin resp. Pen.G plus Gentamicin. When the
susceptibility testing suggests Genta is resistant, is there a
synergistic effect possible as it is in the therapy of enterococci? Or
is it useless to combine the drugs? Thanks a lot. |
|
|
Is there a published standard antibiotic resistance definition for gram
negative organisms? |
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|
I have a lab report from a dialysis patient ... source R nare....organism
#1 Staphylococcus aureus........and shows Oxacillin with MIC .>=8 and
states Resistant. The ARNP at work states that this does not mean this
is MRSA. The same lab also states Vancomycin MIC 16 and Resistant...she
says this is not significant either... that since it was the nares and
is still sensitive to some things (nitrofurantoin, rifampin and trimeth/sulfa
and was of the nares it is not significant... In a simple, easy to
understand way, can you tell me why it is not significant? She couldn't
be bothered to explain it to me. Thanks. |
|
|
Is it appropriate to report only a beta lactamase result on N.
meningitidis isolated from blood cultures? What other antibiotics may be
reported? |
|
|
According to our national committee, we are instructed not to report
results for azithromycin in nasopharyngeal Haemophilus influenzae
isolates. Can you comment on this? |
|
|
How do I consider an oxacillin diameter of 13mm and a cefoxitin diameter
of 30mm for a Staphylococcus saprophyticus |
|
|
when we encounter Stenotrophomonas maltophilia we test
trimethoprim-sulfamethoxazole via Etest strips. The equivalent MIC
breakpoint in NCCLS table 2B (Disk diffusion) states breakpoint of
>8/152 as resistant whereas table 2B for MIC has >4/76 as resistant.
Which would be the better value to use since Etest is somewhat dependant
on diffusion? |
|
|
I have a question regarding oxacillin testing in Staphylococcus sp. Is
it not recommended to use Mueller-Hinton with 2% salt when testing Staph
against oxacillin using E-test and if this is the case why is it
recommended to use plain Mueller-Hinton when using an oxacillin disc?
|
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ON MRSA ISOLATED WITH A SENS. ERYTHROMYCIN MIC DO WE STILL HAVE TO
PERFORM THE INDUCIBLE CLINDAMYCIN BEFORE REPORTING? |
|
|
D zone test should be to all staph. aureus regardless of the
susceptibilities to Erythromycin. Some say do d-zone only against
erythromycin resistant organism. I say the detection of inducible
clindamycin resistance can be determine regardless of erythromycin's
susceptibility test. We had a Clindamycin sens + erythromycin sensitive
Beta strep group b that was D-zone positive. So why can not staph.
aureus have the same inducible resistant. |
|
|
D
zone test should be to all staph. aureus regardless of the susceptibilities
to Erythromycin. Some say do d-zone only against erythromycin resistant
organism. I say the detection of inducible clindamycin resistance can be
determine regardless of erythromycin's susceptibility test. We had a
Clindamycin sens + erythromycin sensitive Beta strep group b that was D-zone
positive. So why can not staph. aureus have the same inducible resistant.
|
|
|
An institution I call on has recently decided to switch quinolones from
gatifloxacin to moxifloxacin. The micro lab is currently using Microscan
panel #B1014-347 (Microstrep plus 1), which contains levafloxacin and
gatifloxacin, but not moxifloxacin. They have asked me if they can use
gatifloxacin susceptibility results as a surrogate for determining
moxifloxacin susceptibilty with Strep. pneumo. rather than going to the
expense of changing Microscan panels. I am aware that moxifloxacin is on
Microscan gm+ panel #B1017-203, as well as on the gm- panel #B1017-309
and the combo panel #B1017-202. Is there any published support for
adopting this surrogate testing practice? Also, do you have a
recommendation for them that I can pass along? Thanks. |
|
|
After consulting with our Infectious Disease physicians and checking
other sources it appears that there would not be any reason to ever use
Clindamycin with an MRSA isolate and therefore we have dropped D-testing
for those isolates. Is this correct? What about methicillin resistant
coagulase negative staphylococci? We continue to perform D-testing on
those isolates but our references are contradictory on the efficacy of
clindamycin on these isolates. |
|
|
NCCLS AST guidelines have warnings in bold capital letters re reporting
1st and 2nd generation cepthalosporins and aminoglycosides as senisitive
when these agents are tested against salmonella and shigella. Do I do a
disservice to the patient and the physician if I continue to ignore
these warnings. Why would NCCLS make such a statment if it is not
important enough for quick protocol changes. |
|
|
For Pseudomonas aeruginosa, should the interpretation results for Imipenem
match piperacillin? |
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|
WE ARE PERFORMING GROUP B SCREENS USING LIM. WE PICK COLONIES, SUB FOR
ISOLATION AND USE A LATEX AG KIT TO CONFIRM THE GROUP B STREP. THEN WE
PERFOR SENSITIVITIES ON ALL GROUP B POS. IS THIS REALLY NECESSARY SINCE
I READ THAT THERE HAVE BEEN NO ISOLATES OF PENICILLIN RESISTANT GBS? THE
SAME QUESTION REGARDIN GROUP A STREP. |
|
|
Kirby-Bauer susceptibility testing on a coagulase negative staph from a
joint fluid was resistant to penicillin and ampicillin but susceptible
to oxacillin by cefoxitin disk. M.I.C. testing with oxacillin was
reported as 1; therefore, reported as Resistant to oxacillin. Both tests
were repeated with the same results. Could you please help us resolve
this discrepancy. |
|
|
at what measurement of zone of inhibition will you have a high degree of
sensitivity |
|
|
We have been performing QC testing on the Vitek GPS-110 card and all of
the recommended QC organism's MICs are within acceptable range for 20
consecutive days except E. coli ATCC#35218. Is it necessary to continue
to perform QC on the other QC organisms if they have been within the
acceptable range for 20 consecutive days? We have checked several new
isolates, some from frozen stock and others lyophilized that were
subcultured onto a blood agar plate, incubated for 24 hours (in
non-CO2)and placed in the refrigerator and used as our stock. (to be
used for 1 week only) We know that E.coli 35128 may loose beta-lactam
resistance plasmid. We have checked several different isolates (one from
another local hospital and one from Biomerieux)and it is still out. This
could go on indefinitely! What are your recommendations or suggestions?
Thank you for your help. |
|
|
One of our infectious disease docs has asked our micro lab if there is any
data to support testing piperacillin/tazobactam rather than piperacillin. Do
you have an answer to this? |
|
|
Can you help me with this problem: what criteria are used for excluding
copy isolates in computer statistics for purpose of doing cumulative
susceptibility reports? |
|
|
Why is an induced beta lactamase test not needed for Staphylococcus
species when susceptibility is done by disk diffusion method? |
|
|
The I.D. Physician in charge of our Micro department on occasion has
brought in a cartridge of discs of some new drug which was detailed to
him and caught his attention. Within a week or two he'll want us to test
it against the organism of a patient he's following just to see how it
works. This will happen 2-3 times at most and then we'll never hear
about the drug again. When questioned about the drug he'll say "keep the
discs around I may want to try them again". It rarely ever happens and
we end up discarding the expired cartridge with about 45 of the original
50 discs remaining. My questions concerns QC. Is it sufficient to
challenge the discs against the manufactures recommended QC organisms
each time we run a patient (ie: 2-3 times total) or is it necessary to
start the 20-30 consecutive day process when we get a request for the
first patient? Thank you for your help. |
|
|
If an enterobacter is cephalothin sensitivity on a vitek panel x2 is it
O.K. to sign it out as such or would it be better to override the
computer and call it resistant. The organism was Enterobacter gergoviae.
Thank you for your anticipated answer. |
|
|
We have just implemented screening of MRSA isolates for VISA/VRSA strains.
If we have a hospitalized patient with MRSA (vanco screen negative) who was
treated then recultured 5 days later and MRSA once again grew from the same
site, should the Vanco screen be repeated? In this case, the MRSA had an
identical susceptibility profile as the original isolate. What is the
protocol for frequency of Vanco screening of multiple identical MRSA
isolates from the same patient? |
|
|
I have discrepancy in sensibility results(S,R) of oxacillin(1μg) and
cefoxitin (30μg)disks in Coagulase-negative staphylococci(Disk
Diffusion).Which result should I consider as the correct one? Thank You.
|
|
|
I have a few product type questions: 1. Are there disposable dessicant/indicators
available? For use in a small ziplock for loose KB disks, ie for E-15
and CC-2 for D-test. 2. I ran across CO2 indicators in a catalog, should
I be using them in my CO2 jars and documenting this like I do anaerobic
indicators? Thanks |
|
|
Neisseria gonorrhoeae QC and penicillin zone size failure |
|
|
We use a Vitek for reporting our sensitivities. We were only reporting
S, I and R. Now we have been asked to provide the MICs because a few
providers want to see them. Should we be providing the NCCLS breakpoints
for each antibiotic on the report, specific for the organism or is that
overkill? |
|
|
When you get the MICs usually you show them as MIC 50 and 90. Why and
how do you pratically calculate the MIC 50 and 90? |
|
|
Is it necessary to be testing coagulase negative Staph as well as Staph.
aureus on vancomycin screening agar? Is it sufficient to be testing only
the Staph. aureus? Thank you. |
|
|
We use the Vitek system, which is set up to follow NCCLS guidelines for
MIC's, but when reporting a Salmonella sp, most MIC's report. Should we
be supressing most of these using CAR rules? If so, why aren't the NCCLS
guidelines in the software? Thanks |
|
|
Is it possible to get a list of new antibiotics introduced in 2004
|
|
|
Using Vitek, we have had the following results on several gram negative
rods: Ampicillin sensitive, Piperacillin and Piperacillin/Tazobactam
intermediate or resistant. Is this combination possible? Should we
always repeat the MICs? |
|
|
Microscan has told us that it is an approved method for testing and
reporting S. maltophillia -the debate comes not from the identification
but, the reporting of T/S- previously we reported that T/S was the drug
of choice but, not the actual sensitivity result. Then Microscan said we
could report out the actual breakpoint sensitivity, some of our techs do
not feel comfortable reporting the T/S. The NCCLS literature is a
confusing. Are there other drugs we should be reporting and is the
microscan reliable or is it a requirement to do disc diffusion.
|
|
|
Recently we have discrepent results with piperacillin, zozsyn,
cetazidime and imipenem between Vitek and Kirby-Bauer on Pseudomonas
aeruginosa. What is the best way to report susceptibilties in such a
case? I understand Tenover et. al has published a paper showing imipemen
discrepent results with automated testing. |
|
|
Does any one have a simple explaination for MIC that a lay person could
understand. Also an explaination the a MIC's for different antibiotics
are not interchangable. I have an individual that thinks if an
antibiotic has a "smaller number" that is one has a MIC of 16, and
another has a MIC of 8; that the "smaller number" is better. Please help
me clarify this. |
|
|
Is it valid to incubate Pen, Cefotaxime and Vancomycin E test
susceptibility for a microaerophilic strep anaerobically or in CO2?
|
|
|
Should Synercid be used to treat Enterococcus faecium? |
|
|
Should Daptomycin be tested against Enterococcus faecium? |
|
|
Are there any approved protocols for susceptibility testing of Eikenella?
If so what antibiotics are usually tested against this organism?
|
|
|
What is the correct thing to do when identifying Salmonella from a fecal
source- should the sensitivities be reported or not. We have not been
reporting the sensitivities and then we add a comment stating that it is
often not recommended to treat for gastrointestinal disease. NCCLS is
difficult to interpret- Are they saying that we should be reporting
sensitivities or if you are testing only test for those antibiotics
listed? Various techs at our institution read this differently.
|
|
|
We currently use Tryptic Soy broth to set up Kirby Bauer suceptibilities.
We also use the Vitek 2 for susceptibilities. The Vitek uses 0.45%
saline and we use that suspension to set up additional tests such as
d-test and and sxt disk. Clinical Micro. Procedure Handbook states to
use 0.9% saline. What is the affect of the difference in saline
concentration on susceptibility testing. I would like to get rid of Tsoy
and just use the Vitek saline setup to also do Kirby Bauers. Does this
change mean that I would have to redo the 30 days of testing on all the
antibiotic disks if I switch?? |
|
|
How can we differentiate between BORSA and MRSA? and can mecA gene be
present in a BORSA isolate which is sensitive to Amoxacillin clavulanic
acid? |
|
|
How critical is it to incubate vancomycin screen agar and oxacillin
screen agar plates for a full 24 hours? |
|
|
I would like to know if is posible to do the betalactamase (nitrocefin)
assay to test Pasteurella spp. for penicillin resistance. |
|
|
Can the Microscan dried panels be used for non-aeruginosa Pseudomonads
and other non-fermentative gnr's? Bailey and Scott's 11 edition (page
394) states that validated susceptibility testing methods do not exist
for these organisms, and that we risk giving out incorrect results.
Thanks for your help |
|
|
One of our clinicans believes that the hospital's annual antibiogram
should not reflect the testing done on our nursing home population
because it skews our data to the resistant side. The lab's concern is
that the antibiogram should also be representative of what's in the
community and many nursing home patients end up in the hospital. Is it
advisable to split the data into nursing home and non-nursing home or
would it be ok to put in a disclaimer stating that the data includes all
isolates tested (inpatients and outpatients)?. |
|
|
We were wondering whether or not we should be >reporting mic's on
Pseudomonas species, other than P. aeruginosa. The >11th edition of
Bailey and Scott states that reliable susceptibility >methods do not
exist for these slow growing organisms (i.e: Ps. >fluorescens, putida,
etc, and other non-fermenters), see page 394 >Bailey/Scott, 11th
edition. We had been doing a dried Microscan panel, >with 24 hour
incubation on these bugs (our usual MIC method is Vitek 1). > Can we
assume that if we don't have good growth in 24 hours on our >purity
check, that we should not be reporting the MIC? Is it safe to >assume
that if the purity check shows adequate growth at 24 hours, that >the
MIC is reliable? |
|
|
Can the results of susceptibility testing of cefixime predict the
sensitivity results of cefdiner for the Enterobacteriacea group?
|
|
|
I would like ask these questions about Serratia marcescens: a) What are
the mechanisms of resistance to 3rd and 4th cefalosporins and
carbapenem? 2) If the mechanisms of resistance is by plasmid - cromosome
or integron ? Thank you !!! |
|
|
What are the types of b-lactamases of Flavobacterium (or Chryseobacterium)
spp.? It seems to be susceptible to b-lactam/b-lactamase inhibitor
combination drugs e.g. Augmentin in disc diffusion test, though this's not
reliable. |
|
|
Keflex sensitivity MRSA |
|
|
Is it alright to use a .5 McFarland inoculum in .45% (Vitek) saline to
inoculate S.aureus to a Vanco Screen Agar plate? Thank you. |
|
|
We use the MicroScan and AutoScan system. If 30 QC has been run on both
instruments and deemed acceptable, is it necessary to run weekly QC on
BOTH instruments if the AutoScan is only used as a back-up when the
Walkaway is down. |
|
|
Does anbody know of any paper ,site giving resistance data on Aztreonam
|
| |
I am resubmitting the question regarding susceptibility testing of coagulase-negative staphylococci (CNS). I was asked by a clinician to test oxacillin-susceptible CNS isolate for cefazolin. The CNS was isolated from joint tissue. I told him that oxacillin-susceptible strains of staphylococci are susceptible to other penicillinase-stable penicillins, beta-lactam/beta-lactamase inhibitor combinations, cephems, and carbapenems;thus there is no need to test for cefazolin,and he can use it for treatment of CNS infection.The answer was based on the statement "k", pg 24 of NCCLS giudeline (M100-S14).Few days later, I found the following statement re susceptibility testing of CNS, in the same guideline (M100-S14), pg42: "For oxacillin-susceptible strains" (of CNS, but not S.aureus)"results for ...cephems, ...inhibitor combinations,and carbapenems, if tested, should be reported according to the results generated using routine interpretative criteria." I think these two statements are contradictory. Does it mean that oxacillin-susceptible CNS can be resistant (in vitro) to cephems, inhibitor combinations, or carbapenems?If so, does it mean we can not recommend them for treatment?In that case, susceptibility testing of oxa- suceptible CNS for above mentioned antibiotics should be compalsory, not optional ("if tested"). In the future, should I test significant oxa-susceptible CNS isolates for cephems, inhibitor combinations,and carbapenems, or should I just assume their susceptibility, according to pg 24?What is your advice? |
|
|
We currently perform Kirby bauer sensitivities on Pasturella isolates
(testing for; Ampicillin,Cefazolin, Gentamycin Tetracycline Amp/sublactam
Erythromycin Penicillin and Trimethoprim/sulfa. Is this the correct
methodology and are these antibiotics appropriate? Could we use Vitek?
|
|
|
At a seminar at ASM 2002 or 2003, it was said that when doing AST by KB,
you need to look at the Vanco zone of all SA at 24h for possible inner
colonies and that we need to set up all MRSA to a BHI-Va6 plate. Is this
still the current recommendations, or should ALL Staph (MRSA and MSSA)
be screened with BHI-Va6 in addition to the Vanco disk on our KB sensi?
|
|
|
S. aureus that is Clindamycin sensitive and Tetracycline resistant. Is
it a community associated strain or a traditional MRSA? |
|
|
What is the difference between penicillin resistant S. Peneumonia strains
and methicillin s. aureus ones? I thought that methicillin resistance
described resistance to penicillin. Thank you in advance. |
|
|
How to storage antimicrobial disk? |
|
|
We currently detect ESBLs (Ecoli and Klebsiella) using the Vitek. We have
been asked to test Serratia, Enterobacter, and Pseudomonas for ESBL
production. The NCCLS procedure is only recommended for Ecoli and Klebsiella.
Any suggestions as to how we can do this? |
|
|
with respect to multi-drug resistance and antibiotics, why would it be said
that using a antibiotic to treat a viral infection leads to antibiotic
resistance with respect to bacteria. If there is no bacteria (only a virus)
how does the antibiotic get the opportunity to mutate or change a pathogenic
bacteria. Where is there an encounter? |
|
|
CDC has recommended suplementing MIC testing for vancomycin susceptibilites
on staphylococci by using BHI-V agar. This media is not validated for
staphylococci and its use is not supported by manufacturers. Is there any
data supporting the efficacy of BHI-V to determine vanocmycin resistance in
staphylococci? |
|
|
When performing the D-test on S.aureus for Clindamycin and Erythromycin, one
of the methods suggested is to use the purity plate from a Vitek setup. It
says to inoculate a BAP agar plate. Is BAP OK or does it need to be a
MuellerHinton agar plate if you're dropping antibiotic disc? |
|
|
Is it acceptable to set up enterococci on Vancomycin Screen agar(BBL) using
Vitek saline(BBL 0.45%) instead of physiological saline(.9%) to make the 0.5
McFarland? |
|
|
What is the recommendation to treat MRSA infection: Vancomycin alone or in
combination with rifampicin/gentamicin? |
|
|
We currently use Microscan panels for id and susceptibility testing of Staph
aureus and coag neg species of Staph. We are considering addition of the
Disk Difusion Screening Test using 30 mcg cefoxitin disks. Will comination
of these two tests be sufficient for predicting methicillin resistance in
Staph sp both coag positive and negative. Also, can the disk be dropped in
the first quadrant of the purity plate used when setting up Microscan
panels? |
|
|
Is it write gentamicin resistant staphs shoud be resistant to all
aminoglycosides? |
|
|
If citrobacter freundii is resistant to cefazolin is it an ESBL? |
|
|
Has anyone isolated a strange colony variant of E.coli on a MacConkey agar
that appears to be a nonlactose fermenter with one or 2 "dots" of lactose
fermenters that appear as "colonies within a colony"? I am able to isolate
the pink areas of the colony, and find that the susceptibilities between the
nonlactose fermenter and lactose fermenter are different. I don't mean mixed
colonies on top of one another, I mean one well-isolated colony with pink
pinpoint dots within the nonlactose or "clear" colonies? |
|
|
How reliable is a culture for resistant organisms if the patient is
currently on antibiotics? |
|
What
would be a standard recommended amount of time to wait after antibiotic
treatment until a repeat culture is considered valid? This would vary
according to the antibiotic and site of infection? |
|
I
have a couple of questions regarding susceptibility testing. The general
recommendation that I have heard is that isolates from sterile sites
should have susceptibility testing performed every 24 hours, and isolates
from other sites, such as sputum, wounds, etc., should have susceptibility
testing repeated every 3-4 days. 1. For the "other" sites, when
a sensitivity does not need to be performed, what degree of identification
is required to confirm that the organism is the same as was previous
reported? For example, should you do an API on a gnr to confirm that it
really is a Kleb pneumo as reported on a previous culture, or can it be
reported using a descriptive ID such as "probable Kleb pneumo"?
2. What constitutes the same site? For example, would big toe left foot,
and little toe left foot be considered as the same site? They are
different sites, but are in the same area. I know this is picky, but I
want to be sure that we are not over-working or under-working the
cultures. |
|
Is
a validation study required for the use of Oxacillin-Salt Agar and BHI
Agar with 6ug/ml of Vancomycin if daily quality control is performed? If
yes, do you have any recommendations? |
|
We
have just switched panels on Vitek to GNS-143. Previously, an expert rule
fired that prompted to change the Cefazolin to Intermediate (on E.coli) if
the Ampicilln was resistant, the Ampicillin/sulbactam was intermediate or
resistant and the Cefazolin was sensitive IF the carboxypenicillins or
ureidopenicillins were >S. This was due to a probable acquired beta-lactamase.
On our new panels, we do not have a carboxypenicillin or a
ureidopenicillin, so the rule will never fire. I am concerned that we will
miss these acquired beta-lactamase producers on our new panel, thus
falsely reporting a sensitive Cefazolin result. Any suggestions on how to
pick-up this possible resistance? |
|
Does
it make sense to perform the ESBL confirmatory test on an isolate of E.
coli or Klebsiella, which shows a positive screening test for ESBL but is
full resistant to amoxicillin-clavulanic acid (no inhibition zone in the
Kirby-Bauer test)? If an ESBL isolate can be amoxicillin-clavulanic acid
full resistant, how often does it occur? |
|
dtest-
Is it necessary to do 20-30 days QC with inhouse positive and negative
controls before going to weekly testing? The disks are already qc'd weekly
w/ S. pneumoniae on MHSB for testing against Group B Strep. |
|
I
want to add media as backup to Microscan for MRSA, VISA and VRSA. We use
Mannitor Salt/Oxacillin for our MRSA screen cultures. Is this media
acceptable to use for susceptibility back up or should we use MH oxacillin?
The package insert for BHI vanco says QC should be performed each time a
susceptibility test is performed or weekly if satisfactory performance can
be documented according to NCCLS. (I assume this applies to the MH
oxacillin, would it apply to the Mannitol Salt oxacillin? Presently we
only do QC on mannitol salt oxacillin on each new lot/shipment. |
|
When
setting up the D-test one of the suggested procedures is to use the Vitek
purity plate, which would be a blood agar plate. Is this acceptable media
or should it be a Mueller-Hinton agar if you are dropping antibiotic
discs? |
|
Regarding
susceptibility testing of both gram positive and gram negative organisms,
what type of media should be used for inoculum growth in preparation for
MIC testing? I am asking this question since NCCLS says a non-selective
media should be used and the manufacturer says non-inhibitory agar should
be used. What is the definition of a selective medium and an inhibitory
medium. |
|
We
are attempting to create a QC procedure for inoculum suspensions for MIC
testing. The NCCLS (7.3.1, pg 16) and the AB BIODISK package insert are
different enough to cause confusion. Can you please recommend a basic
procedure using "ul" as units and provide a colony count range
("approximately 50 colonies" given by NCCLS is vague). I |
|
We
do QC weekly for Erythro, Clindamycin and Oxacillin on MHSB w/ S pneumo
ATCC 49619. I read that S. aureus is a better indicator of disk potency
for oxacillin. If we decide to use S aureus for oxacillin QC, i assume we
have to do 20 consecutive days before switiching to weekly. We only use
oxacillin disks for testing with S pneumo isolates. |
|
In
the 2004 NCCLS it is recommended to test Salmonella isolates for
fluoroquinolone resistance by testing with Nalidixic Acid. This is
mentioned for extraintestinal isolates. What if anything should be done
with fluoroquinoline S nalidixic acid R isolates from stool isolates? |
|
Are
there any articles or studies that i can refer to that supports the NCCLS
statement that individual hospitals should test for ESBL's in urines? Also
you answered a question about using organisms growing on CNA agar for
MIC's on the MIcroscan saying that there was no limitations against it. I
spoke with the technical staff and they recommended not using isolates
from this agar for MIC's. I was wondering if there are any references on
your answer. You answered this question on 4/29/04. |
|
Do
you recommend to test Cefoperazone+Sulbactum against Gram Negative bugs.
Is this combination enlisted on FDA approved list. Thanking you in
anticipation and Looking forward to hear from you soon. |
|
Could
someone explain the rational behind performing 20 - 30 day testing on new
antibiotics. We are CAP accredited and the checklist state we must perform
this 20 -30 day testing intitially and then we can perform weekly QC
testing instead of QC testing with each patient. OK, but why the 20 -30
days of testing? I can understand the need for weekly QC but not the
initial 20-30 days. Is this requirement ever going to be done away with or
will the number of days be reduced again? |
|
We
have been made aware of inducible clindamycin resistance in all Staph.
species. This can occur if the Staph is erythromycin resistant and
clindamycin sensitive. I am looking for information about the D-zone test.
Please tell me what you know about this. |
|
This
question concerns inducible Clindamycin resistance. If the organism is
resistant to Erythromycin, you wouldn't use Erythromycin, so Clindamycin
resistance could not be induced. Therefore, please tell me why I'm doing a
special test for this??! |
|
I
need to know how a heavy inoculum would affect the results when using a
Kirby-Bauer medium. |
|
We
use Vitek for our Pseudomonas sensitivities, but I know that there are
different opinions about whether or not to do Kirby Bauer or Etest. Would
you please comment. Also would you comment on which method is recommended
for other gram negative non-fermenters. |
|
What
is the standard amount of time recommended to awit after antibiotic
treatment is ended until a repeat culture is considered valid? |
|
Can
organisms growing on CNA plate,like staph or enterococcus, be used for AST
on instrument like Vitek or Microscan? |
|
I
have read alot on the division C discussion group site about the alleged
inability of automated susceptibility testing systems to detect VISA and
VRSA. We use Vitek 1 as our primary susceptibility testing system. We
automatically sub our Staph aureus isolates to an oxacillin plate to
confirm MRSA although it's been years since we have had a discrepancy.
Should we planting all our Staphs on a Vancomycin plate as well to confirm
that we don't have a vancomycin intermediate or resistant Staph? |
|
We
are frequently requested to test MRSA, Staph aureus and Enterococcus
isolates against daptomycin. The M100-S14 guideline has QC ranges for this
antimicrobial agent but no breakpoints for testing patient isolates. How
would you report this drug on a patient report, i.e., what if any
disclaimer statement would you include? We are currently giving a verbal
"off-the-record" result to the physician using zone diameter
interpretations from the package insert. Can we technically report this
drug without NCCLS zone diameter interpretive standards? |
|
According
to the MIC interpretations standards on pg 124 of NCCLS Table 2H under
"Incubation conditions", it states that "incubation may be
in CO2 if necessary for growth." My question is does an organism that
was incubated in such a condition (CO2) to obtain sensitivities require a
disclaimer or statement that CO2 enhancement incubation was utilized? |
|
Is
it acceptable to perform disk susceptibility testing on Haemophilus sp.
other than Haemophilus influenzae from sterile body sites? What would be
appropriate drugs to test from these sites? |
|
Knowing
that a laboratory should validate a procedure before implementing it, what
is the "gold standard" that is being used to validate the
"D" test? Is the only solution a molecular study to determine
the presence or absence of the "erm" gene? Or do institutions
just implement the procedure without validation? Which option would NCCLS/CAP
support? |
|
How
do clinical micro labs separate out duplicate isolates for susceptibility
reporting. According to NCCLS M39A, duplicates should not be reported, as
they will skey the data. Is separation of the MICs done manually or is
there lab software that can perform the function? |
|
If
I read M100-S14 correctly, there is no approved way to perform
susceptibility testing on Pasteurella, Vibrio other than cholera or
Aeromonas. Is that correct? |
|
CURRENTLY
THERE ARE INTERPRETIVE GUIDELINES FOR THE RAPIDLY GROWING MYCOBACTERIA BY
BROTH MICRODILUTION . CAN THESE GUIDELINES BE USED FOR THE ETEST METHOD |
|
What
are ASM treatment guidelines for CAP, for ABECB, for Pharyngitis/Tonsillitis,
for Skin Infections? |
|
When
the same isolate is recovered from different sites, all collected within
1-2 days from each other, is it acceptable to perform only one
susceptibility and refer the other cultures to the first culture. For
example: S. auerus is isolated from wound, urine, and blood cultures. The
wound culture was submitted first and so the susceptibility was performed
on this site, later S. auerus was isolated from the other cultures. Is one
susceptibility acceptable or would you recommend susceptibilities be done
on all isolates. |
|
Regarding
aminoglycoside AST and hierarchy: If repeat testing has confirmed a
gentamicin susceptible, tobramycin resistant GNR (either Pseudomonas or
Enterobacteriaceae), should the MIC and NCCLS interpts be reported as
tested or should the results be overridden? (ie, report tobramycin as
resistant even though the MIC was susceptible?) |
|
NCCLS
GUIDELINES FOR PROPIONIBACTERIUM SP |
|
do
you have any information on hetero-resistance in organisms, especially
coag negative staph? |
|
In
order to restrict reporting of 2nd and 3rd generation cephalosporins, our
laboratory will allow reporting only if gram negative Enterobacteriaceae
is intermediate or resistant to cefazolin. NCCLS M100-S13(M7) p.21 2003
states "Cephalothin can be used to predict activity of cephalothin,
cephapirin, cephradine, cephalexin, cefaclor, and cefadroxil. Cefazolin,
cefuroxime, cefpodoxime, cefprozil, and loracarbef (urine isolates only)
may be tested individually because some isolates may bne susceptible to
these agents when resistant to cephalothin." Should we be using
cephalothin instead of cefazolin as a rule if I or R to unsuppress 2nd and
3rd generation cephalosporins? |
|
This
question is related to the frequency of processing specimens for culture
and sensitivity: What are accepted guidelines for the submission of repeat
specimens from the same site on the same patient for C&S? Case in
point: We have 2 physicians who will repeat Bronch Washes on the same
patient as many as 5 times on consecutive days and request C&S on all
5 specimens. At my previous institution, we would not accept a
"repeat" culture on the same patient/same site while a previous
specimen was still in progress (essentially every 48 hours). I am speaking
here of routine urine, lower respiratory, stool, wounds, etc. I am not
referring to surgical sites, blood cultures, and such. |
|
I
could not find breakpoint/ interpretive criteria for MIC testing of gram
positive anaerobes to vancomycin in the NCCLS M11-A5 document,
(particularly w.r.t. C. difficile. ) Also I wanted to find out if brucella
blood agar is equivalent to Wilkins Chalgren or WC blood for vancomycin
MIC testing in case of gram pos anaerobes? In footnote b for Table 2,
these media are considered equivalent for metronidazole MIC testing. |
|
Can
we report a sensitive clindamycin if the erythromycin is sensitive? The
microscan does not send the clindamycin across if the erythromycin is
sensitive. |
|
REGARDING
CLINDAMYCIN D TEST:Is 15mm apart for erythro and clinda disks correct?
Also disc content: is erythro 15 ug/ml and clinda 2 ug/ml correct? I heard
Hindler and Tenover at ASM. How can I contact J. Hindler to learn more
about "Clinda D Test". |
|
On
Staphylococcus sp. is it possible to have a Clindamycin Resistant,
Erythromycin Susceptible isolate? What about Streptococcus pneumoniae and
other Streptococcus species? |
|
I
have 2 questions: 1. Should Enterobacteriaceae, non-Enterobacteriaceae
interps, or neither be used when performing susceptibiities on Aeromonas
species. 2. NCCLS document M100-S13 (M7) gives susceptibility guidelines
for "Haemophilus sp.". I would like to verify that a cefotaxime
or ceftriaxone non-susceptible result would be atypical for all species of
Haemophilus, and not just H. flu. I've seen some publications that say it
is only H. flu. |
|
what
are the effects of agar depth, inoculum size,and cations on antibiotics
inhibition zone |
|
Can
you explain how to find an MIC50 and MIC90? |
|
When
perfoming the double disc diffusion ESBL confirmatory test, is there a
standard distance (ex. 15mm)that the discs must be apart? |
|
How
many colony-forming units are there in 0.5 McFarland? |
|
What
exactly is MIc 90? |
|
I
have been asked to develop an ESBL screening procedure (for E.coli and K.
pneumoniae) for a nursing home chain that seems to have a predominance of
ESBL infections. What cost-effective methodolgy, including sites to be
cultured, planting media and antibiotic disks, would you recommend? I
would like the turnaround time to be as quick as possible. |
|
I
have been trying to get the new NCCLS guidelines for the agar disk
diffusion technique for Staphylococcus species. It's not available in the
Library. I am a postgraduate student in South Africa. |
|
Our
pathologist has asked for a reference that supports the comment we use for
penicillin-intermediate Strep. pneumoniae- i.e., that penicillin may be
used at a higher dose for pneumococcal pneumonia, but not for pneumococcal
meningitis. Can you help with a lawyer-approved reference regarding the
inappropriate use of penicillin on patients with penicillin-intermediate
pneumococcal meningitis? |
|
I
am preparing a 400 mcg/ml antibiotic stock solution. Where can I find out
if what I did is correct? |
|
We
found a Klebsiella pneumoniae resistant to Tobramycin and sensitive to
Gentamicin and Amikacin. Repeating tests did not change anything. Is this
okay to report as Gentamicin Sensitive? |
|
Regarding
susceptibility testing: We are currently using the Microscan system to
perform identification and susceptibilities. A speaker from a recent
conference recommended inoculating the purity plates from the growth
control wells, rather than from the inoculum water tube (or current
process). The speaker stated that this would help verify that our Renok
inoculator was working properly. Could this then replace our current QA of
weighing the Renok before and after aspiration of the fluid? Is there a
policy or reference that addresses this question? |
|
What
are the mic's (breaking points) for in vitro susceptibility testing for
Streptococcus agalactiae for cefazoline? |
|
I
am updating my procedures for screening for MRSA and VRE. Is it adequate
to use only a Mannitol salt agar for primary setup for MRSA or should
there be additional media? For VRE screen is Bile Esculin Azide agar with
6mcg/ml Vancomycin adequate? These are Remel products. |
|
Out
infectious disease physician wants susceptiblity for stenotrophomonas
maltophilia against septra. Are there any guidelines and would a disk
diffusion or breakpoint MIC be sufficient? |
|
I
would like to know if anyone is experiencing problems with the vitek QC of
the 124 GNS card. Our Ps. aeruginosa ATCC 27853 is not coming in range for
gent. |
|
This
question is in regards to Staph aureus with inducible clindamycin
resistance. We have just recently started performing the induction test on
erythromycin resistant/clindamycin sensitive Staph aureus, when requested
by the physician. We have tested only 4 isolates so far, but they have all
shown the inducible resistance. Have there been any studies done to
determine what percent of the Staph aureus isolates with this sensitivity
pattern will have the inducible clindamycin resistance? |
|
We
do pip/tazo QC on E. coli 35218. To QC piperacillin, should we be using E.
coli 35218 or E. coli 25922. We often have problems in our QC with 35218
with small colonies within the zone. Both of these QC organisms have
defined QC zones in the NCCLS standards. |
|
Should
we be concerned with inducible clindamycin resistance for all
Erythromycin-resistant and Clindamycin-sensitive staphylococcal isolates,
or just S. aureus? Does this apply to streptococci also? I attended a
meeting recently where the speaker mentioned checking for inducible
clindamycin resistance in reference to sensitivity testing of Group B
Streptococcal isolates from pre-natal patients that are penicillin
allergic. |
|
We
have been getting inquiries about doing sensitivity testing on Grp A beta
hemolytic strep to Penicillin. The folks who are asking say there has been
reported resistance in recent literature. I know that the resistance to
some other antimicrobials may be increasing but I don't know of any
references pertaining to increased Penicillin resistance in these bugs. Do
you have any references pertaining to this? |
|
Cefepime
sales rep came in today to say that VITEK and MICROSCAN are reporting
intermediate and resistant results for Ps aeruginosa with cefepime. Says
we should drop cefepime disk to confirm. She also said it was reported to
FDA but it is hung up in court??? Any insight into this? |
|
I
understand that the guildelines from the Infectious Diseases Society of
America recommend using a fluoroquinolone or nitrofurantoin as first line
treatment for uncomplicated urinary tract infections if the resistance
rate of e. coli to tmp-sulfa is over 10% to 20% in our practice area. How
do we find out what the resistance rate is in the area of Madison,
Wisconsin? |
|
If
an Enterobactericeae is resistant to cefoxitin, the Microscan ALERT
software notifies the user to first rule out an ESBL and if not an ESBL to
consider the possibility of beta lactam resistance caused by an AMP C
enzyme. I cannot find out what the next step should be. I do have one
article by D.M. Livermore et al. sent to me by Microscan that says 2nd and
3rd generation cephalosporins should not be used. Elsewhere in the
Livermore article, it says that resistance is only conferred to
ceftazidime and cefotaxime. On the other hand, an article in the Journal
of Clinical Microbiology said that AMP C production is not a problem in
E.coli. So, can you tell me, reporting-wise, what we should I be doing
with an enterobacteriaceae that could have AMP C enzyme? |
|
Should
the D test be used for clinically significant coagulase negative
staphylococcus? |
|
What
is the consensus on treating bacteremia due to E. fecalis that is not
associated with endocarditis? For example, a line infection, UTI with
bacteremia? Would most people treat with both Ampicillin (if susceptible)
plus gentamicin if no evidence of endocarditis or prosthesis infection? |
|
We
perform weekly Q.C. on our Vitek GNS susceptibility cards using four ATCC
organisms, on one occasion we had one antibiotic from one ATCC organism
that had a deviation, we found no obvious reason for the deviation. We
repeated the ATCC organism from the sterility plate and the repeat had not
deviation. This was the only occasion during our weekly testing with that
lot number. Should we have done the 3 days of testing? Should we have
repeated our patients? If so, only those patients from the day of Q.C.
testing or all patients with that lot of GNS susceptibility testing from
the last Q.C. testing with no deviation? |
|
The
ASCP workshop recently gave information that enterococcus in urine
cultures (even VRE) should not have susceptibility testing performed. It
was indicated that any antibiotic will treat the organism in urine
cultures. I believe specific antibiotics were mentioned that could be used
as part of a disclaimer statement. Do you know of any sources that can be
provided to physicians and pathologists on this situation? |
|
Is
there any problem in treating non-ESBL producing Klebsiella with a third
generation cephalosporin such as Ceftriaxone as a single agent? |
|
What
QC strain should be used when perfroming the "D test" for
inducible clindamycin resistance in Staph aureus? |
|
can
e.faecalis be resistant to penicillin and sensitive to ampicillin |
|
Is
there a rapid method for identification of Staph saprophyticus? If
susceptibilities are run on significant coag neg staph isolates from
urine, would you recommend not running oxacillin (greater than 80% of CNS
are resistant)? |
|
The
current NCCLS document for MIC testing states that routine testing of
Staphylococcus saprophyticus urinary isolates is not advised because these
organisms respond readily to conventional therapy. Since we use an
automated system and the antimicrobial susceptiblity results are available
whether or not we report them out, are we in violation of NCCLS document
if we choose to report out information that we have? |
|
MRSA
therapy - Is it standard practice to add gentamicin and/or rifampin to
Vancomycin? I needed references! |
|
I
need a reference that states that repeated disk diffusion zone diameter
readings within 2 mm are acceptable and not considered errors. We have
always used this "rule of thumb" (for compentency testing), but
now I cannot find a reference. Also, I would like definitions of major and
minor errors for disk diffusion and MIC. Thank you |
|
How
do we interpret amoxicillin/clavulanic acid,
ampicillin-sublactam,cefuroxime and ceftriaxone on beta lactamase
positive, ampicillin resistant Hemophilus influenzae isolates? We use
Kirby Bauer method. |
|
Hello,
I have identified with API 20E an Enterobacter cloacae that shows
susceptibility to Ampicilin, Amoxi-clav, Cephalothin, cefoxitin, and
cefuroxime. Is this normal? |
|
What
is the standard for performing an MIC susceptibility test on Pastuerella
multocida? |
|
We
recently had a pseudomaonas sp. that was resistant to ciprofloxacin and
sensitive to levofloxacin. Are these results accurate for in vivo use
since these are in the same drug class and are showing contradiction? |
|
What
is a common sense, cost efficient protocol for screening for MRSA? We
offer a MRSA screen culture, where we use to check for any Staph, do a
staph latex, and if latex positive then we would set up an Oxacillin agar
plate. However, we have had one incident where we discovered by accident
that a staph latex positive, oxacillin agar resistant organism was not a
Staph aureus. Now I feel like we need to do full biochemical ID's on all
staph latex positives isolates. A Staph isolated from a routine culture
gets a full biochemical ID and sensitivity panel--so it is only the
specific screen that I am concerned about. Also, are there any guidelines
on how the MRSA latex test can be used? Is it only a screen to give a
preliminary result until the oxacillin agar is done, or can it replace the
oxacillin agar? |
|
Can
Haemophilus influenzae be sensitive to Ampicillin and resistant to
Cefaclor? We sometimes get this result and is it alright to report it as
such? Thanks for your help. |
|
Can
a bacterial isolate be resistant to meropenem and sensitive to imipenem?
How can we interpret such results? |
|
My
interpretation of NCCLS guidelines for the susceptibility testing of
Neisseria meningitidis and Alcaligenes xylosoxidans is that there are no
interpretive guidelines for these two organisms. Is that correct? |
|
Is
it necessary to do sensitivity testing on all isolates of Moraxella
catarrhalis from lower respiratory tract specimens? |
|
Our
hospital is using Mupirocin in surgeons and patients. Is there an approved
method of testing for resistance? |
|
When
we observe resistance to 1st gen cephalosporins but sensitive to
ampicillin in clinical isolates of enterobacteriaceae, is it necessary to
modify the result or report just as it is. c.r.setty settycr@yahoo.com |
|
Is
is necessary to perform susceptibility testing on group B strep isolates
from vaginal/rectal swabs? |
|
Hello!
Can someone please suggest guidelines for determining which antimicrobials
should ordinarily be tested and reported (if any) from Aeromonas and
Vibrio species from stool cultures? These genera aren't listed on Table 1
of NCCLS M100-S12. Some of our staff have been following the guidelines
for Enterobacteriaceae, some have been following those for "other
nonfastidious nonfermenters," and these 2 genera don't fit either
category. I am embarassed to admit I never realized we had this problem
until now. Thanks! |
|
How
should we read and interprete amoxicillin/clavulanat and pip/tazobactam
(disk difusion) on isolates of E. coli that produce ESBL? |
|
There
are some reports on detecting ESBL using double disk synergy test on
gram-negative organisms other than E.coli and Klebsiella. I know that this
method is not standardized by NCCLS for these bacteria and other enzymes
such as ampC may interfere with ESBL during double disk synergy testing.
Am I wrong? |
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