The Zika ThreatASM Acts to Counter Zika Virus Outbreak.
Jennifer R. Verani, M.D.
Office of Infectious Diseases
Centers for Disease Control and Prevention
1600 Clifton Road
Atlanta, GA 30333
Dear Dr. Verani:
Thank you for the opportunity to review the Center for Disease Control and Prevention’s (CDC) draft revised guidelines for the Prevention of Perinatal Group B Strep (GBS) Infection. The American Society for Microbiology’s Committees on Laboratory Practices and Professional Affairs reviewed the laboratory portion of the draft and submit the following comments for your consideration:
a) No source/reference is given for this recommendation.
b) Is there literature to support that mixed urine cultures from pregnant women with > 104 cfu/ml of GBS as well as 2 or more other uropathogens or contaminants are a significant factor which will lead to newborn disease?
c) The recommendation to report GBS in mixed urine cultures represents increased workload for clinical microbiology laboratories that generally do not distinguish and report bacterial growth in urine specimens that grow > 3 organisms (i.e., contaminated specimens). Special work up for GBS in urine specimens that are contaminated with mixed fecal flora from all women of reproductive age is contraindicated and may lead to inappropriate antibiotic therapy and increased cost, and potentially expose the patient to an unwarranted risk of drug toxicity while exerting pressure for the development of avoidable antibiotic resistance.
d) As previously stated in the draft revised guidelines, it is true that laboratories rarely know whether urine samples are from pregnant women; as a result, the vast majority of laboratories would need to identify all possible streptococci (beta-haemolytic and non-haemolytic) for the possibility of GBS in all mixed urine cultures from all women of reproductive age (and reproductive age has not been defined).
We submit that the references cited in support of routine screening for asymptomic bacteriuria in pregnant women utilize significant quantities of uropathogens AND clinical significance to the number of organisms growing, i.e., liberally, 2 potential pathogens in a urine culture each at a quantity of > 104cfu/ml. If data exists to show similar clinical importance of mixed urine cultures, it should be stated in the new guidelines. If such data does not exist, the guidelines should limit routine screening to clinically significant culture results as defined by each laboratory or as defined in the 2009 Cumitech on Laboratory Diagnosis of Urinary Tract Infections (already referenced in your guideline).
Thank you again, for the opportunity to comment. Please let us know if ASM can provide any further clarification.
Susan E. Sharp, Ph.D., Chair, Committee on Laboratory Practices
Public and Scientific Affairs Board