Monday, 18 September 2017 16:48

Decreasing MRSA rates provide positive reinforcement for antibiotic stewardship efforts

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Published in mBiosphere

Healthcare workers and public health officials alike have been promoting antibiotic stewardship to preserve the use of antibiotics for their appropriate applications (such as in treating susceptible bacterial infections, rather than treating viral infections). These efforts have produced good results in the form of an August 2017 report of a decrease in the rate of antibiotic prescriptions. Following on that good news, a new Antimicrobial Agents and Chemotherapy study documents a decrease in methicillin-resistant Staphylococcus aureus diagnoses in U.S. hospitals.

AACJournal: Antimicrobial susceptibility trends among Staphylococcus aureus isolates from U.S. hospitals: Results from 7 years of the Ceftaroline (AWARE) surveillance program, 2010 to 2016.

MRSA rates 2S. aureus antimicrobial susceptibilities by year (2010-2016). Source.

Lead author Helio Sader and senior scientist Robert Flamm looked at the susceptibility of more than 21,000 S. aureus isolates from 42 medical centers across the country. Each isolate was tested by broth microdilution for its ability to grow in the presence of a variety of antibiotics. Overall, the trend of resistant infections was promising, with a decrease in methicillin-resistant isolates from 50% (682 of 1364) of isolates in 2010 to 42.2% (1493 of 3536) of isolates in 2016 (see right).

One slightly worrisome trend in the data is the decrease of methicillin-susceptible S. aureus strain susceptibility to other antibiotics, such as clindamycin or levofloxacin. Resistance to these or other drugs may increase if physicians prescribe these preferentially over methicillin and other cell wall-active drugs. However, no change in susceptibility trends was noted for daptomycin, linezolid, vancomycin, or tigecycline, and resistance to these drugs remains rare in S. aureus isolates.

The problem of antibiotic resistance can seem overwhelming, but reports like these help buoy the spirits of those working to preserve antibiotics. Stewardship efforts are having positive effects, both in the use of antibiotics and in their efficacy. Now it’s up to collaborations between scientists and their communities to continue these efforts, and the positive trends that accompany them.

Cover photo of S. aureus colonies

Last modified on Tuesday, 19 September 2017 13:22
Julie Wolf

Julie Wolf is the ASM Science Communications Specialist. She contributes to the ASM social media and blog network and hosts the Meet the Microbiologist podcast. She also runs workshops at ASM conferences to help scientists improve their own communication skills. Follow Julie on Twitter for more ASM and microbiology highlights at @JulieMarieWolf.

Julie earned her Ph.D. from the University of Minnesota, focusing on medical mycology and infectious disease. Outside of her work at ASM, she maintains a strong commitment to scientific education and teaches molecular biology at the community biolab, Genspace. She lives in beautiful New York City.