A new study said antimicrobial resistance rates may display seasonal variation, peaking in winter, that could result from the seasonality of infectious diseases and accompanied antibiotic use.
Bacterial respiratory infections are a leading cause of morbidity and mortality; concurrently, respiratory bacteria have increasingly become resistant to several antibiotics, with the prevalence of resistant strains growing rapidly. A new study said antimicrobial resistance (AMR) rates may display seasonal variation, peaking in winter, that could result from the seasonality of infectious diseases and accompanied antibiotic use.
Streptococcus pneumoniae and Haemophilus influenzae are a common cause of community-acquired pneumonia and meningitis in children worldwide. In 2017, the World Health Organization included S. pneumoniae and H. influenzae on the list of priority bacteria for which new antibiotics are needed; about 20% to 30% of all pneumonias are caused by multidrug-resistant S. pneumoniae and about 30% to 40% are caused by penicillin-resistant S. pneumoniae. Resistant infections lead to a longer stay in hospital, higher health-care costs, and increased mortality.
Emerging evidence suggests that AMR rates in respiratory bacteria show seasonal variation but results are highly variable among studies. Writing in PLos One, researchers assessed the seasonality of AMR rates in respiratory bacteria by searching 7 electronic databases (Embase.com, Medline Ovid, Cochrane CENTRAL, Web of Science, Core Collection, Biosis Ovid, and Google Scholar). They included studies describing resistance rates of S. pneumoniae and H. influenzae, using random-effects meta-analysis. Pooled odd ratios (OR) of seasonal AMR rates were calculated using winter as the reference group, and pooled odd ratios were obtained by antibiotic class and geographical region.
Of 13 included studies, 7 were meta-analyzed. Since few studies were done in H. influenzae, they were not quantitively analyzed.
AMR rates of S. pneumoniae to penicillins were lower in other seasons than in winter with pooled OR = 0.71; 95% CI = 0.65-0.77; I2 = 0.0%, and to all antibiotics with pooled OR = 0.68; 95% CI = 0.60-0.76; I2 = 14.4%. The seasonality of AMR rates in S. pneumoniae remained the same, independent of geographical region.
While more research is needed to understand the factors underlying the seasonality of AMR rates, such as the seasonal variation of antibiotic use and its association with antimicrobial resistance, the researchers said several actions could optimize antibiotic use in winter months:
Martinez EP, Cepeda M, Jovanoska M, et al. Seasonality of antimicrobial resistance rates in respiratory bacteria: A systematic review and meta-analysis [published online August 15, 2019]. PLoS One. doi: 10.1371/journal.pone.0221133.