LAUSR

Significance Antimicrobial resistance is a pressing concern, and while antibiotic stewardship interventions are intended to limit unnecessary antibiotic exposures, including to asymptomatically carried pathogens (i.e., bystander exposure), the frequency and characteristics of these bystander exposures have not been well described. We quantified the frequency that bacterial enteric pathogens were exposed to antibiotics when not the target of treatment in a study of children in low-resource settings. Our analysis demonstrated that almost all enteropathogen exposures to antibiotics occurred when the bacteria were carried asymptomatically, and respiratory infections were responsible for the largest proportion of exposures. Interventions to reduce antibiotic use and the illnesses that prompt treatment could have the ancillary benefit of reducing selection pressure for antimicrobial resistance among pathogens carried asymptomatically.