Quantifying antibiotic impact on within-patient dynamics of extended-spectrum beta-lactamase resistance.

Antibiotic-induced perturbation of the human gut flora is expected to play an important role in mediating the relationship between antibiotic use and the population prevalence of antibiotic resistance in bacteria, but little is known about how antibiotics affect within-host resistance dynamics. Here we develop a data-driven model of the within-host dynamics of extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae . We use bla _CTX-M (the most widespread ESBL gene family) and 16S rRNA (a proxy for bacterial load) abundance data from 833 rectal swabs from 133 ESBL-positive patients followed up in a prospective cohort study in three European hospitals. We find that cefuroxime and ceftriaxone are associated with increased bla _CTX-M abundance during treatment (21% and 10% daily increase, respectively), while treatment with meropenem, piperacillin-tazobactam, and oral ciprofloxacin is associated with decreased bla _CTX-M (8% daily decrease for all). The model predicts that typical antibiotic exposures can have substantial long-term effects on bla _CTX-M carriage duration.
Competing Interests: RN, Ev, YM, AT, CL, YC, HG, ET, BC, LP, SM No competing interests declared, BC Reviewing Editor, eLife
(© 2020, Niehus et al.)