Common non-antibiotic drugs enhance selection for antimicrobial resistance in mixture with ciprofloxacin

This study shows that antimicrobial resistance (AMR) can be promoted not only by antibiotics but also by mixtures of antibiotics and non-antibiotic drugs (NADs). Researchers tested three NADs in combination with the antibiotic ciprofloxacin and found that these mixtures changed how resistance developed and altered microbial community composition. Compared to ciprofloxacin alone, the combinations more strongly selected for certain AMR genes (e.g., qnrB and intI1). The findings highlight that real-world drug mixtures can enhance AMR selection, and future research should account for interactions between antibiotics and NADs when assessing drivers of resistance.