Widespread antimicrobial use in laboratory rodent vivaria in North America revealed by a cross-sectional survey of American College of Laboratory Animal Medicine certified veterinarians

Antimicrobial resistance (AMR) is a major global threat to human health, animal welfare and sustainable development. Whilst resistance can arise naturally, inappropriate antimicrobial exposure accelerates its emergence. Recognizing this risk, international One Health initiatives emphasize reducing antimicrobial use, especially of drugs considered critical for human medicine. Much of the evidence guiding these efforts comes from food-producing and companion animals, but antimicrobial use in laboratory animals, particularly rodents, remains poorly described. To address this gap, we surveyed all veterinarians certified by the American College of Laboratory Animal Medicine in the United States (921) and Canada (10). A total of 157 veterinarians completed the survey, resulting in a 16.9% overall response rate. The response rate was 16.6% for participants in the United States and 40.0% for those in Canada. Despite a strong response, the small number of eligible veterinarians restricts data extrapolation in the Canadian context. Survey results showed that antimicrobial use is common and routine in rodent vivaria. Overall, 91.7% of respondents reported regular antimicrobial use. Applications included both clinical treatment and research purposes such as induction of microbiome dysbiosis, prophylaxis in immunocompromised rodents and gene induction. Reported drug classes included fluoroquinolones and third-generation cephalosporins, with some use of glycopeptides and carbapenems, all considered critically important to human health. Disposal practices often involved release into sewerage or landfill without inactivation, raising environmental concerns. These findings suggest that antimicrobial use in laboratory rodents may represent an underrecognized contributor to AMR and highlight the importance of targeted stewardship.