Elevated risk of carrying gentamicin-resistant Escherichia coli among U.S. poultry workers

Background: Antimicrobial use in food-animal production is an issue of growing concern. The application of antimicrobials for therapy, prophylaxis, and growth promotion in broiler chicken production has been associated with the emergence and dissemination of antimicrobial-resistant enteric bacteria. Although human exposure to antimicrobial-resistant bacteria through food has been examined extensively, little attention has been paid to occupational and environmental pathways of exposure.

Objective: Our objective was to measure the relative risk for colonization with antimicrobial-resistant Escherichia coli among poultry workers compared with community referents.

Methods: We collected stool samples and health surveys from 16 poultry workers and 33 community referents in the Delmarva region of Maryland and Virginia. E. coli was cultured from stool samples, and susceptibility to ampicillin, ciprofloxacin, ceftriaxone, gentamicin, nitrofurantoin, and tetracycline was determined for each E. coli isolate. We estimated the relative risk for carrying antimicrobial-resistant E. coli among poultry workers compared with community referents.

Results: Poultry workers had 32 times the odds of carrying gentamicin-resistant E. coli compared with community referents. The poultry workers were also at significantly increased risk of carrying multidrug-resistant E. coli.

Conclusions: Occupational exposure to antimicrobial-resistant E. coli from live-animal contact in the broiler chicken industry may be an important route of entry for antimicrobial-resistant E. coli into the community.