Enterobacteriaceae Harboring AmpC (blaCMY) and ESBL (blaCTX-M) in Migratory and Nonmigratory Wild Songbird Populations on Ohio Dairies.
Extended-spectrum β-lactamases (ESBLs) confer bacterial resistance to critically important antimicrobials, including extended-spectrum cephalosporins (ESCs). Livestock are important reservoirs for the zoonotic food-borne transmission of ESC-resistant enteric bacteria. Our aim is to describe the potential role of migratory and resident wild birds in the epidemiology of ESBL-mediated bacterial resistance on dairy farms. Using mist nets, we sampled wild migratory and resident birds either immediately adjacent to or 600 ft away from free-stall barns on three Ohio dairy farms during the 2014 and 2015 spring migrations. Individual swabs were used to obtain both a cloacal and external surface swab from each bird. Samples were inoculated into MacConkey broth containing cefotaxime then inoculated onto MacConkey agar with cefoxitin, cefepime, or meropenem to identify the blaCMY,blaCTX-M,and carbapenemase phenotypes, respectively. Six hundred twenty-three birds were sampled, 19 (3.0%) of which harbored bacteria with blaCMYand 32 (5.1%) harbored bacteria with blaCTX-Mfrom either their cloacal sample or from their external swab. There was no difference in the prevalence of either gene between migratory and resident birds. Prevalence of blaCMYand blaCTX-Mwas higher among birds sampled immediately outside the barns compared with those sampled 600 ft away. Our results suggest that wild birds can serve as mechanical and/or biological vectors for Enterobacteriaceae with resistance to ESCs. Birds live in close contact with dairy cows and their feed, therefore, transmission locally between farms is possible. Finding a similar prevalence in migratory and nonmigratory birds suggests the potential for regional and intercontinental movement of these resistance genes via birds.
1 Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio.
Dimitria A
DA
Mathys
2 Division of Mathematics, Computer and Natural Sciences, Ohio Dominican University , Columbus, Ohio.
Blake A
BA
Mathys
1 Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio.
Dixie F
DF
Mollenkopf
3 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio.
Joshua B
JB
Daniels
1 Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University , Columbus, Ohio.
Thomas E
TE
Wittum
D025041:Animal Migration; D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology / Q000382:microbiology*; D003612:Dairying; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000235:genetics*; D009820:Ohio / Q000453:epidemiology; D020308:Songbirds / Q000382:microbiology*; D015047:Zoonoses
antimicrobial resistance; epidemiology; public health; wild birds