Prevalence of Antimicrobial-Resistant Escherichia coli in Migratory Greater White-Fronted Geese (Anser albifrons) and their Habitat in Miyajimanuma, Japan.

The spread of antimicrobial-resistant bacteria (ARB) in natural environments including wild animals is a concern for public health. Birds cover large areas, and some fly across borders to migrate in large flocks. As a migratory bird, the Greater White-fronted Goose (Anser albifrons) travels to Miyajimanuma, North Japan, each spring and autumn. To investigate the ARB in migratory birds and their surroundings, we collected 110 fecal samples of A. albifrons and 18 water samples from Miyajimanuma in spring and autumn of 2019. Isolation of Escherichia coli was performed using selective agars with or without antimicrobials (cefazolin and nalidixic acid). Isolates of E. coli were recovered from 56 fecal samples (50.9%) and five water samples (27.8%) on agars without antimicrobials. No isolates were recovered on agars with antimicrobials. One E. coli isolate derived from a fecal sample exhibited resistance to β-lactams (ampicillin and cefazolin), whereas all other isolates exhibited susceptibility to all tested antimicrobials. The resistant isolate harbored blaACC, which could be transferred to other bacteria and confer resistance to β-lactams. These results suggest a low prevalence of antimicrobial resistance in wild migratory birds and their living environments; however, wild migratory birds sometimes carry ARB harboring transferrable antimicrobial resistance genes and therefore present a risk of spreading antimicrobial resistance. © Wildlife Disease Association 2021.