Abstract
In Japan, sustainable national antimicrobial resistance (AMR) monitoring has been established in both human and veterinary fields. However, AMR monitoring in the environment, including wildlife, remains limited. This study aimed to assess the possibility of sustainable monitoring using wild deer transported to slaughterhouses and wild foxes surveyed for Echinococcus multilocularis. Escherichia coli, a common AMR indicator bacterium, was isolated from rectal swabs of deer and foxes using Chromagar ECC, with and without antimicrobials (cefotaxime (CTX) or nalidixic acid (NA). Antimicrobial susceptibility was determined, and β-lactamase genes were detected using polymerase chain reaction. Plasmids carrying β-lactamase genes were analyzed by whole-genome sequencing. A total of 104 E. coli strains were isolated from (103/120, 85.8%) deer and 61 strains from (56/99, 56.6%) foxes using medium without antimicrobials. Using a medium containing CTX and NA, two and three strains were isolated, respectively, exclusively from foxes. All deer strains were susceptible to the tested antimicrobials. However, 0-11.5% of fox strains from medium without antimicrobials (n=61) demonstrated resistance. Three strains from foxes had β-lactamase genes in plasmid. Finally, this study demonstrates the feasibility of sustainable AMR monitoring using wild deer transported to a slaughterhouse and wild foxes surveyed for E. multilocularis.