Using Ongoing Wildlife Surveillance Programs to Monitor Antibiotic Resistant Bacteria in the Environment

The need to include wildlife in surveillance programs for antibiotic resistance has been previously highlighted. In the present study, we explored the possibility of sampling Swedish wildlife in conjunction with ongoing monitoring programs for wildlife health and disease to evaluate the occurrence of antibiotic resistance. The animals included in the study represented different trophic levels and degrees of interaction with humans, namely bears, eagles, wolves, foxes, otters, and hares. Samples were screened for ESBL-, pAmpC-, and carbapenemase-producing Escherichia coli using selective media, and indicator E. coli was also isolated from each sample. All isolates were tested for antimicrobial susceptibility, and a subset of isolates was genome sequenced. Two samples from foxes were found to carry ESBL- or pAmpC-producing isolates, while no carbapenemase-producing E. coli could be detected. Geographical information on the samples and genetic characterization of the ESBL- and pAmpC-producing isolates suggest that proximity to anthropogenic settings could play a role in the occurrence of antibiotic resistance in wildlife. In addition, the study demonstrated that the use of ongoing wildlife surveillance programs presents a cost-efficient possibility to monitor antibiotic resistance in wild animals. However, future studies and monitoring programs should take careful consideration regarding selection of animal species and distribution.