New research indicates that wildlife, specifically birds and foxes, can act as crucial early warning systems for antibiotic resistance (AMR) spreading through ecosystems.
The study, published in Frontiers in Microbiology, analyzed fecal samples from nearly 500 birds and red foxes. These samples were tested for enzyme-encoding genes that confer resistance to essential antibiotics like third-generation cephalosporins (3GCs), commonly used for severe infections.
These resistance genes can be carried by bacterial groups like ESKAPE pathogens. Notably, Klebsiella pneumoniae, an ESKAPE bacterium, can cause severe human infections and has been found in wildlife far from direct human antibiotic exposure. Researchers isolated a high-risk ST307 clone of K. pneumoniae and the NDM-5 carbapenemase enzyme from such wildlife.
The findings suggest birds are primary dispersers of resistance over long distances via air, while foxes contribute to shorter-range dissemination on land. Klebsiella spp. was found in 32 samples, with K. pneumoniae present in 2% of samples, predominantly in foxes and waterbirds.
This wildlife resistance found in the study exceeded clinical rates, with 100% of K. pneumoniae isolates from wildlife showing resistance to 3GCs, compared to 19.6% in human patients in Italy. Researchers highlight that even a low prevalence in wildlife signifies environmental contamination by high-risk clones.
To combat AMR, enhanced wastewater treatment and more cautious use of antimicrobials in livestock are recommended. Experts advocate for routine wildlife AMR monitoring as a public health early warning system to guide environmental interventions before resistance impacts clinical settings.