A recent study suggests red foxes and several common bird species may serve as an early warning system for highly antibiotic-resistant bacteria in wildlife. Their movements could provide valuable insights for public health officials, veterinarians, and dog and cat parents.
Researchers from the University of Parma in Italy discovered that wildlife now carry clinically important antibiotic resistance genes, even in areas where the animals have not been directly exposed to antibiotics. The findings highlight how antimicrobial resistance (AMR) is becoming a widespread environmental issue.
Wildlife on the move
The study focused on red foxes, crows, magpies, and waterbirds. These animals regularly move between urban, rural, and natural environments As they do so, they pick up and carry resistant bacteria from one environment to another.
Foxes may help spread resistant bacteria locally as they move through their territories. However, migratory birds can carry those bacteria across much greater distances, potentially introducing them to new regions.
To better understand the risks, researchers analyzed nearly 500 fecal samples and screened them for Klebsiella species, including K. pneumoniae. This bacterium belongs to the notorious “ESKAPE” group of pathogens. They’re known for their ability to evade many commonly used antibiotics and cause serious infections in both people and animals.
Concerning levels of resistance
The results were eye-opening. Researchers identified both the NDM-5 carbapenemase enzyme and the ST307 clone of K. pneumoniae in wildlife samples. Carbapenemases are particularly concerning because they can neutralize some of the most powerful antibiotics available, leaving few treatment options when infections occur.
The researchers found extremely high resistance rates in wildlife samples. About 19.6% of K. pneumoniae isolates from human patients in Italy are resistant to third-generation cephalosporins. However, all the wildlife isolates in the study showed resistance to that same class of antibiotics.
Wildlife isolates showed a similar pattern with fluoroquinolones, another important group of antibiotics. Again, 100% of the wildlife isolates were resistant, compared with 17.4% of human clinical isolates.
What does this mean for you and your dog or cat?
The overall prevalence of K. pneumoniae in the samples was relatively low at 2%. But the findings suggest wastewater, sewage, and runoff may be driving the circulation of resistant bacteria between people, animals.
According to lead study author Dr. Mauro Conter, routine monitoring of wildlife could help identify emerging resistance threats before they become widespread in human or veterinary medicine. The researchers recommend several steps to help slow the spread of antimicrobial resistance, including:
- Improving wastewater treatment and reducing antibiotic pollution
- Using antibiotics more responsibly in livestock production
- Reserving critically important antibiotics for human medicine whenever possible.
As human activity increasingly overlaps with natural ecosystems, scientists can use wildlife monitoring to track antibiotic resistance. This can help doctors and veterinarians stay ahead of emerging threats.
