MODRALL, JENNIFER*; WHEELER, TERRI; POKRAS, MARK; ROMERO, L. MICHAEL: The impact of veterinary administration of antibiotics on the bacterial ecology of wild bird populations

This study investigated whether veterinary uses of antibiotics have altered the bacteria ecology within surrounding wild bird populations. Antibiotics have been commonly used in animal husbandry for over 30 years. There is convincing evidence that these agricultural practices have created antibiotic resistance in farm animals, and that resistance can be transferred to farm workers and consumers. Wild birds foraging at farm and veterinary sites may be exposed to antibiotics and/or antibiotic resistant bacteria. We surveyed wild House sparrows(Passer domesticus) at two sites with different antibiotic usage: Tufts University’s Veterinary and Main campuses. Cloacal bacterial samples were analyzed for the presence of enteric bacteria species, such as E.coli, Salmonella and Campylobacter. Sensitivities to 7 antibiotics commonly used at the veterinary hospital were assessed. The bacterial species composition and frequency differed between the two sites; for example E.Coli and Streptococcus species were more frequently found at the veterinary campus. No Salmonella was isolated. Campylobacter species were found approximately equally at both sites. The antibiotic sensitivity patterns of bacteria from House sparrows were notably different between the veterinary and suburban locations. The creation of large reservoirs of antibiotic resistance in wild birds and other animals could threaten human and livestock health and have unforeseen consequences for wild animals. Due to their great mobility, birds could be an important transmission vector of antibiotic resistance. This study provides evidence that certain wild bird populations may already be potential reservoirs of antibiotic resistant bacteria.