Campylobacter in wintering great tits Parus major in Poland

Domestic and wild mammals, domestic birds and particularly wild birds are considered to be reservoirs of many species of Enterobacteriaceae, and also important human enteric pathogens, e.g., the bacteria of the genus Campylobacter that occur in their digestive tracts. These species may be vectors of antimicrobial resistance dissemination in the environment, because they may have contact with an environment contaminated with antibiotics. Bird feeders have been suggested as potential dispersal centres between wild wintering birds whose feeding is supported by humans. Therefore, we checked for the presence of Campylobacter bacteria among great tits Parus major, the most common bird species on bird feeders in Poland. Samples (n = 787 cloacal swabs) were collected in urban and rural areas of Poland. Bacterial species were identified using multiplex PCR, and 23 (2.9%) positive tests for Campylobacter spp. were found; in ten samples, C. jejuni was detected. The odds ratio of Campylobacter infection in rural birds was over 2.5 times higher than urban birds. Ten samples with C. jejuni were tested for antibiotic resistance, and all were sensitive to azithromycin, erythromycin and gentamycin, while six isolates were resistant to tetracycline, and five were resistant to ciprofloxacin. Four Campylobacter isolates were resistant to both these antibiotics.