Antimicrobial susceptibility of Riemerella anatipestifer strains isolated from geese and ducks in Hungary.

Riemerella anatipestifer causes anatipestifer disease in many avian species. A total of 185 R. anatipestifer strains isolated in Hungary between 2000 and 2014 from geese and ducks were tested against 13 antibiotics (ampicillin, doxycycline, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, penicillin, spectinomycin, streptomycin, sulphamethoxazole-trimethoprim, sulphonamide compounds, and tetracycline) by the Kirby-Bauer disk diffusion method. The majority of the strains were susceptible to florfenicol (97.9%), ampicillin (95.1%), penicillin (93%), sulphamethoxazole-trimethoprim (92.4%), and spectinomycin (86.5%). The highest resistance rates were observed for flumequine, tetracycline, erythromycin and streptomycin (94%, 91.4%, 75.1% and 71.4% resistance, respectively). The resistance patterns showed some variation depending on the geographical origin of the strains. The average rate of extensive drug resistance was 30.3%, and its proportion tended to increase in the period examined.