Analysis of antimicrobial resistance and PFGE patterns of Salmonella spp. isolated from chickens at slaughterhouse in Incheon area

Salmonella spp. are the important pathogens both economically and clinically in animals as well as human. Some of them have highly zoonotic potentials even though they are asymptomatic in animals. Therefore, the prevalence of Salmonella spp. in animals is highly concerned for human health. The present study was carried out to investigate the prevalence, antimicrobial resistance and PFGE patterns of Salmonella spp. isolated from chickens at slaughterhouse in Incheon area. The overall isolation rate of Salmonella spp. from cloaca and cecum specimens was 7.3 % (37/510). Thirty seven isolates of Salmonella spp. were identified to 5 serotypes; S. Enteritidis, S. Newport, S. Typhimurium, S. Gallinarum, and S. Derby with prevalence of 46.0%, 40.5%, 8.1%, 2.7%, and 2.7%, respectively. Resistance to nalidixic acid was found in 97.3% of Salmonella spp. isolated, followed by streptomycin (16.2%), tetracycline (16.2%), ampicillin (5.4%). Only 6 isolates (16.2%) showed resistance to more than two antimicrobials. In PFGE analysis of chicken and human isolates with Xba I, S. Enteritidis isolates from chicken showed very high similarity over 82.8% and also the similarity was very high in the comparison with human isolates. However, the higher similarity (100%) was observed among chicken isolates of S. Typhimurium. These results suggest the close genetic relatedness of Salmonella spp. isolated from chickens with human.