Abstract

The objective of this study was to ascertain the nationwide prevalence and antimicrobial resistance rates of Salmonella spp. and Escherichia coli amongst domesticated finisher pigs. Fecal samples (n=840) were collected at 84 slaughterhouses in Korea in May 2009.Salmonella spp. was isolated from 21 of the 840 samples (2.5%), and comprised the following isolated serotypes: Salmonella rissen, Salmonella derby, Salmonellatyphimurium. Antimicrobial susceptibility testing was performed for eight antimicrobials.Salmonella resistance was tetracycline (76.19%); nitrofurantoin (38.10%); kanamycin (33.33%); chloramphenicol, sulfamethoxazole/trimethoprim and cephalothin (28.57%); polymyxin B (9.52%); and ampicillin/sulbactam (4.76%), and E. coli resistance was tetracycline (87.11%); chloramphenicol (66.24%); kanamycin (51.68%); sulfamethoxazole/trimethoprim (51.29%); cephalothin (8.38%); nitrofurantoin (5.15%); ampicillin/sulbactam (4.64%); and polymyxin B (0.52%). Tetracycline resistance was most common. Surprisingly, 28.57 and 66.24% of the Salmonella spp. and E. coli isolates, respectively, were resistant to chloramphenicol, which has been banned from agricultural use in Korea for some time. A wide range of strains displayed multi-antimicrobial resistance: 14 out of 21 (66.66%) and 611 out of 776 (78.72%) of the Salmonella and E. coli isolates, respectively. Salmonella spp. and E. coli demonstrate an appreciable broad-spectrum, (multi)-antimicrobial resistance, which is a potential public health concern. A continuous antibiotic surveillance program may be worthwhile.

Key words: Swine, pig, Salmonella spp., Escherichia coli, antimicrobial resistance, slaughterhouse