Prevalence and antimicrobial susceptibility of Campylobacter coli isolates from swine

Abstract

Swine is a common source of Campylobacter coli human gastroenteritis, for the treatment of which erythromycin and fluoroquinolones are recommended. The prevalence of antimicrobial-resistant C. coli differs significantly depending on countries. We investigated the prevalence of C. coli in swine from a farm in Buan-gun, Korea in 2010, and determined antimicrobial susceptibility of the isolates. Rectal swab specimens were used to inoculate Campylobacter Preston media and incubated microaerophilically at 42°C for 48 h. The species were identified by phenotypic tests and by detecting hipO and glyA genes. PCR was used to detect mutations of A2074C in 23S rRNA gene, and quinolone resistancedetermining region (QRDR) of gyrA, which are associated with high level resistance to erythromycin, and with ciprofloxacin, respectively. Antimicrobial susceptibility was determined by the disk diffusion and agar dilution tests. Of the 100 specimens, 55 (55%) yielded C. coli, and 23 of them (41.8%) had A2074G mutation. A2074G mutated isolates showed the lowest MIC90 of imipenem, while those of ampicillin and clindamycin were relatively low. The majority of both A2074G mutation-positive and -negative isolate were susceptible to ampicillin, cefotaxime, and chloramphenicol. All isolates were resistant to ciprofloxacin, and had mutation in QRDR of gyrA. In conclusion, C. coli was detected in 55% of swine, and A2074G mutation was detected in 41.8% of the isolates. All isolates had gyrA mutation-mediated ciprofloxacin resistance.