*Article* **Antibiotic Susceptibility, Genetic Diversity, and the Presence of Toxin Producing Genes in** *Campylobacter* **Isolates from Poultry**

**Jeeyeon Lee 1,2, Jiyeon Jeong 1, Heeyoung Lee 2, Jimyeong Ha 1,2 ID , Sejeong Kim 1,2, Yukyung Choi 1,2, Hyemin Oh 1,2, Kunho Seo 3, Yohan Yoon 1,2,\* and Soomin Lee 2,\***


Received: 27 September 2017; Accepted: 14 November 2017; Published: 17 November 2017

**Abstract:** This study examined antibiotic susceptibility, genetic diversity, and characteristics of virulence genes in *Campylobacter* isolates from poultry. Chicken (*n* = 152) and duck (*n* = 154) samples were collected from 18 wet markets in Korea. *Campylobacter* spp. isolated from the carcasses were identified by PCR. The isolated colonies were analyzed for antibiotic susceptibility to chloramphenicol, amikacin, erythromycin, tetracycline, ciprofloxacin, nalidixic acid, and enrofloxacin. The isolates were also used to analyze genetic diversity using the DiversiLabTM system and were tested for the presence of cytolethal distending toxin (*cdt*) genes. *Campylobacter* spp. were isolated from 45 poultry samples out of 306 poultry samples (14.7%) and the average levels of *Campylobacter* contamination were 22.0 CFU/g and 366.1 CFU/g in chicken and duck samples, respectively. Moreover, more than 90% of the isolates showed resistance to nalidixic acid and ciprofloxacin. Genetic correlation analysis showed greater than 95% similarity between 84.4% of the isolates, and three *cdt* genes (*cdtA*, *cdtB*, and *cdtC*) were present in 71.1% of *Campylobacter* isolates. These results indicate that *Campylobacter* contamination should be decreased to prevent and treat *Campylobacter* foodborne illness.

**Keywords:** *Campylobacter*; poultry; antibiotic susceptibility; Rep-PCR; *cdt* toxin
