¹Department of Microbiology, Faculty of Veterinary Medicine, Mustafa Kemal University, TR-31040 Hatay - TURKEY DOI : 10.9775/kvfd.2016.17261 The objective of this study was to investigate the prevalence, antimicrobial resistance and genetic determinants of resistance of Campylobacter jejuni and Campylobacter coli isolated from commercial broiler farms in Adana and Hatay provinces, Turkey. The assessment of the genetic diversity among the isolates was determined by flaA based RFLP-Polymerase Chain Reaction (PCR) with restriction enzyme DdeI and sequence analysis of short variable regions (SVRs) of flaA and flaB-SVR genes. Antimicrobial susceptibility of the isolates was performed by disk diffusion method and tetracycline (tetO), ampicillin (blaOXA-61), aminoglycoside (aph-3-1) and multidrug efflux pump (cmeB) resistance genes were investigated by PCR as well. The genes conferring resistance to ciprofloxacin was screened by PCR and following DNA sequencing. The presence of ten virulence (flaA, virB11, racR, cadF, ciaB, dnaJ and pldA) and toxin genes (cdtA, dtB, cdtC) among the isolates was also investigated using PCR. Out of 220 cloacal swabs, 218 (99.1%) Campylobacter spp. including C. jejuni (n=194; 89%) and C. coli (n=24; 11%) were isolated. While all the isolates were susceptible to chloramphenicol, gentamicin and erythromycin, resistance rates for C. jejuni and C. coli isolates to nalidixic acid, ciprofloxacin, ampicillin, tetracycline and amoxicillin-clavulanic acid were determined as 86.6-100%, 86.6-100%, 45.9-45.8%, 43.3-50% and 2.6-0.0%, respectively. The tetO, blaOXA-61, cmeB and aph-3-1 genes detected in C. jejuni and C. coli isolates were 45.3-54.2%, 36.1-75%, 1.5-83.3% and 0.5-0%, respectively. The prevalence of flaA, cdtA, cdtB, cdtC, racR, cadF, ciaB, dnaJ and pldA in C. jejuni and C. coli isolates was 100-100%, 95.4-100%, 94.3-100%, 89.7-54.2%, 89.2-79.2%, 92.8-100%, 67-16.7%, 85.6-75% and 80-66.7%, respectively. virB11 gene was not detected in any of Campylobacter isolates. All flaA and flaB-SVR alleles displayed same PCR-RFLP patterns. The results of this study revealed high prevalence, pathogenic potantial, genetic diversity and antimicrobial resistance of Campylobacter spp. in broiler flocks, which highlights urgent need for implementing effective contol measures to reduce emergence and spread of antimicrobial resistant Campylobacters. Keywords : Thermophilic Campylobacter, Antimicrobial Resistance, Virulence, Genotyping