PCR Detection of Four Virulence-Associated Genes of Campylobacter jejuni Isolates from Thai Broilers and Their Abilities of Adhesion to and Invasion of INT-407 Cells

Campylobacter jejuni is a major cause of food borne pathogens in humans and a major reservoir for this pathogen is poultry. The C. jejuni in broilers was investigated from in the caeca of broilers. Twenty broiler/flock samples from 7 flocks were assessed. The average prevalence of C. jejuni was 65% in the broiler flocks. The adhesion and invasion ability of 48 strains of C jejuni on INT 407 were studied. The adhesion and invasion ability of 48 Campylobacter isolates from caecal contents were analyzed with Human embryonic intestine (INT-407) cells being used as a gentamicin resistance assay. The caecal isolates exhibited a wide range of adherence and invasion ability. There was a significant correlation (p<0.01) between the adherence and the invasion ability of the Campylobacter isolates. Each of the virulence-associated genes: dnaJ, cadF, pldA and ciaB was detected by polymerase chain reaction from 100, 76, 3 1 and 41% of the Campylobacter strains, respectively. All of four virulence-associated genes were detected in 11 isolates. However, there was unclear association between the invasion ability and the presence of virulence-associated genes in this experiment, suggesting that more genes may be involved in the invasion process.