PCR detection of seven virulence and toxin genes of Campylobacter jejuni and Campylobacter coli isolates from Danish pigs and cattle and cytolethal distending toxin production of the isolates

Abstract

Aims: To study the prevalence of seven virulence and toxin genes, and cytolethal distending toxin (CDT) production of Campylobacter jejuni and C. coli isolates from Danish pigs and cattle.

Methods and results: The presence of the cadF, ceuE, virB11, flaA, cdtA, cdtB, cdtC and the cdt gene cluster among 40 C. jejuni and C. coli isolates was detected by polymerase chain reaction. The CDT production of the isolates was determined on Vero, colon 205 and chicken embryo cells. The cadF, flaA, ceuE and cdtB genes were detected from 100% of the isolates. The cdtA and cdtC genes were found in 95.0 and 90.0% of the isolates, respectively. The cdt gene cluster was detected in 82.5% isolates. Only 7.5% of the isolates were positive for virB11. Ninety-five per cent of the isolates produced CDT in Vero and colon 205 cell assays, and 90% of the isolates produced CDT in chicken embryo cell assays.

Conclusions: High prevalence of the cadF, ceuE, flaA and cdtB genes was found. Data of the prevalence of cdt genes was consistent with the CDT titres produced by the isolates. Campylobacter coli from pigs produced high CDT titres.

Significance and impact of the study: The high prevalence of seven virulence and toxin genes demonstrated that these putative pathogenic determinants are widespread among Campylobacter isolates from pigs and cattle. Campylobacter coli isolates from pigs produced much higher CDT titres compared with C. coli isolates from other sources suggesting that C. coli may be particularly adapted to or associated with this species.