Prevalence of potential virulence markers in Polish Campylobacter jejuni and Campylobacter coli isolates obtained from hospitalized children and from chicken carcasses.

The pathogenicity of thermotolerant Campylobacter species, common food-borne pathogens, depends on certain factors unevenly distributed among strains of different origin. The prevalence of such markers has never been examined in a population of Polish Campylobacter strains of human and poultry origin. Therefore, we analysed the presence of the cadF, cdtA, cdtB and cdtC genes and the iam sequence in Campylobacter jejuni (n = 115) and Campylobacter coli (n = 57) isolates from children with diarrhoea and from chicken carcasses. The cadF gene was present in nearly 100% of Campylobacter isolates tested, regardless of their origin or species. In contrast, the iam region was found in 83.3% and 100% of C. coli isolates from children and chickens, respectively, but in only 1.6% and 54.7%, respectively, of C. jejuni isolates. Similarly, the detection rates of cdt genes varied between human and chicken isolates. All three cdt genes were found in nearly all C. jejuni isolates from both children and chickens, but in only 5.6% of human C. coli isolates as compared to 87.2% of chicken C. coli isolates. This different distribution of genetic markers between human and chicken isolates indicates that some Campylobacter infections in children may have additional sources other than contaminated chicken meat.