Virulence characteristics of hcp+ Campylobacter jejuni and Campylobacter coli isolates from retail chicken.

Background: Recently the Type VI secretion system (T6SS), which can play a significant role in bacterial survival and pathogenesis, was reported in Campylobacter spp., having the hcp gene as a key component. Methods: Campylobacteriosis is associated with the consumption of infected chicken meat. Our study aimed to explore the presence of T6SS in C. jejuni (n = 59) and C coli (n = 57) isolates, from retail raw chicken and to investigate their pathogenic potential. The hcp gene was used as an indicator for the T6SS presence. Results: Using multiplex PCR we have identified a significantly higher prevalence of hcp in C coli isolates (56.1%) than in C. jejuni (28.8%) and AFLP analysis of the isolates showed a high degree of genetic similarity between the isolates carrying the hcp gene. Genome sequencing data showed that 84.3% of the C coli and 93.7% of the C. jejuni isolates had all 13 T6SS open reading frames. Moreover, the virulence characteristics of hcp + isolates, including motility and the ability to invade human intestinal epithelial cells in vitro, were significantly greater than in the control strain C. jejuni 12502; a human isolate which is hcp positive. Conclusion: Overall, it was discovered that hcp+ C coli and C. jejuni isolated from retail chicken isolates posses genetic and phenotypic properties associated with enhanced virulence. However, since human infections with C coli are significantly less frequent than those of C. jejuni, the relationship between virulence factors and pathogenesis requires further study. [ABSTRACT FROM AUTHOR]