Prevalence of virulence-associated genes and cytolethal distending toxin production in Campylobacter spp. isolated in Italy.

The prevalence of virulence and cytolethal distending toxin (CDT) genes and the cytotoxic activity in Vero and HEp-2 cells was estimated in 29 Campylobacter jejuni and 36 Campylobacter coli from foods, animals and humans isolates. All C. jejuni showed flaA, cadF, cdtA, cdtB, cdtC and cdt cluster genes fragments, except for ceuE (86.2%) and cdt genes (93.1%). Amongst C. coli strains, a lower prevalence of ceuE gene (83.3%) was detected than that for cdtA, cdtB, cdtC genes (97.2%), cdt gene cluster (94.4%) and cdt genes (86.1%); whereas flaA and cadF genes were amplified in all isolates. Despite the high prevalence of CDT genes only 8 (27.6%) C. jejuni and 1 (2.8%) C. coli showed evidence for cytotoxin production in HEp-2 cells. However, how CDT positive and CDT negative strains differ in their biological properties remains unknown, but the relative higher prevalence of cytotoxicity in C. jejuni could be consistent with its predominant epidemiological role in human infections. (c) 2009 Elsevier Ltd. All rights reserved.