In vitro virulence factors of Arcobacter butzleri strains isolated from superficial water samples

Eighteen isolates of A. butzleri from river water samples were examined for their biotype, serogroup and putative virulence characteristics. Toxin profiles based on cytotonic, cytotoxic and cytolethal distending factors were determined after analysis responses in Vero and CHO cells. Adhesivity and invasivity tests were performed on HeLa and Intestine 407 cells. Six biotypes and five serogroups were determined in our isolates. All strains but one induced cytotoxic effects on cells in culture. The cytotoxic negative strain caused elongation of CHO cells (a cytotonic-like effect). This strain was the only one which adhered to cells in vitro. Invasiveness was never observed. Our results show a phenotypic heterogeneity of arcobacters isolated from environmental sources, and indicate that some strains could be potentially virulent.