Vibrio cholerae Colonization of Soft-Shelled Turtles

Vibrio cholerae is an important human pathogen and environmental microflora species that can both propagate in the human intestine and proliferate in zooplankton and aquatic organisms. Cholera is transmitted through food and water. In recent years, outbreaks caused by V. cholerae -contaminated soft-shelled turtles, mainly of toxigenic serogroup O139, have been frequently reported, posing a new foodborne disease public health problem. In this study, the colonization of toxigenic V. cholerae on the body surface and intestine of the soft-shelled turtle was explored. Preferred colonization sites on the turtle body surface, mainly the carapace and calipash of the dorsal side, were observed for the O139 and O1 strains. Intestinal colonization was also found. The colonization factors of V. cholerae played different roles in colonization of the soft-shelled turtle body surface and intestine. Mannose-sensitive hemagglutinin (MSHA) of V. cholerae was necessary for body surface colonization, but no roles were found for toxin-coregulated pili (TCP) and N-acetyl glucosamine-binding protein A (GBPA). Both TCP and GBPA play important colonization roles in the intestine, whereas the deletion of MSHA identified only a minor colonization-promoting role for this factor. Our study demonstrated that V. cholerae could colonize the surface and the intestines of soft-shelled turtles and indicated that the soft-shelled turtles played a role in the transmission of cholera. In addition, this study showed that the soft-shelled turtle has potential value as an animal model in studies of the colonization and environmental adaption mechanisms of V. cholerae in aquatic organisms. IMPORTANCE Cholera is transmitted through water and food. Vibrio cholerae (commonly the serogroup O139 strains) contaminated soft-shelled turtles have caused many foodborne infections and outbreaks in recent years, and this organism has become a foodborne disease problem. Except for epidemiological investigations, no experimental studies have demonstrated the colonization of V. cholerae on soft-shelled turtles. These studies will benefit our understanding of the interaction between V. cholerae and the soft-shelled turtle. We demonstrated the colonization of V. cholerae on the soft-shelled turtle9s body surface and in the intestine and revealed the different roles of major V. cholerae colonization factors on the body surface and in the intestine. Our work provides experimental evidence for the role of soft-shelled turtles in cholera transmission. In addition, this study also shows the possibility for the soft-shelled turtle to serve as a new animal model for studying the interaction between V. cholerae and aquatic hosts.