Year: 2026
Type: article
Abstract: BACKGROUND: The survival of various strains of Vibrio cholerae in water bodies contaminated with heavy metals, particularly cadmium, poses a threat to public health. Of particular interest is the study of the role of biofilms formed by V. cholerae on chitin in this process. АIM: To investigate the role of complex biofilms formed on chitin as a factor in the persistence of toxigenic and non-toxigenic V. cholerae under the toxic effects of cadmium. METHODS: The study used V. cholerae El Tor O1 toxigenic 5342 ctxA+ csh1- strain isolated from a human in 2023 and non-toxigenic 643 ctxA- csh1+ strain isolated from the Matsesta River (Sochi) in 2025, representing a "persistent" genotype repeatedly isolated from the rivers of Sochi. The formation of complex biofilms by two strains was carried out on chitin fragments, and the viability was determined by seeding the corresponding material on Martin's agar. The presence of molecular markers ctxA and csh1 was determined using multiplex real-time polymerase chain reaction (PCR). The effect of cadmium Cd on the formation stage and mature biofilm was studied by adding it to the incubation medium at the appropriate time. RESULTS: Without external influence, both strains were capable of forming a complex biofilm on chitin. The non-toxic strain 643 adhered and formed a biofilm in the presence of 0.01 mM and 0.05 mM cadmium, while the adhesion of the toxic strain was completely inhibited under these conditions. In the case of a mature complex biofilm, both strains retained their viability in the biofilm and supernatant even when exposed to known toxic concentrations of heavy metal (up to 0.6 mM). CONCLUSION: The obtained results indicate that the mature V. cholerae biofilm formed on a chitin substrate ensures the viability of the pathogen when exposed to Cd concentrations that are lethal for planktonic forms. The differences in the response of the toxigenic and non-toxigenic persistent strains of V. cholerae to the toxic effects of Cd during the adhesion stage may reflect the specific features of their ecological adaptation.
DOI: 10.17816/eid706269
Institution: Rostov-on-Don Anti-plague Institute Rospotrebnadzor
Language: English
Subfield: Microbiology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7220868626