APPEARANCE OF TOXICOGENIC VIBRIO-CHOLERAE STRAINS OF NON-O1 SEROTYPE AS A RESULT OF GENETIC EXCHANGE

To study the possibilities of genetic exchange between Vibrio cholerae of O1 and non-O1 serogroups, donor and recipient strains were develop ed. It was shown that toxicogenic strains of V. cholerae non-O1 appear ed in vitro and in vivo as the result of conjugative transfer of rfb-N AG genes from avirulent V. cholerae non-O1 strains to toxicogenic stra ins belonging to V. cholerae O1 classical and eltor biovars. These gen es are responsible for synthesis of O antigen of non-O1 serotype. It w as established that foreign rfb-NAG genes have no effect on virulence properties of a causative agent of cholera. Apparently, pathogenic V. cholerae non-O1 strains with cholera toxin genes are generated due to transfer of rfb-NAG genes under natural conditions.