The mechanism of pathogenic Vibrio cholerae to cause disease depends on the expression of virulence factors such as a potent cholera toxin (CT), and pilus colonization factor (toxin co-regulated pilus; TCP). The gene’s molecular characterization provides V. choleraeecology of the genes information about the ecology of V. cholerae which is an autochthonous inhabitant of aquatic environment as well as pathogenic for humans. ThectxAB and tcpA genes are known to play a significant role in maintaining virulence in V.cholerae, and these genes are believed to be exclusively associated with clinical strains of O1 and O139 serogroups. In this study, we examined the presence of virulence genes, including ctxA and tcpA (Classical and El Tor), as well as toxR and the genes responsible for O-antigen biosynthesis and for generation of serotype-specific determinants located in the rfb region in the V. cholerae chromosome. Out of 23 suspected V. cholerae isolated from Arabian Gulf coastal water of the eastern province of Saudi Arabia only one isolate was detected and harbored tcpA (El Tor), O1rfb and toxR genes. This study demonstrates the transfer of virulence genes among environmental strains of V. cholerae which appears to constitute an environmental reservoir of virulence genes, thereby providing new insights into the V. cholerae ecology. To the best of our knowledge, this is the first report of the isolation of V. cholerae from Arabian Gulf coastal water environment.

Key words: Vibrio cholerae non-O1/non-O139, virulence genes, PCR, Arabian Gulf water.