GENE FOR THE ENTEROTOXIN ZONULA-OCCLUDENS TOXIN IS PRESENT IN VIBRIO-MIMICUS AND VIBRIO-CHOLERAE-O139

The presence of the zonula occludens toxin (ZOT) gene, which encodes a n enterotoxin produced by serotype O1 strains of the pathogenic bacter ium, Vibrio cholerae, in addition to cholera toxin, was investigated i n selected strains of V. mimicus and the new pandemic V. cholerae non- Ol serotype O139. The zot gene was detected by polymerase chain reacti on (PCR) amplification, using sets of primers based on the sequence of the V. cholerae O1 rot sequence. PCR amplification of genomic DNAs of both cholera toxin gene (ctx) positive and ctx(-) strains of V. mimic us detected the presence of zot gene. An AccI-EcoRV V. cholerae zot ge ne fragment designed to overlap PCR products was used as a probe. Sout hern hybridization studies confirmed that the PCR fragments from V. mi micus and V. cholerae O139 were strongly homologous to the V. cholerae O1 zot gene. The zot gene was found with 3 of 5 strains of V. mimicus of which only one strain harbored the ctx gene. The presence of a zot gene in ctx(-) toxigenic V. mimicus indicates a possible role of ZOT in the toxigenicity of this species. We conclude that, in addition to ctx, V. mimicus and V. cholerae O139 have the potential to produce ZOT .