DETECTION OF CHOLERA (CTX) AND ZONULA OCCLUDENS (ZOT) TOXIN GENES IN VIBRIO-CHOLERAE O1, O139 AND NON-O1 STRAINS

Vibrio choleuae O1 and V. cholerae non-O1 strains isolated from enviro nmental samples collected in Sao Paulo, Brazil, during cholera epidemi cs and pre-epidemic periods were examined for the presence of toxin ge nes, V. cholerae O1 strains isolated from clinical samples in Peru and Mexico, and V. cholerae O139 strains from India were also examined fo r the presence of ctx (cholera toxin gene) and tot (zonula occludens t oxin gene) by polymerase chain reaction (PCR). A modified DNA-extracti on method applied in this study yielded satisfactory recovery of genom ic DNA from vibrios. Results showed that strains of V. cholerae 01 iso lated during the preepidemic period were ctx(-)/zot(-) whereas strains isolated during the epidemic were cfx(+)/zot(+). All V. cholerae non- O1 strains tested in the study were ctx(-)/zot(-), whereas all V. chol erae O139 strains were ctx(+)/zot(+) Rapid detection of the virulence genes (ctx and to) can be achieved by PCR and this can serve as an imp ortant tool in the epidemiology and surveillance of V. cholerae.