Frequency Analysis of Genes ctxA, tcpA, Ace and Zot in Vibrio Cholerae Isolated of Epidemy of Summer 2005 in Iran By PCR

V. cholerae, a Gram-negative bacterium is the causative agent of Cholera. V. cholerae O1 produces cholera toxin (CT) which is responsible for diarrhea. The zonula occludens toxin (Zot) acts on intestinal tight junctions to increase intestinal permeability. The accessory cholera enterotoxin (Ace) increases the potential difference across intestinal epithelium and alters ion transport. V. cholerae athogenicity depends on a combination of factors known as ability to produce a cholera toxin (CT) and to adhere and colonize small intestine through colonization factor known as toxin-coregulatedpilus (TCP). Thirty nine El Tor variants were obtained from outbreaks during 2005 in Iran. After detection of isolates by biochemical methods, and serotyping, chromosomal DNA was extracted by standard phenol/chloroform method. The oligonucleotide primers for each of the selected virulence-associated factors were designed based on available GenBank sequences for V. cholerae O1 E1 Tor for all the genes. PCR assay was performed and the PCR product was run and visualized in 1.5% agarose gels stained with ethidium bromide. In the present study, PCR was used to detect the presence of ctxA, Zot, Ace, and tcpA genes on 39 V. cholerae strains isolated from the summer epidemic 2005 in Iran. With the specific primers, the V. cholerae isolates were analysed by PCR for the presence of tcpA, ctxA, Ace and Zot genes. PCR showed that the genes encoding cholera toxin (ctxA), toxin co-regulated pilus (tcpA), accessory cholera enterotoxin (Ace) and zonula occludens toxin (Zot) were present in 89.74%, 84.6%, 100% and 100% of the isolates, respectively. Discussion & The results of our study confirm that strains without ctxA gene, Ace and Zot genes are important and can be the causative agent of cholera.