HlyA hap toxR tcpI tcpA rtxA vasA vasK vasH vcsN vcsC HlyA hap ctxA toxR tcpI rtxA vasA vasK vasH vcsN vcsV vcsC HlyA hap toxR tcpI rtxA vasA vasK vasH vcsN vcsV vcsC Hap ctxA zot toxR tcpI rtxA vasA vasK vasH HlyA hap zot toxR tcpI rtxA vasA vasK vasH HlyA hap zot toxR tcpI tcpA rtxA vasA vasK vasH HlyA hap toxR rtxA vasA vasK vasH vcsV vcsC HlyA hap ctxA zot toxR tcpI rtxA vasA vasK vasH HlyA hap ctxA zot toxR tcpI tcpA rtxA vasA vasK vasH cholerae O139 isolates and 601 environmental V. cholerae O1 isolates, as well as 10 clinical and 31 environmental V. The strain collection comprised 102 clinical and 50 environmental V. cholerae strains ( Table 1) isolated during epidemiological and ecological surveillance in the provinces of Bakerganj and Mathbaria, Bangladesh, between 20, with details described elsewhere ( 21). The aim of this study was to determine the presence of virulence-associated factors in 794 V. Occasionally, cholera toxin ( ctxA) ( 15) and toxin-coregulated-pilus-associated genes ( tcpA and tcpI) ( 20) have been reported in V. Similarly, nontoxigenic Vibrio cholerae O1 has been linked to gastroenteritis ( 10) and localized cholera outbreaks ( 11).Ī range of putative virulence factors has been described, including hemolysin ( hlyA) ( 12), non-O1 (NAG-ST) and O1 (O1-ST) heat-stable enterotoxins (encoded by stn and sto genes, respectively) ( 13), ToxR ( toxR) ( 14), zonula occludens toxin ( zot) ( 15), actin cross-linking repeats in toxin ( rtxA) ( 16), hemagglutinin protease ( hap) ( 17), the type VI secretion system (T6SS) ( 18), and the type III secretion system (T3SS) ( 19). For 30 years, they have been associated with septicemia ( 4, 5), peritonitis ( 6), and gastroenteritis ( 7– 9), via ingestion of contaminated food or exposure to the aquatic environment. cholerae strains inhabit estuarine and coastal waters, but their clinical significance is underappreciated. The pathogenicity of serogroups O1 and O139 is associated with expression of cholera toxin (CT), encoded in the genome of a filamentous bacteriophage, CTXΦ ( 2), and the ability to adhere to the intestine via type IV pilus (toxin-coregulated pilus ) functioning as a colonization factor encoded by a pathogenicity island ( Vibrio pathogenicity island ) ( 3).
More than 200 serogroups have been described, but only serogroups O1 and O139 are linked to epidemic cholera worldwide ( 1). cholerae is present in its pathogenic form or at high densities. Since cholera is impossible to eradicate, it is crucial to continuously monitor the environment in order to minimize or prevent infections when V. It is a common member of natural aquatic environments, and the ocean serves as the principal reservoir for this organism in nature. Vibrio cholerae, the etiological agent of cholera, is a serious health threat in developing countries.