Vibrio cholerae is a usual inhabitant of the marine environment causes severe diarrheal disease contaminating thousands of people each year in developing countries. Cholera is still a threat to a large number of people in the universe.
Gram-negative Highly motile; polar flagellum Brackish rivers, coastal waters Associate with plankton and algae Proliferate in summers Cholera toxin Pathogenic and nonpathogenic strains 206 serogroups
Grows in salt and fresh water Can survive and multiply in brackish water by infecting copepods Has over 150 identified serotypes based on O-antigen Only O1 and O139 are toxigenic and cause Cholera disease 2 categories of O1 serotypes – Classical and El Tor
A life-threatening secretory diarrhea induced by enterotoxin secreted by V. cholerae food contaminated by copepods infected by V. cholerae An enterotoxic enteropathy (a non- invasive diarrheal disease) A major epidemic disease
Occur 2-3 days after consumption of contaminated food/water Usually mild, or no symptoms at all 75% asymptomatic 20% mild disease 2-5% severe Vomiting Cramps Watery diarrhea (1L/hour) Without treatment, death in 18 hours- several days
One hundred water samples were collected from four stations of Ahvaz Karun River. After DNA extraction, a polymeras chian reaction (PCR) assay was performed for detection of ctxA and tcpA (both Classical and ElTor variants) and OmpW was in the strain that was recognized as V. cholerae non - O139 and non - O1
The virulence of Vibrio spp. is regulated by the ctxAB and tcpA genes. These genes are supposed to be exclusively associated with clinical strains of O1 and O139 serogroups
Among 100 environmental samples of fresh water in this study, 27 isolate confirmed as V. cholerae spp. by PCR assay with ompW gene. 4 isolate that were confirmed V. cholerae non O1- non O139 had gene for toxin coregulated pilli.
2 main serogroups carry set of virulence genes necessary for pathogenesis O1 Classical: 1 case per 30-100 infections El Tor: 1 case per 2-4 infections O139 Contained in India, Bangladesh
V. cholerae is one of the major causes of morbidity and mortality in the developing countries. The studies that were performed on V. cholera nonO1, nonO139 strains that usually do not carry the ctx genes coding for cholera toxin (CT) or toxin-co regulated pilus which are the most important virulence characteristics of the cholera causing strains.
Pathogenic strains ofV. cholerae containstwo essential geneticelements, CTX element tcp geneand the vibriopathogenicity island(VPI) and toxin co-regulated pilus (TCP),respectively (Mishra et ctx geneal., 2011)
Itis believed that most of the environmental strains do not produce cholera toxin The knack of pathogenic Vibrio spp. to cause disease depends on the expression of virulence factors like a potent enterotoxin (CT), a pilus colonization factor toxin co-regulated pilus; TCP).
Cholera toxin (CT), which is responsible for the life threatening diarrheal disease cholera gravis caused by epidemic cholera (Blackstone et al., 2007). All Vibrio strains that are able of causing cholera continuously carry genes for TCP The nucleotide sequencing of OmpW gene in V. cholerae strains has unchanged among different V. cholerae strains that has made it a highly proper genetic marker for the organism (Nandy et al., 2000).
Inthis investigation, we have studied the probability of the presence of genes that cods tcpA and ctxAB in V. cholerae non O1 and non O139.
Boil or treat water with chlorine or iodine Cook everything Wash hands frequently
WHO-World Health Organization (2010). Cholera, 2009, Wkly Epidemiol. Rec., 85: 293-308. Wachsmuth IK, Blake PA, Olsvik O (1994). Vibrio cholerae and cholera: Molecular to global perspectives, Washington, DC: ASM Press, 293-295. Shimada T, Arakawa E, Itoh K (1994). Extended serotyping scheme for Vibrio cholerae. Curr. Microbiol., 28: 175- 178. Mishra A, Taneja N, Sharma RK (2011). Amplified fragment length polymorphism of clinical and environmental Vibrio cholerae from a freshwater environment in a cholera-endemic area, India Mishra et al. BMC Infectious Diseases., 11(249): 1471-2334. Faruque SM, Saha MN, Asadulghani Sack DA (2000). The O139 serogroup of Vibrio cholerae comprises diverse clones of epidemic and non-epidemic strains derived from multiple V. cholerae O1 or non-O1 progenies. J. Infect., Dis., 182: 1161–1168. Faruque SM, Nair GB (2002). Molecular ecology of toxigenic Vibrio cholerae. Microbiol. Immunol., 46: 59–66. Blackstone GM, Nordstrom JL, Bowen MD (2007). Use of a real time PCR assay for detection of the ctxA gene of Vibrio cholera in an environmental survey of Mobile Bay. J. Microbiol. Methods, 68: 254-259. Sharma A, Chaturvedi AN (2006). Prevalence of virulence genes (ctxA, stn, OmpW and tcpA) among non-O1 Vibrio cholerae isolated from fresh water environment. Int. J. Hyg. Environ. Health, 209: 521–526. Herrington DA, Hall RH, Losonsky GA (1988). Toxin, toxincoregulated pili, and the toxR regulon are essential for Vibrio cholerae pathogenesis in humans., J. Exp. Med., 168: 1487–1492 Identification of Vibrio cholerae pathogenicity island (ctxA, OmpW and tcpA) in non - O139 and non - O1 V. cholerae strains isolated from Karun River in Ahvaz, Iran Ahmad Farajzadeh Sheikh1,2, Hamed Goodarzi1* and Sajad Aslani1