Variation in epitopes of the B subunit of <i>Vibrio cholerae</i> non-O1 and <i>Vibrio mimicus</i> cholera toxins

Tamplin, Mark L.; Jalali, Reema; Ahmed, Mohammed K.; Colwell, Rita R.

doi:10.1139/m90-071

Cited by 8 publications

(3 citation statements)

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“…Thus, in effect, the present El Tor biotype strains produce CT of the classical biotype. The production of classical CT by the El Tor biotype per se is not novel and has been reported infrequently (1,11,17). In fact, U.S. Gulf Coast clones of V. cholerae O1 are El Tor strains that possess the classical CT (12).…”

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Cholera Due to Altered El Tor Strains of Vibrio cholerae O1 in Bangladesh

et al. 2006

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We determined the types of cholera toxin (CT) produced by a collection of 185 Vibrio cholerae O1 strains isolated in Bangladesh over the past 45 years. All of the El Tor strains of V. cholerae O1 isolated since 2001 produced CT of the classical biotype, while those isolated before 2001 produced CT of the El Tor biotype.Vibrio cholerae O1 has two biotypes, namely, classical and El Tor, which are believed to have evolved from separate lineages (7,8), and these biotypes have traditionally been differentiated by a number of phenotypic traits. Comparative genomic analyses have recently revealed a high degree of conservation among diverse strains of V. cholerae but have also shown genes that differentiate the classical biotype from the El Tor biotype (3). Apart from these phenotypic and genetic differences, there are also dissimilarities in the infection patterns of disease caused by the two biotypes. These include the occurrence of more asymptomatic than symptomatic carriers of El Tor strains, who outnumber active patients by a ratio of up to 50:1 (14), better survival of El Tor strains in the environment and in the human host, and more efficient host-to-host transmission of El Tor strains than of classical strains (5). There is firm evidence that the fifth and sixth pandemics of cholera were caused by the classical biotype, while the ongoing seventh pandemic is caused by the El Tor biotype, which has now globally replaced the classical biotype.Cholera toxin (CT), the principal toxin produced by V. cholerae O1 and O139, is responsible for most of the manifestations of the disease cholera. Based on the B subunit of CT, two immunologically related but not identical epitypes have been described: CT1 is the prototype elaborated by classical biotype strains and by U.S. Gulf Coast strains, while CT2 is produced by the El Tor biotype and O139 strains (4). Another classification identifies three types of ctxB genes based on three nonrandom base changes resulting in changes in the deduced amino acid sequence. Genotype 1 is found in strains of the classical biotype worldwide and in U.S. Gulf Coast strains, genotype 2 is found in El Tor biotype strains from Australia, and genotype 3 is found in El Tor biotype strains from the seventh pandemic and the Latin American epidemic (12). Thus, the V. cholerae O1 El Tor biotype of the ongoing seventh pandemic produces CT of the CT2 epitype and genotype 3, while the classical biotype CT belongs to the CT1 epitype and genotype 1. In this study, we examined a collection of clinical V. cholerae O1 strains isolated in Bangladesh during the past four and a half decades, using monoclonal antibodies (MAbs) produced to classical and El Tor CTs, and found that V. cholerae O1 El Tor strains isolated since 2001 in Bangladesh produce the CT subtype of the classical biotype.One hundred eighty-five strains of V. cholerae O1, consisting of 31 strains of the classical biotype isolated between 1960 and 1990 and 113 strains of the El Tor biotype and 41 hybrid strains of V. cholerae O1 (strains that could ...

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Cholera Due to Altered El Tor Strains of Vibrio cholerae O1 in Bangladesh

et al. 2006

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“…It has been shown that some V. mimicus strains are able to produce a heat-labile enterotoxin, functionally and immunobiologically related to the heat-labile CT (12,22), as well as other toxins and toxic substances that might contribute to its pathogenesis (5,7,8,12). Nevertheless, as in the case of V. cholerae O1, CT is probably the main factor responsible for the severity of this diarrhea.…”

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confidence: 99%

“…Toxigenicity assays. V. mimicus strains were studied for heat-labile CT production by enzyme-linked immunosorbent assay (ELISA) using monoclonal antibody CT-1 (CT-B), which was kindly provided by M. L. Tamplin, University of Florida (22), and/or by the Y-1 adrenal cell assay (11). Thirty-nine isolated strains were tested for the presence of the ctxA gene by PCR using primers Col-1 (5Ј-CTCAGACGGGATTTGTTAGGCACG-3Ј, positions 197 to 220) and Col-2 (5Ј-TCTATCTCTGTAGCCCCTATTACG-3Ј, positions 475 to 498), provided by L. M. Sánchez, University of Stanford at Mexico, by the procedure described by Shirai et al (20).…”

Section: Methodsmentioning

confidence: 99%

Vibrio mimicus diarrhea following ingestion of raw turtle eggs

Campos

Bolaños

Acuña

et al. 1996

Appl Environ Microbiol

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Clinical and epidemiological characteristics of diarrhea associated with Vibrio mimicus were identified in 33 hospitalized patients referred to the Costa Rican National Diagnostic Laboratory Network between 1991 and 1994. The relevant symptoms presented by patients included abundant watery diarrhea, vomiting, and severe dehydration that required intravenous Dhaka solution in 83% of patients but not fever. Seroconversion against V. mimicus was demonstrated in four patients, from whom acute-and convalescent-phase sera were obtained. Those sera did not show cross-reaction when tested against Vibrio cholerae O1 strain VC-12. All the V. mimicus isolates from these cases produced cholera toxin (CT) and were susceptible to commonly used antibiotics. Attempts to isolate this bacterium from stool samples of 127 healthy persons were not successful. Consumption of raw turtle eggs was recalled by 11 of the 19 (58%) individuals interviewed. All but two V. mimicus diarrheal cases were sporadic. These two had a history of a common source of turtle (Lepidochelys olivacea) eggs for consumption, and V. mimicus was isolated from eggs from the same source (a local market). Among the strains, variations in the antimicrobial susceptibility pattern were observed. None of the strains recovered from market turtle eggs nor the four isolates from river water showed CT production. Further efforts to demonstrate the presence of CT-producing V. mimicus strains in turtle eggs were made. Successful results were obtained when nest eggs were tested. In this case, it was possible to isolate CT-and non-CT-producing strains, even from the same egg. For CT detection we used PCR, enzyme-linked immunosorbent assay (ELISA), and Y-1 cell assay, obtaining a 100% correlation between ELISA and PCR results. Primers Col-1 and Col-2, originally described as specific for the V. cholerae O1 ctxA gene, also amplified a 302-bp segment with an identical restriction map from V. mimicus. These results have important implications for epidemiological surveillance in tropical countries where turtle eggs are used for human consumption, serving as potential sources of cholera-like diarrhea.

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Foodborne Pathogenic Vibrios

Ramamurthy

Nair

Infectious Disease

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Variation in epitopes of the B subunit of Vibrio cholerae non-O1 and Vibrio mimicus cholera toxins

Cited by 8 publications

References 18 publications

Cholera Due to Altered El Tor Strains of Vibrio cholerae O1 in Bangladesh

Cholera Due to Altered El Tor Strains of Vibrio cholerae O1 in Bangladesh

Vibrio mimicus diarrhea following ingestion of raw turtle eggs

Foodborne Pathogenic Vibrios

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