Vibriophage VcA-3 as an epidemic strain marker for the U.S. Gulf Coast Vibrio cholerae O1 clone

Almeida, R J; Cameron, Daniel N.; Cook, W. L.; Wachsmuth, I K

doi:10.1128/jcm.30.2.300-304.1992

Cited by 28 publications

(12 citation statements)

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“…Strains of V. cholerae O1 apparently showing similar traits, including the lack of known virulence genes, have recently been isolated from northern Brazil and designated the Amazonian variant of pathogenic V. cholerae O1 (5). Molecular epidemiological studies have shown diversity among NT V. cholerae O1 strains (2,4) and have also shown that some of the NT strains were indistinguishable from their toxigenic counterparts (2). On the basis of the present study, it appears that there exists a clone of NT V. cholerae O1 which has the potential to cause localized outbreaks of cholera, and such strains need to be monitored carefully.…”

Section: Resultsmentioning

confidence: 56%

Nontoxigenic Vibrio cholerae 01 serotype Inaba biotype El Tor associated with a cluster of cases of cholera in southern India

et al. 1996

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Thirteen strains of Vibrio cholerae O1 belonging to the Inaba serotype El Tor biotype isolated from patients during an outbreak of cholera in the town of Warangal in southern India were found to be nontoxigenic (NT), since they did not produce cholera toxin or hybridize with DNA probes specific for cholera toxin, Zot, or Ace. The unheated and heated culture supernatants of the NT V. cholerae O1 evoked a rapid cell-rounding effect when introduced on confluent layers of CHO and HeLa cells which could not be inhibited by antiserum against known toxins. Culture supernatants of two representative NT V. cholerae O1 strains caused an increase in short-circuit current in rabbit ileal tissue mounted on an Ussing chamber, and the pattern of increase in short-circuit current was consistent with the presence of a quickly acting toxin like stable toxin. None of the strains of NT V. cholerae O1 hybridized with a DNA probe specific for the heat-stable enterotoxin of V. cholerae non-O1, nor did the factor produced by NT V. cholerae O1 resemble the recently described heat-stable enterotoxin produced by enteroaggregative Escherichia coli as determined by a PCR assay. To our knowledge, this is the first report of NT V. cholerae O1 being associated with a cluster of cases of cholera, and it appears that a clone of NT V. cholerae O1 has the potential to cause localized outbreaks of cholera.Biochemically and serologically indistinguishable strains of Vibrio cholerae belonging to the O1 serogroup which do not produce cholera toxin (CT) and which lack the toxin structural genes are currently termed as nontoxigenic (NT) strains. From time to time, NT V. cholerae O1 has been isolated from patients and from environmental sources in several countries, including Bangladesh, Guam, Brazil, Peru, Japan, England, and the United States (17). The NT strains of V. cholerae O1 have remained a scientific curiosity in the absence of a proper understanding of the mechanism of pathogenesis and also because of the lack of knowledge of what factors interplay in initiating acute secretory diarrhea. These strains are, however, important to bridge the hiatus in our knowledge of why recombinant attenuated candidate vaccine strains of V. cholerae O1 lacking all known putative toxigenic factors (21) are still able to cause residual diarrhea.The past few years have witnessed unprecedented changes in the history of cholera. Foremost among these changes was the emergence of a new serogroup causing cholera (3) classified as V. cholerae O139 Bengal (20). At the time when the O139 serogroup was in the process of rapidly spreading through vast areas of India (11), a set of strains of V. cholerae isolated from a cholera outbreak in southern India were referred to us at the National Reference Center for Cholera in Calcutta, India. Characterization of these strains revealed them to be nontoxigenic, and to our knowledge they are the first NT strains of V. cholerae O1 associated with a cluster of cases of cholera. In this study, we report the extensive characterization of ...

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Section: Resultsmentioning

confidence: 56%

Nontoxigenic Vibrio cholerae 01 serotype Inaba biotype El Tor associated with a cluster of cases of cholera in southern India

et al. 1996

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“…If the plugs were not to be used immediately, only two washes in TE were performed; this was followed by overnight incubation in 5 ml of TE at 4°C. A small portion of the plug (2 by 7 mm) was sliced off and was incubated for 1 Analysis of PFGE patterns. V. cholerae 01 isolates were separated into patterns on the basis of differences in band arrangements.…”

Section: Methodsmentioning

confidence: 99%

Molecular characterization of Vibrio cholerae O1 strains by pulsed-field gel electrophoresis

et al. 1994

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Pulsed-field gel electrophoresis (PFGE) was performed on 180 isolates of Vibrio cholerae serogroup 01 representing 6 different multilocus enzyme electrophoresis (MEE) types and 27 rRNA restriction fragment length polymorphism types (ribotypes). Isolates were digested with the restriction enzyme NotI and were separated into 63 patterns on the basis of differences in band arrangements. In general, strains which were different by MEE or ribotyping also had different PFGE patterns. PFGE identified individual strains within a single MEE type or ribotype; isolates with one PFGE pattern were less frequently distinguished by ribotyping. All V. cholerae 01 isolates tested from the Latin American epidemic were indistinguishable by their MEE, ribotype, or PFGE patterns. PFGE could further distinguish strains of this same ribotype isolated in Africa, Europe, the South Pacific, or Southeast Asia. Although both MEE and PFGE could identify the strain from the Latin American epidemic, PFGE was more rapid and less labor intensive. PFGE also distinguished nontoxigenic isolates endemic to the U.S. Gulf Coast from unrelated nontoxigenic isolates. In the present study PFGE was more discriminating than other previously described subtyping assays for V. cholerae 01 and appears to be a useful epidemiologic tool.

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“…pCTX-Kn D100 contains a 100 bp deletion but retains XerC/D Site II (Figs 1 and 3B). These two pCTX-Kn derivatives were electroporated into 2740-80, an attB + V. cholerae strain that lacks a CTX prophage (Almeida et al, 1992;Pearson et al, 1993). Integration into the natural attB site was detected by Southern blot with a CTXf probe (a fragment of pIII CTX ; Huber and Waldor, 2002) (Fig.…”

Section: Ctxf Integration Depends On An Attp Sequence Comprised Of Twmentioning

confidence: 99%

“…All V. cholerae strains used here are derivatives of 2740-80, a United States Gulf Coast natural isolate lacking a CTX prophage (Almeida et al, 1992;Pearson et al, 1993). 2740-80 Datt1 has a 28 bp deletion in the attB/dif region, which abolishes CTXf integration into the natural locus (Huber and Waldor, 2002).…”

Section: Strains and Plasmidsmentioning

confidence: 99%

Characterization of XerC‐ and XerD‐dependent CTX phage integration in Vibrio cholerae

McLeod

Waldor

2004

Molecular Microbiology

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Summary CTXφ is a filamentous bacteriophage that encodes cholera toxin and integrates site‐specifically into the larger of the two Vibrio cholerae chromosomes. The CTXφ genome lacks an integrase; instead, its integration depends on the chromosome‐encoded tyrosine recombinases XerC and XerD. During integration, recombination occurs between regions of homology in CTXφ and the V. cholerae chromosome. Here, we define the elements on the phage genome (attP ) and bacterial chromosome (attB) required for CTXφ integration. attB is a short sequence composed of one binding site for XerC and XerD spanning the site of recombination. Together, XerC and XerD bind to two sites within attP. While one XerC/D binding site in attP spans the core recombination region, the other site is ≈ 80 bp away. Although integration occurs at the core XerC/D binding site in attP, the second site is required for CTXφ integration, suggesting it performs an architectural role in the integration reaction. In vitro cleavage reactions showed that XerC and XerD are capable of cleaving attB and attP sequences; however, additional cellular processes such as DNA replication or Holliday junction resolution by a host resolvase may contribute to integration in vivo.

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Vibriophage VcA-3 as an epidemic strain marker for the U.S. Gulf Coast Vibrio cholerae O1 clone

Cited by 28 publications

References 20 publications

Nontoxigenic Vibrio cholerae 01 serotype Inaba biotype El Tor associated with a cluster of cases of cholera in southern India

Nontoxigenic Vibrio cholerae 01 serotype Inaba biotype El Tor associated with a cluster of cases of cholera in southern India

Molecular characterization of Vibrio cholerae O1 strains by pulsed-field gel electrophoresis

Characterization of XerC‐ and XerD‐dependent CTX phage integration in Vibrio cholerae

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