ClassicalctxBinVibrio choleraeO1, Kolkata, India

Raychoudhuri, Amit; Patra, Tapas; Ghosh, Kausik; Ramamurthy, Thandavarayan; Nandy, Ranjan K.; Takeda, Yoshifumi; Nair, G. Balakrish; Mukhopadhyay, Asish K.

doi:10.3201/eid1501.080543

Cited by 92 publications

(83 citation statements)

References 9 publications

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“…However, the majority of isolates showing mixed phenotype traits had Haitian ctxB. Several workers also reported that strains showing mixed phenotype but genetically containing tcpA ET and rstR ET were designated hybrid El Tor variant, and those strains that showed typical features of El Tor biotype but carried the classical ctxB or classical biotype but carried the El Tor ctxB were designated as El Tor variant (Na-Ubol et al, 2011;Raychoudhuri et al, 2009;Safa et al, 2010). To the best of our knowledge, we are the first to report the presence of V. cholerae O1 with mixed phenotypes possessing the Haitian ctxB in Silvassa, western India, herewith referred to as a hybrid variant.…”

Section: Discussionmentioning

confidence: 99%

Phenotypic and genetic characteristics of Vibrio cholerae O1 carrying Haitian ctxB and attributes of classical and El Tor biotypes isolated from Silvassa, India

Das

Bhotra

Zala³

et al. 2016

Journal of Medical Microbiology

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Vibrio cholerae O1 biotype El Tor, the causative agent of the seventh pandemic, has recently been replaced by strains carrying classical and Haitian ctxB in India, Haiti and other parts of the world. We conducted phenotypic and genetic tests to characterize V. cholerae O1 isolated between 2012 and 2014 from Silvassa, India, to examine the presence of virulence and regulatory genes, seventh pandemic marker, ctxB type and biofilm formation and to study genomic diversity. Of the 59 V. cholerae O1, eight isolates belong to El Tor prototype, one to classical prototype and the remaining isolates have attributes of both classical and El Tor biotypes. PCR and ctxB gene sequencing revealed the presence of classical ctxB in four strains and Haitian ctxB in 55 isolates; indicating that isolates were either an El Tor or hybrid variant. All isolates carried virulence, regulatory, adherence, Vibrio seventh pandemic pathogenicity island I and seventh pandemic group-specific marker VC2346, in addition to tcpA ET and rstR ET , the features of seventh pandemic strains, and produced cholera toxin and biofilm. PFGE analysis showed that the majority of isolates are clonal and belong to fingerprint pattern A; however, pattern B is unrelated and patterns C and D are distinct, suggesting considerable diversity in the genomic content among them. These data thus show that isolates from Silvassa are genetically diverse and that Haitian ctxB and hybrid phenotypes are undergoing global dissemination.

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Section: Discussionmentioning

confidence: 99%

Phenotypic and genetic characteristics of Vibrio cholerae O1 carrying Haitian ctxB and attributes of classical and El Tor biotypes isolated from Silvassa, India

Das

Bhotra

Zala³

et al. 2016

Journal of Medical Microbiology

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“…Correspondingly, the sequencing of the genome of several V. cholerae strains revealed the presence of tandem copies of the classical phage (El Tor strains BX330286 and B33) (4). In addition, it was observed that classical copies of the phage coexist with intact El Tor copies and/or with the RS1 element in other strains (4,14); such coexistence also could ensure the production of classical CTXϕ virions. Interestingly, the conjunct production of El Tor and classical phages could favor the emergence of hybrid phages, a phenomenon that has been observed recently (Fig.…”

Section: Discussionmentioning

confidence: 98%

“…1C). Nevertheless, the classical variant of CTXϕ was found integrated at dif2 in classical strains (3) and in recent El Tor isolates (4,(10)(11)(12)(13)(14). The mode of dissemination of this variant is of particular interest, because it allows the production of an elevated amount of cholera toxin (15,16) that seems to be implicated in a high proportion of severe infections associated with classical strains (17).…”

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confidence: 99%

Molecular keys of the tropism of integration of the cholera toxin phage

Das

Bischerour

Val

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

109

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International audienceCholera toxin is encoded in the genome of CTXvarphi, a lysogenic filamentous phage of Vibrio cholerae. CTXvarphi variants contribute to the genetic diversity of cholera epidemic strains. It has been shown that the El Tor variant of CTXvarphi hijacks XerC and XerD, two host-encoded tyrosine recombinases that normally function to resolve chromosome dimers, to integrate at dif1, the dimer resolution site of the larger of the two V. cholerae chromosomes. However, the exact mechanism of integration of CTXvarphi and the rules governing its integration remained puzzling, with phage variants integrated at either or both dimer resolution sites of the two V. cholerae chromosomes. We designed a genetic system to determine experimentally the tropism of integration of CTXvarphi and thus define rules of compatibility between phage variants and dimer resolution sites. We then showed in vitro how these rules are explained by the direct integration of the single-stranded phage genome into the double-stranded bacterial genome. Finally, we showed how the evolution of phage attachment and chromosome dimer resolution sites contributes to the generation of genetic diversity among cholera epidemic strains

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“…and Re-elt (5?-CCTGGTACTTCTACTTGAAACA-3? ), for classical and El Tor biotypes, respectively (21,22).…”

Section: Methodsmentioning

confidence: 99%

Outbreak of Cholera Caused by Vibrio cholerae O1 El Tor Variant Strain in Bihar, India

et al. 2014

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SUMMARY: An outbreak of cholera struck Bihar, an Indian state, in August 2008 following a massive flood. Here we report the phenotypic and genotypic characteristics of Vibrio cholerae strains isolated from patients with diarrhea. Rectal swabs were obtained from patients with diarrhea who were admitted to medical camps or the hospital, and the strains were biochemically and serologically characterized. V. cholerae was isolated from 21 (65.6z) of 32 rectal swabs. Serological studies revealed that all the 21 isolates belonged to V. cholerae O1 Ogawa. Mismatch amplification mutation assay (MAMA)-PCR showed that the isolates belonged to El Tor variant group, and pulsed-field gel electrophoresis (PFGE) proved that these isolates were of a different lineage than the conventional El Tor variant strains. These isolates were resistant to several drugs, including ampicillin, streptomycin, tetracycline, nalidixic acid, and furazolidone. The uniqueness of the current report arises from the fact that records of cholera in Bihar are availiable for the early 1960s but not for the next 4 decades. Moreover, the present study is the first to report a cholera outbreak in Bihar that was caused by an El Tor variant strain.

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ClassicalctxBinVibrio choleraeO1, Kolkata, India

Cited by 92 publications

References 9 publications

Phenotypic and genetic characteristics of Vibrio cholerae O1 carrying Haitian ctxB and attributes of classical and El Tor biotypes isolated from Silvassa, India

Phenotypic and genetic characteristics of Vibrio cholerae O1 carrying Haitian ctxB and attributes of classical and El Tor biotypes isolated from Silvassa, India

Molecular keys of the tropism of integration of the cholera toxin phage

Outbreak of Cholera Caused by <i>Vibrio cholerae</i> O1 El Tor Variant Strain in Bihar, India

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