title: Phenotypic and genetic characteristics of Vibrio cholerae O1 carrying Haitian ctxB and attributes of classical and El Tor biotypes isolated from Silvassa, India.
abstract: Vibrio cholerae O1 biotype El Tor, the causative agent of the seventh pandemic, has recently been replaced by strains carrying classical and Haitian ctxB in India, Haiti and other parts of the world.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 tcpAET and rstRET, 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.
authors.affiliation: Department of Infectious Disease Biology, Institute of Life Sciences, Nalco Square, Bhubaneswar 751023, India.
authors.forename: Moon Moon
authors.initials: MM
authors.lastname: Das
authors.affiliation: Department of Infectious Disease Biology, Institute of Life Sciences, Nalco Square, Bhubaneswar 751023, India.
authors.forename: Tilothama
authors.initials: T
authors.lastname: Bhotra
authors.affiliation: Department of Microbiology, Shri Vinoba Bhave Civil Hospital, Silvassa 396230, India.
authors.forename: Dolatsinh
authors.initials: D
authors.lastname: Zala
authors.affiliation: Department of Infectious Disease Biology, Institute of Life Sciences, Nalco Square, Bhubaneswar 751023, India.
authors.forename: Durg Vijai
authors.initials: DV
authors.lastname: Singh
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics; D015373:Bacterial Typing Techniques; D018441:Biofilms / Q000254:growth & development; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology*; D002772:Cholera Toxin / Q000235:genetics* / Q000378:metabolism; D016172:DNA Fingerprinting; D016521:Electrophoresis, Gel, Pulsed-Field; D005809:Genes, Regulator; D014644:Genetic Variation; D044404:Genomic Islands; D005838:Genotype; D006801:Humans; D007194:India / Q000453:epidemiology; D017720:Molecular Epidemiology; D058889:Molecular Typing; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D041241:Vibrio cholerae O1 / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D018829:Adhesins, Bacterial; D037521:Virulence Factors; D002772:Cholera Toxin