title: A large cholera outbreak due to a new cholera toxin variant of the Vibrio cholerae O1 El Tor biotype in Orissa, Eastern India.
abstract: A total of 32 Vibrio cholerae isolates were collected during a recent large cholera outbreak in Eastern India. Biochemical and serological studies revealed that all of the isolates belonged to serogroup O1, biotype El Tor, serotype Ogawa. Two multiplex PCR assays confirmed the presence of various toxigenic and pathogenic genes - ace, ctxAB, hlyA, ompU, ompW, rfbO1, rtx, tcp, toxR and zot - in all of the isolates. Sequencing of the ctxB gene from the isolates revealed a novel mutation in the gene. Sequencing also confirmed the presence of altered cholera toxin B of the classical biotype in all of the El Tor isolates, suggesting infection of isolates by classical CTXPhi. The molecular diversity of V. cholerae isolates studied by enterobacterial repetitive intergenic consensus sequence PCR, BOX-PCR and randomly amplified polymorphic DNA analysis uniformly showed the clonal relationship among the outbreak V. cholerae O1 isolates. The results of this study suggest that cholera-causing V. cholerae strains are constantly evolving in epidemic areas, highlighting the potential of the emergence of more virulent strains.
authors.affiliation: Biotechnology Division, Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior 474002, India.
authors.forename: P
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Biotechnology Division, Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior 474002, India.
authors.forename: M
authors.initials: M
authors.lastname: Jain
authors.affiliation: Biotechnology Division, Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior 474002, India.
authors.forename: A K
authors.initials: AK
authors.lastname: Goel
authors.affiliation: Biotechnology Division, Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior 474002, India.
authors.forename: S
authors.initials: S
authors.lastname: Bhadauria
authors.affiliation: Biotechnology Division, Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior 474002, India.
authors.forename: S K
authors.initials: SK
authors.lastname: Sharma
authors.affiliation: Biotechnology Division, Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior 474002, India.
authors.forename: D V
authors.initials: DV
authors.lastname: Kamboj
authors.affiliation: Biotechnology Division, Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior 474002, India.
authors.forename: L
authors.initials: L
authors.lastname: Singh
authors.affiliation: National Institute of Cholera and Enteric Diseases, Kolkata, India.
authors.forename: T
authors.initials: T
authors.lastname: Ramamurthy
authors.affiliation: National Institute of Cholera and Enteric Diseases, Kolkata, India.
authors.forename: G B
authors.initials: GB
authors.lastname: Nair
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002771:Cholera / Q000453:epidemiology* / Q000382:microbiology*; D002772:Cholera Toxin / Q000096:biosynthesis* / Q000235:genetics; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004196:Disease Outbreaks; D005838:Genotype; D006801:Humans; D007194:India / Q000453:epidemiology; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D016133:Polymerase Chain Reaction / Q000379:methods; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D041241:Vibrio cholerae O1 / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D037521:Virulence Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D037521:Virulence Factors; D002772:Cholera Toxin