title: Molecular characterization reveals involvement of altered El Tor biotype Vibrio cholerae O1 strains in cholera outbreak at Hyderabad, India.
abstract: Thirty-four Vibrio cholerae isolates collected from a cholera outbreak in Hyderabad, South India were found to belong to serogroup Ol biotype El Tor serotype Ogawa. The genotype of all the isolates was confirmed by PCR assays. All the isolates were found PCR positive for ctxAB, ompW, rflOl, rtxC, and tcpA genes. All the isolates but one harboured rstR ( El Tor ) allele. However, one isolate carried both rstR ( EL Tor ) as well as rstR ( Classical ) alleles. Cholera toxin (ctxB) genotyping of the isolates confirmed the presence of altered cholera toxin B of classical biotype in all the isolates. All the isolates except VCH35 harboured an RS1-CTX prophage array on the large chromosome. The isolate VCH35 contained a tandem repeat of classical CTX prophage on the small chromosome. The clonal relationship among the V. cholerae isolates as carried out by enterobacterial repetitive intergenic consensus sequences PCR, BOX PCR and randomly amplified polymorphic DNA, uniformly showed a genetic relationship among the outbreak isolates. The results of this study suggest that altered El Tor biotype V. cholerae with the classical cholera toxin gene are involved in cholera outbreaks in India.
authors.affiliation: Biotechnology Division, Defence Research & Development Establishment, Jhansi Road, Gwalior 474002, India. akgoel73@yahoo.co.uk
authors.forename: Ajay Kumar
authors.initials: AK
authors.lastname: Goel
authors.forename: Meenu
authors.initials: M
authors.lastname: Jain
authors.forename: Pramod
authors.initials: P
authors.lastname: Kumar
authors.forename: Pennagaram
authors.initials: P
authors.lastname: Sarguna
authors.forename: Meera
authors.initials: M
authors.lastname: Bai
authors.forename: Neha
authors.initials: N
authors.lastname: Ghosh
authors.forename: Natrajan
authors.initials: N
authors.lastname: Gopalan
mesh_terms: D015373:Bacterial Typing Techniques; D002771:Cholera / Q000453:epidemiology* / Q000382:microbiology*; D002772:Cholera Toxin / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004196:Disease Outbreaks; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D007194:India / Q000453:epidemiology; D017720:Molecular Epidemiology; D058889:Molecular Typing; D016133:Polymerase Chain Reaction; D039002:Prophages / Q000235:genetics; D041241:Vibrio cholerae O1 / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D004269:DNA, Bacterial; D002772:Cholera Toxin