title: Characteristics of Vibrio cholerae O1 isolated from water of the River Ganga, Varanasi, India.
abstract: BACKGROUND
  Vibrio cholerae is an autochthonous inhabitant of fresh and brackish water and estuarine system. Investigation of V. cholerae from the River Ganga seems important to find variation in CTX arrangement and genomic diversity.
  
  
  OBJECTIVE
  To investigate V. cholerae O1 strains for the presence of virulence and regulatory genes, variation in number and organisation of the pre-CTXΦ and/or CTXΦ, and for the genomic diversity.
  
  
  METHODS
  Polymerase chain reaction (PCR) was used to detect virulence and regulatory genes, type of rstR and location of CTXΦ on the chromosome. Southern hybridisation was conducted to see the number and arrangement of pre-CTXΦ and CTXΦ. Ribotyping and pulsed-field gel electrophoresis were used to find genetic relatedness.
  
  
  RESULTS
  Seven strains gave positive results by PCR for the gene encoding for ctx A, zot, ace, tcp A (El Tor), omp U, and tox R, except one strain that was negative for the ctx A. Three strains were positive for the tcp A (El Tor), omp U and tox R genes. Determination of CTX organisation showed that among the ctx-positive strains, four harboured two copies of CTXETΦ arranged in tandem and two harboured one copy of CTXETΦ, and one ctx-negative strain harboured only one copy of pre-CTXETΦ. Pulsotype and ribotype analysis showed existence of at least three pulsotype and ribotypes indicating diversity in genomic content among them.
  
  
  CONCLUSIONS
  This study thus indicates that multiple clones (ribotypes/pulsotypes) of V. cholerae O1 carrying pre-CTXΦ and/or CTXΦ and ctx-negative strains were present in the water of the River Ganga, Varanasi, India.
authors.forename: S S
authors.initials: SS
authors.lastname: Mohaptra
authors.forename: C K
authors.initials: CK
authors.lastname: Mantri
authors.forename: T
authors.initials: T
authors.lastname: Bhotra
authors.affiliation: Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, Odisha, India.
authors.forename: D V
authors.initials: DV
authors.lastname: Singh
mesh_terms: D015139:Blotting, Southern; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005809:Genes, Regulator; D014644:Genetic Variation; D005838:Genotype; D007194:India; D016133:Polymerase Chain Reaction; D039002:Prophages / Q000235:genetics; D021521:Ribotyping; D045483:Rivers / Q000382:microbiology*; D041241:Vibrio cholerae O1 / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D037521:Virulence Factors