title: Studies on the genesis of Vibrio cholerae O139: identification of probable progenitor strains.
abstract: Four lines of evidence suggest that the recent outbreak strains of Vibrio cholerae O139 could have emerged from serogroup O1 strains typified by isolates M01 and M0477 described in this paper, which are neither truly classical nor truly E1 Tor in their biotype attributes. Firstly, like all O139 isolates, these O1 strains, isolated in Madras during and before the O139 outbreak, were resistant not only to polymyxin B but also to all biotype-specific choleraphages, i.e. classical phage phi 149 and E1 Tor phages e4 and e5. Secondly, the restriction fragment pattern (RFP) polymorphism displayed by these strains for the cholera toxin (ctx) gene, were identical with those produced by O139 isolates but were different from those of O1 type strains, namely V. cholerae 569B (classical) and V. cholerae MAK757 (E1 Tor). Thirdly, all the O139 isolates and the two O1 isolates carried an identical large number of copies of cholera toxin gene in their chromosomes. Finally, the outer-membrane protein profiles of strains M01 and M0477 were identical to those of O139 isolates but were different from those displayed by strains 569B and MAK757.
authors.affiliation: Institute of Microbial Technology, Chandigarh, India.
authors.forename: S
authors.initials: S
authors.lastname: Pajni
authors.forename: C
authors.initials: C
authors.lastname: Sharma
authors.forename: N
authors.initials: N
authors.lastname: Bhasin
authors.forename: A
authors.initials: A
authors.lastname: Ghosh
authors.forename: T
authors.initials: T
authors.lastname: Ramamurthy
authors.forename: G B
authors.initials: GB
authors.lastname: Nair
authors.forename: S
authors.initials: S
authors.lastname: Ramajayam
authors.forename: B
authors.initials: B
authors.lastname: Das
authors.forename: S
authors.initials: S
authors.lastname: Kar
authors.forename: S
authors.initials: S
authors.lastname: Roychowdhury
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000032:analysis; D001435:Bacteriophages; D001459:Bangladesh / Q000453:epidemiology; D015139:Blotting, Southern; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology*; D002772:Cholera Toxin / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis; D004196:Disease Outbreaks; D004591:Electrophoresis, Polyacrylamide Gel; D005798:Genes, Bacterial; D006801:Humans; D007194:India / Q000453:epidemiology; D012150:Polymorphism, Restriction Fragment Length; D011112:Polymyxin B / Q000494:pharmacology; D012703:Serotyping; D014734:Vibrio cholerae / Q000145:classification* / Q000187:drug effects / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D002772:Cholera Toxin; D011112:Polymyxin B