title: Vibriophage VcA-3 as an epidemic strain marker for the U.S. Gulf Coast Vibrio cholerae O1 clone.
abstract: Toxigenic and nontoxigenic Vibrio cholerae O1, El Tor biotype strains, which are endemic to the U.S. Gulf Coast, can be lysogenic for bacteriophage VcA-3. To evaluate the presence of VcA-3 as an indicator of toxigenicity and as an epidemic strain marker, phage production and the presence of phage and cholera toxin genes were assayed in 98 strains of V. cholerae O1 (35 U.S. and 63 foreign strains). By using a HindIII chromosomal digest for Southern blot analysis, 39 of the study strains hybridized with the VcA-3 probe in 10 banding patterns. The 15 toxigenic and 6 of the 20 nontoxigenic U.S. isolates gave four VcA-3-related patterns. Among the foreign isolates, 12 of 12 toxigenic classical biotype strains, 1 of 43 toxigenic El Tor biotype strains, and 3 of 8 nontoxigenic atypical strains gave six patterns that were clearly distinct from that of VcA-3. Compared with Southern blot analysis, the phage production assay had a sensitivity of 1.0 and a specificity of 0.48, while the colony hybridization assay had a sensitivity of 1.0 and a specificity of 0.77 for identification of VcA-3. Neither assay reliably identified the toxigenic Gulf Coast clone. The presence of VcA-3, as defined by Southern blot analysis, always separated toxigenic U.S. from foreign isolates and often from nontoxigenic U.S. isolates of V. cholerae O1.
authors.affiliation: Department of Parasitology, School of Public Health, University of North Carolina, Chapel Hill 27514.
authors.forename: R J
authors.initials: RJ
authors.lastname: Almeida
authors.forename: D N
authors.initials: DN
authors.lastname: Cameron
authors.forename: W L
authors.initials: WL
authors.lastname: Cook
authors.forename: I K
authors.initials: IK
authors.lastname: Wachsmuth
mesh_terms: D015373:Bacterial Typing Techniques; D001435:Bacteriophages / Q000235:genetics / Q000302:isolation & purification*; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology; D002772:Cholera Toxin / Q000235:genetics / Q000302:isolation & purification; D015342:DNA Probes; D004269:DNA, Bacterial / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D004196:Disease Outbreaks; D006801:Humans; D009693:Nucleic Acid Hybridization; D014481:United States / Q000453:epidemiology; D014734:Vibrio cholerae / Q000145:classification* / Q000235:genetics / Q000472:pathogenicity
chemical_list: D015342:DNA Probes; D004269:DNA, Bacterial; D004279:DNA, Viral; D002772:Cholera Toxin