A molecular epidemiological study of Vibrio cholerae in Australia.

Two hundred and eight strains of Vibrio cholerae serovar O1 and 454 non-O1 strains, which were isolated within or imported into Australia, were tested for the production of cholera enterotoxin and for hybridization with gene probes for cholera enterotoxin. Genetic relationships among representative isolates were studied by a comparison of the restriction-endonuclease digest patterns of the chromosomal DNA and by Southern-blot analysis of toxigenic strains with the cholera-toxin gene probe. V. cholerae O1 isolates from patients and from the environment were predominantly toxigenic in contrast with the non-O1 isolates. The local O1 isolates were found to be diverse genetically and were unrelated to the imported O1 isolates, to those from other endemic areas and to non-O1 isolates.