COMPARISON OF PULSED-FIELD GEL-ELECTROPHORESIS AND RIBOTYPING FOR SUBTYPING OF VIBRIO-CHOLERAE O139 ISOLATED IN THAILAND

Pulsed-field gel electrophoresis (PFGE) of Cpo I-digested genomic DNA and ribotyping (Bgl I) were applied to 60 Vibrio cholerae strains incl uding 48 V. cholerae O139 from Thailand to compare their value in diff erentiating strains of the present V. cholerae O139 epidemic. PFGE pat terns were divided into groups A and B representing five and four subt ypes, respectively, while ribotyping showed four different patterns. P FGE group B subtypes were only presented among O139 isolates from Thai land, whereas four O139 strains from Bangladesh and India showed ident ical PFGE group A subtypes observed in O139 isolates from Thailand. Tw o nontoxigenic O139 isolates from Thailand showed different and unique PFGE types as did five V. cholerae non-O1 non-O139 isolates containin g a gene virulence complex found in V. cholerae O139. These results in dicate that PFGE (Cpo I) can resolve recent evolutionary divergence wi thin V. cholerae O139 and offers a useful supplementary tool for follo wing the progressing V. cholerae O139 epidemic.