CLONAL DIVERSITY OF VIBRIO-CHOLERAE 01 EVIDENCED BY RIBOSOMAL-RNA GENE RESTRICTION PATTERNS

The rRNA gene restriction patterns of 89 Vibrio cholerae 01 isolates from different geographic origins were studied. The probe was Escherichia coli 16 + 23 S rRNA labelled with "ECL Gene detection systesm". A total of 17 rRNA gene restriction patterns were observed after BglI cleavage. Four patterns (B1 to B4) were only given by biotype cholerae (14 strains studied). Thirteen patterns (B5 to B17) were only given by biotype El Tor (75 strains studied). There was no correlatin between serotypes and rRNA gene restriction patterns. This study provides arguments that (1) strains of biotypes cholerae and EL Tor are different clones, (2) a cholera pandemic is not a single world-wide epidemic (due to a single clone) but rather a simultaneous occurrence of several epidemics (several clones involved), and (3) epidemic waves of biotype El Tor could be due to the emergence of new clones. © 1990.