Dissemination of a single Vibrio cholerae clone in cholera outbreaks during 2005 in Iran

Abstract

In this study, 50 Vibrio cholerae O1 serotype Inaba isolates were collected during several cholera outbreaks throughout Iran during the summer of 2005. The results of antibiotic susceptibility testing showed that 86, 84, 84 and 82 % of the isolates were resistant to streptomycin, chloramphenicol, co-trimoxazole and tetracycline, respectively. The strains were genotyped using randomly amplified polymorphic DNA (RAPD), PFGE and ribotyping techniques. PCR showed that 100, 98 and 98 % carried the ctx, zot and ace genes, respectively. Biochemical fingerprinting of the isolates using the PhenePlate (PhP) system showed a low diversity index level (0.755), suggesting that the strains were highly homogeneous. Among the strains, 100 and 96 % showed an identical ribotype and PFGE patterns, respectively. The two isolates showing different PFGE patterns also exhibited discrete PhP types. RAPD was able to discriminate the isolates into six distinct groups, suggesting some genetic dissimilarity was present among the strains. These ribotyping, PFGE and PhP techniques revealed the clonal dissemination of a single V. cholerae strain throughout Iran in 2005.