Cryptic Appearance of a New Clone of Vibrio cholerae Serogroup O1 Biotype El Tor in Calcutta, India

• Published in: MICROBIOLOGY and IMMUNOLOGY 1997, Vol.41(1), pp.1-6
• Main Authors: Yamasaki, Shinji, Nair, G. Balakrish, Bhattacharya, S.K., Yamamoto, Shingo, Kurazono, Hisao, Takeda, Yoshifumi
• Format: Article
• Language: English
• Subjects: Bacteriology; Biological and medical sciences; Epidemiology; Fundamental and applied biological sciences. Psychology; Genomic analysis; Microbiology; New clone; Pulsed-field gel electrophoresis; Vibrio cholerae; Vibrio cholerae O1 biotype El Tor
• ISSN: 0385-5600; 1348-0421
• DOI: 10.1111/j.1348-0421.1997.tb01165.x

In this study, pulsed-field gel electrophoresis (PFGE) was applied to determine if the Vibrio cholerae O1 strains which reappeared after being temporarily displaced in Calcutta by the O139 serogroup were different from those isolated before the advent of the O139 serogroup. NotI digestion generated a total of 11 different patterns among the 24 strains of V. cholerae randomly selected to represent different time frames. Among the V. cholerae O1 strains isolated after July 1993, 4 PFGE banding patterns designated as H through K were observed with pattern H dominating. Pattern H was distinctly different from all other patterns encountered in this study including patterns A, B and C of V. cholerae O1 El Tor, which dominated before November 1992, and pattern F, which was the dominant V. cholerae O139 pattern. Further, pattern H was also different from the NotI banding patterns of the representative strains of the 4 toxigenic clonal groups of V. cholerae O1 El Tor currently prevailing in different parts of the world. NotI fragments of the new clone of V. cholerae O1 did not hybridize with an O139 specific DNA probe, indicating that there was no O139 genetic material in the new clone of V. cholerae O1. Hybridization data with an O1-specific DNA probe again differentiated between the clones of V. cholerae O1 existing before the genesis of the O139 serogroup and the O1 strains currently prevalent.