Volume 6, Number 2—April 2000
Research
Vibrio cholerae O139 in Calcutta, 1992-1998: Incidence, Antibiograms, and Genotypes
Figure 1

Figure 1. Monthly isolation profile of the Vibrio cholerae O1 and O139 serogroups from patients hospitalized with acute secretory diarrhea at the Infectious Diseases Hospital, Calcutta, India, from March 1992 to December 1998. Arrows denote the month in which changes in V. cholerae strains were noted: A, appearance of V. cholerae O139 in Calcutta in November 1992; B, displacement of V. cholerae O1 by V. cholerae O139 in January 1993; C, reappearance of V. cholerae O1; D, domination of V. cholerae O1 over V. cholerae O139; E, isolation of nontoxigenic V. cholerae O139 in April 1995; F, appearance for the first time of cotrimoxazole-susceptible strains of V. cholerae O139; G, appearance of cotrimoxazole-susceptible and neomycin-resistant strains of V. cholerae O139; H, domination of V. cholerae O139 over V. cholerae O1; I, replacement of V. cholerae O139 by V. cholerae O1 as the major cholera causing serogroup; J, appearance of cotrimoxazole- and streptomycin-susceptible strains of V. cholerae O139.