A molecular surveillance reveals the prevalence of Vibrio cholerae O139 isolates in China from 1993 to 2012

• Published in: Journal of clinical microbiology 2014-04, Vol.52 (4), p.1146-1152
• Main Authors: Zhang, Ping, Zhou, Haijian, Diao, Baowei, Li, Fengjuan, Du, Pengcheng, Li, Jie, Kan, Biao, Morris, Jr, J Glenn, Wang, Duochun
• Format: Article
• Language: English
• Subjects: Bacteriology; China - epidemiology; Cholera - epidemiology; Cholera - microbiology; Cholera Toxin - genetics; Cholera Toxin - secretion; Cluster Analysis; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; Electrophoresis, Gel, Pulsed-Field; Environmental Microbiology; Epidemiological Monitoring; Genes, Bacterial; Genotype; Humans; Molecular Epidemiology; Molecular Sequence Data; Multilocus Sequence Typing; Prevalence; Prophages - genetics; Vibrio cholerae; Vibrio cholerae O139 - classification; Vibrio cholerae O139 - genetics; Vibrio cholerae O139 - isolation & purification; Vibrio cholerae O139 - pathogenicity
• ISSN: 0095-1137; 1098-660X
• DOI: 10.1128/JCM.03354-13

Vibrio cholerae serogroup O139 was first identified in 1992 in India and Bangladesh, in association with major epidemics of cholera in both countries; cases were noted shortly thereafter in China. We characterized 211 V. cholerae O139 isolates that were isolated at multiple sites in China between 1993 and 2012 from patients (n = 92) and the environment (n = 119). Among clinical isolates, 88 (95.7%) of 92 were toxigenic, compared with 47 (39.5%) of 119 environmental isolates. Toxigenic isolates carried the El Tor CTX prophage and toxin-coregulated pilus A gene (tcpA), as well as the Vibrio seventh pandemic island I (VSP-I) and VSP-II. Among a subset of 42 toxigenic isolates screened by multilocus sequence typing (MLST), all were in the same sequence type as a clinical isolate (MO45) from the original Indian outbreak. Nontoxigenic isolates, in contrast, generally lacked VSP-I and -II, and fell within 13 additional sequence types in two clonal complexes distinct from the toxigenic isolates. In further pulsed-field gel electrophoresis (PFGE) (with NotI digestion) studies, toxigenic isolates formed 60 pulsotypes clustered in one group, while the nontoxigenic isolates formed 43 pulsotypes which clustered into 3 different groups. Our data suggest that toxigenic O139 isolates from widely divergent geographic locations, while showing some diversity, have maintained a relatively tight clonal structure across a 20-year time span. Nontoxigenic isolates, in contrast, exhibited greater diversity, with multiple clonal lineages, than did their toxigenic counterparts.