title: Molecular epidemiology of Vibrio cholerae O1 in northern Vietnam (2007-2009), using multilocus variable-number tandem repeat analysis.
abstract: Cholera is an infectious disease of major concern in Vietnam and other Asian countries. In 2009, there was a large outbreak of cholera in northern Vietnam. To investigate relationships among isolates of the causative pathogen Vibrio cholerae in this region since 2007, we carried out a multilocus variable-number tandem repeat analysis (MLVA) of 170 isolates collected between 2007 and 2009. A total of 24 MLVA types were identified using seven loci. Five clones (1-5) were identified using five loci of the large V. cholerae chromosome; clones 1 and 2 were major, and the others were minor. Clone 1 isolates were responsible for the 2009 outbreak. A shift in the predominant clone occurred between 2007 and 2009, with clone 1 likely derived from clone 2. Moreover, the former was less diverse than the latter, suggesting a single source of cholera dissemination. Epidemiological data indicated a wavelet prior to the large outbreak, suggesting that drinking water source or food chain became contaminated during dissemination. Our results reveal the utility of MLVA for analysis of V. cholerae isolates within a relatively short period and broaden our understanding of its transmission and response to cholera.
authors.affiliation: Department of Bacteriology, National Institute for Hygiene and Epidemiology, Hanoi, Vietnam.
authors.forename: Dong Tu
authors.initials: DT
authors.lastname: Nguyen
authors.affiliation: Department of Bacteriology, National Institute for Hygiene and Epidemiology, Hanoi, Vietnam.
authors.forename: Tuan Cuong
authors.initials: TC
authors.lastname: Ngo
authors.affiliation: Department of Bacteriology, National Institute for Hygiene and Epidemiology, Hanoi, Vietnam.
authors.forename: Thanh Huong
authors.initials: TH
authors.lastname: Le
authors.affiliation: Department of Bacteriology, National Institute for Hygiene and Epidemiology, Hanoi, Vietnam.
authors.forename: Hoai Thu
authors.initials: HT
authors.lastname: Nguyen
authors.affiliation: Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.
authors.forename: Masatomo
authors.initials: M
authors.lastname: Morita
authors.affiliation: Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Arakawa
authors.affiliation: Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohnishi
authors.affiliation: Department of Bacteriology, National Institute for Hygiene and Epidemiology, Hanoi, Vietnam.
authors.forename: Binh Minh
authors.initials: BM
authors.lastname: Nguyen
authors.affiliation: Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.
authors.forename: Hidemasa
authors.initials: H
authors.lastname: Izumiya
mesh_terms: D000818:Animals; D002771:Cholera / Q000453:epidemiology* / Q000382:microbiology*; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D018598:Minisatellite Repeats; D017720:Molecular Epidemiology; D058889:Molecular Typing; D041241:Vibrio cholerae O1 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D014744:Vietnam / Q000453:epidemiology