title: Vibrio cholerae classical biotype strains reveal distinct signatures in Mexico.
abstract: Vibrio cholerae O1 classical (CL) biotype caused the fifth and sixth pandemics, and probably the earlier cholera pandemics, before the El Tor (ET) biotype initiated the seventh pandemic in Asia in the 1970s by completely displacing the CL biotype. Although the CL biotype was thought to be extinct in Asia and although it had never been reported from Latin America, V. cholerae CL and ET biotypes, including a hybrid ET, were found associated with areas of cholera endemicity in Mexico between 1991 and 1997. In this study, CL biotype strains isolated from areas of cholera endemicity in Mexico between 1983 and 1997 were characterized in terms of major phenotypic and genetic traits and compared with CL biotype strains isolated in Bangladesh between 1962 and 1989. According to sero- and biotyping data, all V. cholerae strains tested had the major phenotypic and genotypic characteristics specific for the CL biotype. Antibiograms revealed the majority of the Bangladeshi strains to be resistant to trimethoprim-sulfamethoxazole, furazolidone, ampicillin, and gentamicin, while the Mexican strains were sensitive to all of these drugs, as well as to ciprofloxacin, erythromycin, and tetracycline. Pulsed-field gel electrophoresis (PFGE) of NotI-digested genomic DNA revealed characteristic banding patterns for all of the CL biotype strains although the Mexican strains differed from the Bangladeshi strains in 1 to 2 DNA bands. The difference was subtle but consistent, as confirmed by the subclustering patterns in the PFGE-based dendrogram, and can serve as a regional signature, suggesting the pre-1991 existence and evolution of the CL biotype strains in the Americas, independent from Asia.
authors.affiliation: International Center for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh.
authors.forename: Munirul
authors.initials: M
authors.lastname: Alam
authors.forename: M Tarequl
authors.initials: MT
authors.lastname: Islam
authors.forename: Shah Manzur
authors.initials: SM
authors.lastname: Rashed
authors.forename: Fatema-tuz
authors.initials: FT
authors.lastname: Johura
authors.forename: Nurul A
authors.initials: NA
authors.lastname: Bhuiyan
authors.forename: Gabriela
authors.initials: G
authors.lastname: Delgado
authors.forename: Rosario
authors.initials: R
authors.lastname: Morales
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Mendez
authors.forename: Armando
authors.initials: A
authors.lastname: Navarro
authors.forename: Haruo
authors.initials: H
authors.lastname: Watanabe
authors.forename: Nur-A
authors.initials: NA
authors.lastname: Hasan
authors.forename: Rita R
authors.initials: RR
authors.lastname: Colwell
authors.forename: Alejandro
authors.initials: A
authors.lastname: Cravioto
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology*; D016000:Cluster Analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D019353:Endemic Diseases; D006801:Humans; D008800:Mexico / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D012703:Serotyping; D014734:Vibrio cholerae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents