Molecular characterization of Vibrio cholerae O1 El Tor strains in Malaysia revealed genetically diverse variant lineages

Thong, Kwai Lin and Tham, Kathryn Bee Lin and Ngoi, Soo Tein and Tan, Shiang Chiet and Yussof, Wan Noraini Wan and Hanapi, Rahayu Ahmad and Mohamad, Nurizzat and Teh, Cindy Shuan Ju (2022) Molecular characterization of Vibrio cholerae O1 El Tor strains in Malaysia revealed genetically diverse variant lineages. Transboundary And Emerging Diseases, 69 (4). E693-E703. ISSN 1865-1674, DOI

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Vibrio cholerae O1 El Tor variants have been the major causative agents of cholera worldwide since their emergence in the 2000s. Cholera remains endemic in some regions in Malaysia. Therefore, we aimed to investigate the genetic characteristics of the V. cholerae O1 El Tor strains associated with outbreaks and sporadic cases to elucidate the molecular evolution among the strains circulating in this region. A total of 45 V. cholerae O1 El Tor strains isolated between 1991 and 2011 were examined. All strains were subjected to phenotypic characterization, and molecular characterization including detection of virulence genes and CTX prophage (CTX phi) by Polymerase Chain Reaction (PCR) and genotyping by Pulsed-Field Gel Electrophoresis (PFGE). All strains were phenotypically confirmed as El Tor biotype and were mostly Ogawa serotype (96%). Antimicrobial susceptibility testing showed that the outbreak strains isolated in 1991 (Sabah) and 2009 (Terengganu) were all multidrug-resistant while the sporadic strains were resistant to erythromycin and furazolidone only. All strains (n = 45) were resistant to erythromycin. The virulence genes ctxA, ctxB, ompW, rfb, rtxC, tcpA, tcpI, rstR, zot and hlyA were present in all strains. The outbreak strains isolated in 1991 harboured El Tor cholera toxin gene (ctxB3) while sporadic strains from 2004 to 2011 harboured classical ctxB1. Four distinctive CTX phi arrays were identified among the El Tor variants, one of which co-occurred with El Tor strains during the 2009 outbreak in Terengganu. PFGE analysis revealed that a genetically diverse El Tor variants population persisted in Sabah. The co-existence of multiple El Tor variants together with the prototypic El Tor strains suggested a multiclonal emergence of V. cholerae O1 El Tor variants in this region.

Item Type: Article
Funders: Universiti Malaya, Universiti Malaya High Impact Research Grant UM.C/625/1/HIR/MOHE/02, Ministry of Science, Technology and Innovation Grant GA03-2013
Uncontrolled Keywords: Cholera toxin; Classical; El Tor variant; Erythromycin; Genotype; Prophage
Subjects: Q Science > QR Microbiology
R Medicine > RA Public aspects of medicine
Divisions: Faculty of Medicine
Faculty of Medicine > Anaesthesiology Department
Deputy Vice Chancellor (Research & Innovation) Office > Nanotechnology & Catalysis Research Centre
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 14 Oct 2023 05:03
Last Modified: 14 Oct 2023 05:03

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