Acta Tropica 83 (2002) 169–176 Molecular characterization of Vibrio cholerae O1 outbreak strains in Miri, Sarawak (Malaysia) Son Radu a, *, Micky Vincent a , Kasing Apun b , Raha Abdul Rahim a , Patrick Guda Benjamin c , Yuherman d , Gulam Rusul e a Department of Biotechnology, Faculty of Food Science and Biotechnology, Uniersity Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia b Faculty of Resource Science and Technology, Uniersity Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia c Hospital Miri, 98000 Miri, Sarawak, Malaysia d Department of Animal Science, Kampus Limau Manis, Uniersitas Andalas, Padang, Indonesia e Department of Food Science, Faculty of Food Science and Biotechnology, Uniersity Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Received 20 July 2001; received in revised form 18 March 2002; accepted 15 April 2002 Abstract Bacterial resistance to various antimicrobial agents is common in area with high usage of antibiotics. In this study, the data on antimicrobial susceptibility patterns of Vibrio cholerae O1 from patients during an outbreak period was found to be high but variable rates of multidrug resistance. Thirty-two of 33 V. cholerae isolates harboured the tcp, ctx, zot and ace genes, suggesting their possible roles in the outbreak cases. We analyzed the molecular diversity of a total of 33 strains of V. cholerae O1 isolated from 33 patients between November 1997 and April 1998 using random amplified polymorphic DNA (RAPD) analysis. The 30 typable isolates could be separated into four major clusters containing 5, 17, 2 and 6 isolates, respectively. However, no particular RAPD pattern was predictive of a particular pattern of antibiotic susceptibility. The findings of this study showed that multiple clones seemed to be responsible for cases in the outbreaks in the study area. © 2002 Elsevier Science B.V. All rights reserved. Keywords: Vibrio cholerae O1; Antibiotic resistance; Toxin genes; RAPD-PCR; Malaysia www.parasitology-online.com 1. Introduction Epidemic and endemic cholera is a major public health hazard for many developing countries and continues to be an important cause of morbidity and mortality in many areas of Asia, Africa and Latin America. Vibrio cholerae carrying the type O1 antigen has been regarded as the main causative agent of these epidemics, with the re- maining non-O1 strains considered of less epi- demic importance. However, a new epidemic strain of V. cholerae O139 Bengal emerge in India in late 1992 and spread to neighbouring countries (Albert et al., 1993; Ramamurthy et al., 1993; * Corresponding author. Tel.: +60-3-89486101x8361; fax: +60-3-89423552. E-mail address: son@fsb.upm.edu.my (S. Radu). 0001-706X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved. PII:S0001-706X(02)00110-9