| 2008 |
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| Molecular typing of Vibrio cholerae O1 isolates from Thailand by pulsed-field gel
electrophoresis. |
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| Tapchaisri, P., Na-Ubol, M., Tiyasuttipan, W., Chaiyaroj, S. C., Yamasaki, S., Wongsaroj, T.,
Hayashi, H., Nair, G. B., Chongsa-Nguan, M., Kurazono, H., and Chaicumpa, W. |
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| Faculty of Allied Health Sciences, Thammasat University, Rangsit Center, Pathum-thani, Thailand
alpts@diamondmahidolacth |
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| Abstract: The aim of the present study was to genotypically characterize Vibrio cholerae strains
isolated from cholera patients in various provinces of Thailand. Two hundred and forty V. cholerae O1 strains, isolated from patients with cholera during
two outbreaks, i.e. March 1999-April 2000 and December 2001-February 2002, in Thailand, were genotypically characterized by NotI digestion and pulsed
-field gel electrophoresis (PFGE). In total, 17 PFGE banding patterns were found and grouped into four Dice-coefficient clusters (PF-I to PF-IV). The
patterns of V. cholerae O1, El Tor reference strains from Australia, Peru, Romania, and the United States were different from the patterns of reference
isolates from Asian countries, such as Bangladesh, India, and Thailand, indicating a close genetic relationship or clonal origin of the isolates in the same
geographical region. The Asian reference strains, regardless of their biotypes and serogroups (classical O1, El Tor O1, O139, or O151), showed a
genetic resemblance, but had different patterns from the strains collected during the two outbreaks in Thailand. Of 200 Ogawa strains collected during the
first outbreak in Thailand, two patterns (clones)--PF-I and PF-II--predominated, while other isolates caused sporadic cases and were grouped together as
pattern PF-III. PF-II also predominated during the second outbreak, but none of the 40 isolates (39 Inaba and 1 Ogawa) of the second outbreak had the
pattern PF-I; a minority showed a new pattern--PF-IV, and others caused single cases, but were not groupable. In summary, this study documented the
sustained appearance of the pathogenic V. cholerae O1 clone PF-II, the disappearance of clones PF-I and PF-III, and the emergence of new pathogenic
clones during the two outbreaks of cholera. Data of the study on molecular characteristics of indigenous V. cholerae clinical isolates have public-health
implications, not only for epidemic tracing of existing strains but also for the recognition of strains with new genotypes that may emerge in the
future |
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| Published in:J.Health Popul.Nutr. 26[1], 79-87. 2008. |
