Pandemic strains of O3:K6 Vibrio parahaemolyticus in the aquatic environment of Bangladesh

M. Sirajul Islam, Rizwana Tasmin, Sirajul Islam Khan, Habibul Bari Mahmud Bakht, Zahid Hayat Mahmood, M. Ziaur Rahman, Nurul Amin Bhuiyan, Mitsuaki Nishibuchi, G. Balakrish Nair, R. Bradley Sack, Anwar Huq, Rita R. Colwell, David A. Sack

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


A total of 1500 environmental strains of Vibrio parahaemolyticus, isolated from the aquatic environment of Bangladesh, were screened for the presence of a major V. parahaemolyticus virulence factor, the thermostable direct haemolysin (tdh) gene, by the colony blot hybridization method using a digoxigenin-labeled tdh gene probe. Of 1500 strains, 5 carried the tdh sequence, which was further confirmed by PCR using primers specific for the tdh gene. Examination by PCR confirmed that the 5 strains were V. parahamolyticus and lacked the thermostable direct haemolysin-related haemolysin (trh) gene, the alternative major virulence gene known to be absent in pandemic strains. All 5 strains gave positive Kanagawa phenomenon reaction with characteristic β-haemolysis on Wagatsuma agar medium. Southern blot analysis of the HindIII-digested chromosomal DNA demonstrated, in all 5 strains, the presence of 2 tdh genes common to strains positive for Kanagawa phenomenon. However, the 5 strains were found to belong to 3 different serotypes (O3:K29, O4:K37, and O3:K6). The 2 with pandemic serotype O3:K6 gave positive results in group-specific PCR and ORF8 PCR assays, characteristics unique to the pandemic clone. Clonal variations among the 5 isolates were analyzed by comparing RAPD and ribotyping patterns. Results showed different patterns for the 3 serotypes, but the pattern was identical among the O3:K6 strains. This is the first report on the isolation of pandemic O3:K6 strains of V. parahaemolyticus from the aquatic environment of Bangladesh.

Original languageEnglish (US)
Pages (from-to)827-834
Number of pages8
JournalCanadian Journal of Microbiology
Issue number10
StatePublished - Oct 2004
Externally publishedYes


  • Aquatic environment
  • Pandemic strains
  • Vibrio parahaemolyticus

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Applied Microbiology and Biotechnology
  • Molecular Biology
  • Genetics


Dive into the research topics of 'Pandemic strains of O3:K6 Vibrio parahaemolyticus in the aquatic environment of Bangladesh'. Together they form a unique fingerprint.

Cite this