Comparison of virulence gene profiles and genomic fingerprints of O1 and non-O1/non-O139 isolates from diarrheal patients in southern Thailand.

BACKGROUND

is associated with severe watery diarrheal disease among people in many parts of the world, including the coastal provinces of Southern Thailand. There are relatively few studies focusing on the genetic characterization among isolates in this region. Therefore, this study aimed at exploring the presence of virulence genes and DNA fingerprints among O1 and nonO1/nonO139 isolates obtained from clinical samples in four southern coastal provinces during the period of 20012009 ( = 21).

RESULTS

All O1 isolates possessed , , , , , and genes. However, only , , and genes were detected in the majority of the nonO1/nonO139 isolates. All O1 isolates showed indistinguishable PCR fingerprints by arbitrarily primed (AP)PCR and enterobacterial repetitive intergenic consensus (ERIC)PCR regardless of the geographical area and period of isolation. However, the multi-locus variable-number of tandem-repeat analysis (MLVA) could differentiate these O1 isolates ( = 11) into eight profiles. Isolates exhibiting an undistinguished MLVA profile also showed identical pulsed-field gel electrophoresis (PFGE). In addition, the O1 isolates were grouped into the same cluster by all methods used in this study.

CONCLUSIONS

This study demonstrated the presence of virulence genes and genetic diversity among different serogroups of isolates from clinical samples in southern Thailand. O1 isolated over a period of multiple years were genetically related, suggesting that they had a clonal origin, whereas nonO1/nonO139 isolates could have evolved independently.