Background: Infrequent restriction site PCR (IRS-PCR) is a recently described DNA fingerprinting technique based on selective amplification of restriction endonuclease-cleaved fragments. We applied of IRS-PCR to clinical isolates of Vibrio parahaemolyticus associated with diarrhea.

Methods: IRS-PCR assay was performed with adaptors for XbaI and HhaI restriction sites. A total of 35 strains of V. parahaemolyticus which were isolated from clinical specimens of patients with diarrhea were analyzed. The isolates were collected from different geographic areas of Seoul (n=12), Incheon (n=21) and Gwangju (n=2) during 1998-2000 in Korea.

Results: In IRS-PCR, amplifed DNA fragments between 50 and 400 bp were found to be the most reproducible in this study. When V. parahaemolyticus isolates were amplified with AH1 and PX-G as primers, 35 isolates could be grouped into five IRS-PCR patterns: A (n=16), B (n=4), C (n=6), D (n=5) and E (n=4). The patterns were subdivided into 15 subtypes: A1, A2, B1, B2, B3, B4, C1, C2, C3, D1, D2, D3, E1, E2 and E3. The IRS-PCR patterns of V. parahaemolyticus did not show any relationship with serotype or geographic origin, but the isolates from same outbreak produced a same pattern(A1).

Conclusion:The results provide evidence of the discriminatory power of the IRS-PCR method as it applies to V. parahaemolyticus. (Korean J Clin Microbiol 2002;5:119-123)