OBJECTIVETo investigate the epidemiological and molecular typing features of the pathogenic Yersinia enterocolitica strains isolated in China,using pulsed field gel electrophoresis(PFGE) and standardized PFGE method as well as typing database of Yersinia enterocolitica.

METHODSPFGE analysis was performed as Laboratory Directions for molecular subtyping of Salmonella by PFGE (PulseNet,USA) with some modifications and the results of PFGE were analyzed by BioNumerics soft (Version 4.0, Applied Maths BVBA, Belium).

RESULTS114 O:3 Yersinia enterocolitica strains were typed by 25 patterns to have found that K6GN11C30012 (50 strains), K6GN11C30015(19 strains) and K6GN11C30016(10 strains) were the major patterns. K6GNllC30012 had 92.2% cluster similarity with K6GN11C30009-K6GN11C30023. This clone included 91.23% strains of 114 0:3 Yersinia enterocolitica strains. 51 0:9 Yersinia enterocolitica strains were typed by 14 patterns; K6GN11C90004 (22 strains) and K6GN11C90010 (13 strains)were the major patterns. K6GN11C90004 had 81.8% cluster similarity with K6GN11C90010 patterns. The major patterns of 0:3 and 0:9 serotypes were quite different.

CONCLUSIONO:3 Yersinia enterocolitica strains might originate from the same clone and had very few variation in different years and provinces but O:9 Yersinia enterocolitica strains from two different clones with some changes.