DIFFERENTIATION OF CAMPYLOBACTER-JEJUNI AND CAMPYLOBACTER-COLI STRAINS BY USING RESTRICTION-ENDONUCLEASE DNA PROFILES AND DNA FRAGMENT POLYMORPHISMS

The chromosomal DNA fragment patterns from a total of 169 Campylobacte r jejuni and Campylobacter coli isolates from poultry and humans were analyzed by using DNA restriction endonucleases ClaI and EcoRV. The DN A restriction patterns produced by ClaI and EcoRV consisted of unique DNA fragments of 9 to 9.5 kb and 3.5 kb generated,vith ClaI and a sing le unique fragment of 3.0 kb produced by EcoRV. These patterns were ob tained with all strains of C.jejuni tested. The DNA restriction patter ns were further examined by Southern blot analysis with a previously c onstructed DNA probe, pMO2005, which is also able to distinguish betwe en C. jejuni and C. coli spp. (5). Two types of patterns were produced by hybridization with the ClaI-cleaved DNA of C. jejuni strains, one of a single 18.5-kb genomic fragment and the other of 14.5- and 4.0-kb fragments. This indicated the presence of an extra ClaI site in this genomic fragment in the strains with the duplex pattern. The Southern blot analysis of 169 C. jejuni and C. coli isolates from poultry and f rom humans with DNA probe pMO2005 demonstrated that 78% of C. jejuni s trains isolated from chickens hybridized with DNA probe pMO2005 with a characteristic 14.5- and 4.0-kb banding pattern and 22% hybridized wi th a single 18.5-kb fragment, whereas 71% of human isolates hybridized with the single 18.5-kb fragment and only 29% hybridized with 14.5- a nd 4.0-kb fragments. These findings suggest that only a small proporti on of C. jejuni strains that colonize chickens may cause disease in hu mans.