Different Yersinia enterocolitica 4:O3 genotypes found in pig tonsils in Southern Germany and Finland.

Summary The distribution of different genotypes of Y. enterocolitica 4:O3 strains recovered from pig tonsils in Southern Germany and Finland in 1999–2000 was investigated. A total of 96 and 207 Y. enterococolitica 4:O3 isolates recovered from 47 and 66 tonsils of finishing pigs in Germany and Finland, respectively, were characterised with PFGE using Not I enzyme. In all, 39 different Not I profiles were obtained, only one of which, NB1, was found in both Germany and Finland. All strains were further characterised with Apa I and Xho I enzymes. When the 54 German and 74 Finnish strains were characterised with all three enzymes, 51 genotypes were obtained. The 23 genotypes found in German strains differed from the 28 found in Finnish strains. These results indicate that Y. enterocolitica 4:O3 genotypes have a differential geographical distribution and thus can be used in epidemiological studies.