Genotypic diversity and pathogenic potential of Yersinia enterocolitica biotype 2 strains isolated in Brazil.

AIMS: To investigate the pathogenic potential and genotypic diversity of Yersinia enterocolitica biotype 2 strains isolated in Brazil and to compare these strains with other Y. enterocolitica biotypes using ERIC-PCR and PFGE.

METHODS AND RESULTS: Forty strains of Y. enterocolitica biotype 2 (B2) isolated from humans (5), the environment (34) and animal (1), in Brazil over 19 years were studied. In addition to these isolates, we also analysed 26 Y. enterocolitica strains belonging to the biotypes 1A, 1B, and 3-5. All of the B2 strains contained the genes inv, ail, ystA, hreP, tccC and myfA. The genes fepD and fes were detected in 39 (97·5%) strains, virF was found in three (7·5%) strains, and ystB and fepA were not detected in any strains. The B2 strains showed genotypic similarities of more than 84·8% by ERIC-PCR and of more than 69·0% by PFGE.

CONCLUSIONS: The pathogenic potential of the B2 strains examined in this study was highlighted by the occurrence of the majority of the virulence markers searched. The results of the ERIC-PCR and PFGE showed that the B2 strains evaluated in this study had a high genotypic similarity, suggesting that these strains differed little over the 19 year study period and that the environment was a possible source of contamination of humans and animals in Brazil. Furthermore, the ERIC-PCR technique grouped the strains belonging to Y. enterocolitica biotypes 1A, 1B, 2, 3, 4 and 5 according to their pathogenicity.

SIGNIFICANCE AND IMPACT OF THE STUDY: This study provided new information about the pathogenic potential and genotypic similarity of Y. enterocolitica B2 isolated from diverse sources in Brazil. Furthermore, ERIC-PCR showed to be a valuable tool for grouping Y. enterocolitica of different biotypes according their pathogenicity.