Abstract
Two hundred and four strains of S. zooepidemicus were isolated from the genital sites of mares diagnosed with metritis. The isolates were differentiated by PCR-RFLP analysis of the szp gene. The 30 kinds of restriction fragment profiles were defined by 4 to 6 sizes of DNA fragments ranging from approximately 65 to 390 bp. Although 16 of the 30 PCR-RFLP profiles consisted of 149 isolates, 73% were identical to the szp of the organisms from horses with respiratory disease. The remaining 14 consisted of 55 isolates of which 27% were newly found. Ten genital swabs which were positive for isolation of the organisms were used to investigate whether the 5 clones of the organisms from a single sample were genetically identical to each other or not. Results showed each of 5 clones to be indistinguishable, expect for 1 clone from a single swab. In conclusion, the usefulness of PCR-RFLP analysis in discriminating between strains was demonstrated on genital isolates in the same way as for respiratory isolates, suggesting that the major isolates were szp genotypes that are present at both genital and respiratory sites, even though it was suspected that some genotypes specifically infect the genital site or the respiratory site.
