Comparison of Salmonella enterica serovar Abortusequi isolates of equine origin by pulsed-field gel electrophoresis and fluorescent amplified-fragment length polymorphism fingerprinting

Abstract Equine paratyphoid is caused by Salmonella enterica serovar Abortusequi, and manifests mainly as abortion in the mare. We compared S . Abortusequi strains isolated in Japan and other countries using pulsed-field gel electrophoresis (PFGE) and fluorescent amplified-fragment length polymorphism (FAFLP) analysis. PFGE analysis of S . Abortusequi strains gave 21–27 fragments ranging in size from 33 to 602 kb. Although two PFGE profiles were observed among the 20 S . Abortusequi isolates in Japan, the restriction fragments originating from the chromosome were common between the two profiles. The similarity index of the two profiles was 90.9%, while those between Japanese and five other S . Abortusequi strains were 29.8–37.5%. On the other hand, FAFLP analysis of S . Abortusequi strains generated 64–67 amplified fragments ranging in size from 100 to 400 bp. One polymorphic fragment was observed among the 20 S . Abortusequi isolates in Japan. These data indicate the close relation of this agent in Japan. S . Abortusequi strains sharing a common ancestry might have been conserved in Japan.