GENETIC-ANALYSIS OF EQUINE METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS BY PULSED-FIELD GEL-ELECTROPHORESIS

Pulsed-field gel electrophoresis (PFGE) was used:to determine genetic relationships among 15 methicillin-resistant Staphylococcus aureus (MR SA) isolates from mares with metritis and from a stallion with dermati tis in Hokkaido. All the 15 isolates showed phage pattern 6/47/54/75, coagulase type IV, and enterotoxin type A. The restriction endonucleas e SmaI cut their genomic DNAs into 15 or 16 fragments ranging in size from 8 to 630 kb. Fourteen of the 15 isolates showed the same PFGE pat tern, whereas the remaining one appeared to be closely related. The 9 human MRSA isolates showing the same phenotypic characteristics as the horse isolates gave different PFGE patterns from those of the horse i solates.