Phage Type 187 as a Separate Subunit MboI Restriction Site Within the Staphylococcus aureus Species

The aim of this study was to use MboI restriction of pta gene fragment to compare the strains of Staphylococcus aureus phage type 187 and other phage types of S. aureus isolated from humans and dogs, as well as canine S. intermedius group strains. The study included 395 human and canine staphylococcal strains representing S. aureus, S. intermedius, and S. pseudintermedius species. The strains were identified with classic phenotypic methods and by the presence of species-specific thermostable nuclease (nuc SA) gene. All the strains were subjected to the analysis of MboI restriction site of pta gene fragment with PCR–RFLP method. Nearly, all human and animal strains of S. aureus possessed 156- and 164-bp restriction fragments. One of the human strains lacked the 320-bp amplification product. In the case of all S. aureus phage type 187, the amplification product of pta gene was insusceptible to cutting with MboI restrictase. None of S. intermedius strains possessed restriction sites present in the product of amplification of pta gene, while all the strains of S. pseudintermedius had 213- and 107-bp restriction fragments. In conclusion, our findings regarding S. aureus phage type 187 reveal that within the population of strains of S. aureus species, these bacteria represent a group with distinct properties.