EN
The aim of the study was to compare genetic profiles of selected bacterial groups isolated from nasal mucosa of horses with upper respiratory tract infections. The RAPD method with the use of a commercial test (Ready-To-Go RAPD Analysis Kit, Amersham Pharmacia Biotech, USA) was used in the study. The representative group of bacterial strains isolated from different horse farms in our earlier studies was subjected to the analysis of the genetic polymorphism. At the preliminary stage all isolates were phenotypically characterized. In total 26 strains of Staphylococcus xylosus, 25 strains of Staphylococcus sciuri, 7 strains of Staphylococcus lentus and 15 strains of Bordetella bronchiseptica were examined. The biggest genetic differentiation was shown within the strains of the St. lentus species, in which 4 different RAPD patterns within 7 strains examined were found (57.1%). In other bacterial species polymorphism of 40%, 53.8% and 26.7% was found in the case of St. sciuri, St. xylosus and B. bronchiseptica respectively. The results showed prominent genetic differentiation within coagulase-negative staphylococci isolated from horses, mainly in St. xylosus species. They also presented different biochemical properties. In contrast, B. bronchiseptica strains constituted a relatively uniform bacterial group both from the genetic perspective as well as based on their phenotypic properties.