EN
The paper presents a study of the prevalence of suilysin, MRP and EF protein encoding genes - considered to be important virulence factors in Streptococcus suis. Of the 63 strains included in the study, 44 were isolated from the tissues of streptococcosis affected pigs and 19 from the tonsils of healthy carrier animals. The suilysin gene was detected in 79% of the strains; mrp and ef genes were detected in 54% and 51% respectively; and the ef* gene was present in 4 strains. Genotypes of the isolated strains were also analyzed. The majority of the strains (35%), isolated from both diseased as well as healthy pigs represented genotype sly+ mrp+ ef+ but in 6 strains (10%), (five of which were isolated from diseased pigs) none of the genes were detected. The study concluded that the capacity of Streptococcus suis to produce suilysin and other virulent proteins may have a direct impact on the pathological potential of Streptococcus suis strains.