ABSTRACT
Streptococcus suis is one of the most important bacterial pathogens of swine all over the world. Studies on the characterization of this agent in South America are scarce. The present study analyzed 133 isolates of S. suis recovered from affected pigs from different regions of Brazil. These isolates were classified as serotype 2 and further studied for the presence of genes codifying EF, MRP and suilysin. Results obtained showed the occurrence of eight genotypes, represented by different combinations of these virulence factors. The genotype EF+, MRP+ and suylisin+ was the most frequent, followed by (EF*, MRP+, suilysin+), (EF+,MRP+, suilysin-), (EF+, MRP-, suilysin-) and others. S. suis from the states of Santa Catarina and São Paulo showed the presence of seven and six different genotypes, respectively, which suggests the genetic diversity of Brazilian isolates in these regions. Direct correlation between gene combinations and tissues examined was not possible to be drawn, but isolates from the central nervous system showed seven different genotypes, followed by lung isolates, which showed five genotypes. Differently from what have been previously described, Brazilian isolates of S. suis present different EF, MRP and suilysin distribution patterns, which can have negative effects on the efficacy of vaccination programs against this agent.
KEY WORDS:
Swine; virulence factor; streptococosis; PCR; genes
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