Cell surface characteristics and adherence of typeable and non-typeable strains of Streptococcus suis from pig farms in Cuba

[摘要] Streptococcus suis infection is considered a major problem in the swine industry. There are 35 known serotypes of S. suis based on the capsular polysaccharides (CPS) on the cell surface. Serotype 2 is the most virulent in pigs and humans. Some S. suis strains do not agglutinate with any of the typing antisera and are identified as non-typable strains, which have generally been viewed as organisms that do not cause important clinical infections. Previous studies have shown differences in the composition and properties of the cell surface among these strains. The aim of this study included the characterization of cell hydrophobicity, ability to adhere to plates, and autolysis over time of typeable and non-typeable strains of S. suis from farms of the Cuban western region. The non-typeable strains showed a hydrophobic surface and ability of adhesion to plates. In this work, a fragment of atl gene encoding for the most important autolysine in S. suis was detected in serotypes 2, 9 and non-typeable strains. Correlation between cell adherence, hydrophobicity, and autolysis was only detected in two non-typeable strains, indicating that the non-encapsulated strain was more hydrophobic than the encapsulated strain and suggesting a potential ability to form biofilms. The ability to form biofilms is not required for virulence, but it does contribute towards long-term colonization, transmission and difficulties to eradicate these infections. These results indicated that non-typable strains should be considered when implementing measures to control the pathogenesis of the infection with S. suis in Cuban farms.

[学科分类] 兽医学

[关键词] Streptococcus suis;hidrofobicidad;adherencia;autolisina