title: Genetic transformation in Streptococcus sanguis. Identification, surface spreading and competence of invasive strains of Streptococcus sanguis Lancefield groups H and W and other invasive viridans streptococci.
abstract: Of 46 viridans streptococci isolated from cases of probably true bacteremia, 26 strains or 56% could be grouped serologically in the Lancefield system. Eight strains (17%) were identified as serogroup H (characteristic of Streptococcus sanguis), ten strains (22%) as serogroup W (a new group antigen found in S. sanguis) and eight strains (17%) as serogroup K (related to S. mitis (mitior)). The high number of serogroupable viridans streptococci was specially due to the introduction of serogroup W and indicates the importance of this serogroup in cases of bacteremia. A set of six diagnostic tests (production of hydrogen peroxide, arginine and esculin hydrolysis, polysaccharide production, Voges-Proskauer reaction, mannitol fermentation) was used for speciation of the viridans streptococci; in addition, search for spreading zones around the colonies was included in the diagnostic procedure. Spreading zones were only present in S. sanguis and occurred more frequently in group H strains than group W strains. The 46 viridans streptococci were tested in genetic transformation. The prevalence of spontaneous competence in strains isolated from the blood was high, particularly in S. sanguis serogroup H (88%) and W (50%). For serogroup H, spontaneous competence was found as frequently among invasive strains as among carrier isolates previously studied.
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis; D000954:Antigens, Surface; D002374:Catalase / Q000378:metabolism; D006461:Hemolysis; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008353:Mannitol / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D018805:Sepsis / Q000382:microbiology*; D012703:Serotyping; D013290:Streptococcal Infections / Q000382:microbiology*; D013298:Streptococcus sanguis / Q000145:classification / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D014169:Transformation, Bacterial
chemical_list: D000942:Antigens, Bacterial; D000954:Antigens, Surface; C030659:K antigens; D011134:Polysaccharides; D008353:Mannitol; D006861:Hydrogen Peroxide; D002374:Catalase