[The hydrophobicity of Streptococcus pyogenes as a possible marker of its virulence].

The hydrophobicity of 366 S. pyogenes cultures isolated from the pharynx of tonsillitis and scarlet fever patients and healthy children, as well as museum strain of type M29, was studied. The study revealed that the hydrophobicity of cultures isolated from scarlet fever patients exceeded that of cultures isolated from healthy carriers and tonsillitis patients. Among S. pyogenes cultures isolated in cases of prolonged carriership a considerable proportion of highly hydrophobic cultures was detected, which was probably indicative of an important role played by the hydrophobicity of streptococci in retaining them on the barrier epithelium. This was confirmed by the presence of correlation between the hydrophobicity of culture of S. pyogenes, type M29, and its adhesion to the fibronectin receptor and HEp-2 cells. For S. pyogenes of type M6, epidemic in the group of children under observation during the period of 1987-1988, the values characterizing its hydrophobicity were registered which significantly exceeded average hydrophobicity values. At the period of a rise in morbidity S. pyogenes cultures were characterized by significantly higher hydrophobicity. The variability of the hydrophobicity index and its relationship with the dissociation of cultures were established. The hydrophobicity index may be used as one of the virulence markers of S. pyogenes strains.