The observation that certain strains of Staphylococcus aureus differed in their virulence measured for eggs, as well as in capsule size and coagulase production, led to an investigation of the rate of release of capsular material in staphylococcus cultures. Capsular material was measured by the hemagglutination inhibition reaction. Strains of high and moderate virulence were compared. The highly virulent strain released 10 times as much capsular material as the strains of moderate virulence. The moderately virulent strains did not differ significantly in amount of capsular material formed. Parallel quantitative determinations of free coagulase revealed similar differences. The hemolytic activity of the supernatant fluids against rabbit erythrocytes, however, showed an inverse relationship to egg virulence. The visual observation of differences in capsular size was verified by measuring packed cell volume/viable count ratios for the strains studied. A positive correlation was obtained between capsule size, egg virulence, release of capsular material, and amount of coagulase produced.
No takes yet. Share an insight, caveat, or question.
Bill B. Wiley (1968) studied this question.