Growth-Phase-Dependent Expression of Virulence Factors in an M1T1 Clinical Isolate of <i>Streptococcus pyogenes</i>

Abstract

The effect of growth phase on expression of virulence-associated factors was studied by Northern hybridization in an M1T1 clinical isolate of Streptococcus pyogenes. Expression of M protein, C5a peptidase, and capsule was maximal in the exponential phase of growth, while streptococcal pyrogenic exotoxins A and B and mitogenic factor were maximally expressed in later phases of growth.