Table 4.

Main Streptococcus pyogenes virulence factors

Gene/genomic region/plasmid	Functional role	Comments
hasA, hasB, hasC	Hyaluronic acid capsule synthesis	Prevention of phagocytosis
emm	Antiphagocytic protein (M protein)	Sequence used for typing S. pyogenes isolates
spyCEP	Interleukin-8 protease	Inhibition of PMN leucocytes diapedesis
sda1	Streptodornase D (extracellular DNase)	Degradation of PMN DNA nets
sagA, sagB, sagC, slo	Streptolysin S and O	Lysis of red blood cells, epithelial cells, macrophages and PMN
speA, speC, speH, speI, speJ, speL/M, ssa, SMEZ	Superantigens	Involved in the pathogenesis of toxic shock syndrome or scarlet fever
speB	Cysteine protease	Tissue invasion and dissemination
fbaA, sclA	Adhesins

Adapted from Cole et al. [103] and Reglinski and Sriskandan [104]

Many low-/non-virulent isolates hold virulence factors in their genome but their expression is under strong down-regulation. Mutations in two-component systems, such as covR/S or other regulators, have been associated with a dramatic up-regulation of most of those virulence-associated genes

PMN, Polymorphonuclear.