Table 1.

Alab49 mutants having a statistically significant decrease in virulence relative to wild-type, when tested in the humanized mouse model for superficial skin infection.

Mutant	Function of gene product	Control of gene transcription	Cell association	Virulence at skin (log inoculum)†	Virulence at skin (stat inoculum)†
Δmga	Transcriptional regulator	Autoregulated (activated)‡	Cytoplasm	Decreased	Decreased
Δnra	Transcriptional regulator	Autoregulated (activated)‡	Cytoplasm	Decreased	Decreased
Δpam (Δemm53)	Plg-binding M protein	Activated by mga	Surface	N.D.	Decreased (partially)
Δska	Plg activator (streptokinase)	No effect by mga	Secreted	N.D.	Decreased (partially)
ΔspeB	Cysteine protease	Activated by mga (indirect)	Secreted	Decreased	Decreased
ΔfctA	Pilus backbone subunit	Activated by nra	Surface	No effect	No effect
Δcpa	Collagen-binding protein (pilus)	Activated by nra	Surface	Decreased	No effect
ΔprtF2	Fn-binding protein	Activated by msmR	Surface	Decreased	No effect

^†Virulence at the skin was measured for group A Streptococcus inoculum cultures grown to either log or stationary phase in enriched broth.

^‡Assumed but not completely proven for strain Alab49; Mga and Nra function as autoregulators in other strains [37].

Fn: Fibronectin; N.D.: Not determined.