FIG 1.

Changes in Cu levels during GAS infection and the effect of a copA mutation on GAS virulence in host infection models. (A) Cu levels in mouse lesions. Mice were infected subcutaneously with GAS wild-type strain or left uninfected (n = 10 each). After 3 days, skin from uninfected mice, and both skin lesions and healthy skin adjacent to the lesions from infected mice were excised. Total Cu levels were measured by ICP-MS and normalized to the weight of the tissues. Cu levels in infected lesions were higher than those in adjacent healthy skin (P < 0.0001) or skin from uninfected mice (P < 0.0001). (B) Cu levels in mouse blood. Mice were infected subcutaneously with GAS wild-type strain or left uninfected (n = 10 each). Blood was collected and total Cu levels were measured by ICP-MS. Values below the detection limit were represented as zero. Cu levels in the blood of infected mice on days 1 and 3 were higher from those in the blood of uninfected mice (***, P = 0.0001; ****, P < 0.0001). ns, P = 0.81 (versus uninfected mice). (C) Virulence in an in vivo mouse model of infection. Mice were infected subcutaneously with GAS wild-type (WT) or ΔcopA mutant strains (n = 10 each). The number of surviving mice was counted daily up to 10 days post-infection. Differences in survival curves were analyzed using the Mann-Whitney test, which found no statistical difference (P = 0.099). (D) Virulence in an ex vivo human neutrophil model of infection. Human neutrophils were infected with GAS wild-type (WT), ΔcopA, or copA⁺ strains (n = 3 each). Survival of bacteria relative to the input was measured after 0.5 h. There was no difference between survival of the ΔcopA mutant compared with the WT (P = 0.87) or copA⁺ (P = 0.35) strains.