FIGURE 4.

Role of the npx locus in response to H₂O₂. (A) Survival of GBS after 1 h exposure to 5 mM H₂O₂ alone or in combination with pH 4.5. Survival is expressed as the percent of CFU after exposure relative to the untreated control. (B) The level of H₂O₂ detoxification by GBS at two different H₂O₂ concentrations. Percent detoxification was calculated by normalizing the amount of H₂O₂ remaining after incubation with GBS to the amount of H₂O₂ in the culture free control. Data shown is average ± SD of three separate biological replicates (^∗P < 0.05, ^∗∗P < 0.01, ^∗∗∗P < 0.001).