BRD3 and infection: To assess whether the decreased survival of the ΔorfX strain was due to the increased oxidative response of macrophages, we treated the cells with the antioxidant trolox before infection with the wild-type EGDe strain, the EGDeΔorfX mutant, or the complemented EGDeΔorfX strain producing OrfX, and the numbers of intracellular bacteria were determined 8 h postinfection.