Photoinactivation of catalase sensitizes a wide range of bacteria to ROS-producing agents and immune cells

Bacteria have evolved to cope with the detrimental effects of ROS using their essential molecular components. Catalase, a heme-containing tetramer protein expressed universally in most aerobic bacteria, plays an indispensable role in scavenging excess hydrogen peroxide (H(2)O(2)). Here, through use of wild-type and catalase-deficient mutants, we identified catalase as an endogenous therapeutic target of 400–420 nm blue light. Catalase residing inside bacteria could be effectively inactivated by blue light, subsequently rendering the pathogens extremely vulnerable to H(2)O(2) and H(2)O(2)-producing agents. As a result, photoinactivation of catalase and H(2)O(2) synergistically eliminated a wide range of catalase-positive planktonic bacteria and P. aeruginosa inside biofilms. In addition, photoinactivation of catalase was shown to facilitate macrophage defense against intracellular pathogens. The antimicrobial efficacy of catalase photoinactivation was validated using a Pseudomonas aeruginosa–induced mouse abrasion model. Taken together, our findings offer a catalase-targeting phototherapy approach against multidrug-resistant bacterial infections.