Catalase negative Staphylococcus aureus retain virulence in mouse model of chronic granulomatous disease

Myeloperoxidase-mediated chlorination is thought to be a necessary microbicidal mechanism. The H2O2 required for this process is generated by the NADPH oxidase. Staphylococcus aureus can also produce H2O2, which is not broken down by catalase negative organisms. It has been thought that this bacterial H2O2 can substitute for cellular H2O2 in the halogenation reaction in chronic granulomatous disease (CGD) where neutrophils are lacking the NADPH oxidase. We have readdressed this issue in a mouse model of CGD using clinical isolates of catalase positive and negative strains of S. aureus. The results showed these organisms to be equally virulent and that the H2O2 they produced is insufficient to cause significant iodination, a marker for chlorination, thereby contradicting the accepted views on this subject.