In vivo and in vitro analysis of Bordetella pertussis catalase and Fe-superoxide dismutase mutants

Bordetella pertussis produces a catalase and a Fe-superoxide dismutase. The importance of these enzymes in virulence was investigated, in vitro as well as in vivo, by using mutants deficient in their production. The catalase-deficient mutant survived within polymorphonuclear leukocytes, killed 5774A.1 macrophages through apoptosis, and behaved as the parental strain in a murine respiratory infection model. These results suggest no direct role for catalase in B. pertussis virulence. The absence of expression of Fe-superoxide dismutase had profound effects on the bacterium including a reduced ability to express adenylate cyclase-hemolysin and pertactin, two factors important for B. pertussis pathogenesis. The Fe-superoxide dismutase-deficient mutant also had decreased abilities to colonize and persist in the murine respiratory infection model.