Role of catalase in the virulence of Brucella melitensis in pregnant goats.

An isogenic katE mutant derived from virulent Brucella melitensis 16M displays hypersensitivity to hydrogen peroxide in disk sensitivity assays but retains the capacity to colonize pregnant goats and induce abortion. These experimental findings indicate that although the sole periplasmic catalase of Brucella melitensis functions as an antioxidant, this enzyme does not play a critical role in virulence in the natural host.