Construction and virulence testing of a collagenase mutant of Clostridium perfringens

Clostridium perfringens produces several extracellular toxins and enzymes, including an extracellular collagenase or kappa toxin that is encoded by the colA gene. To determine if the ability to produce collagenase was a significant virulence factor in cases of gas gangrene or clostridial myonecrosis that are caused by C. perfringens, a chromosomal colA mutant was constructed by homologous recombination and subsequently virulence tested in the mouse myonecrosis model. The results clearly indicate that loss of the ability to produce collagenase does not alter the ability of the mutant to establish a virulent infection. By contrast, infection with a mutant unable to produce alpha-toxin led to a marked decrease in virulence. These results indicate that collagenase is not a major determinant of virulence in C. perfringens -mediated clostridial myonecrosis.