FGF2 and gas gangrene: A previous study aimed to increase the efficacy of bFGF by adding collagen-binding domains from mammalian collagenase, von Willebrand factor, and Clostridium collagenase to bFGF to enhance its collagen-binding ability [9–12]. Clostridium histolyticum, a pathogenic bacterium of gas gangrene, secretes two classes of collagenase (class I, ColG; class II, ColH).