Clostridia in gas gangrene.

The rapidly progressive infections of muscle brought about by some members of the genus Clostridium have been investigated by a number of workers during the past ten years. In general, such investigations fell into three groups: investigations of the clostridia found in war wounds and the factors that affect their growth; investigations of the exocellular toxins produced by the pathogenic clostridia and the relation of these toxins to virulence; and investigations of the effect of chemotherapeutic agents on clostridia. Local defense mechanisms of the host appear to play no part in gas gangrenethese infections seem to be primarily the result of an actively growing organism invading a relatively passive host. Much interest has been shown in the toxic exocellular products of the pathogenic clostridia, for the activity of the organisms is largely a reflection of the exocellular toxins produced by them. With regard to the role that such products play in these infections, MacFarlane and Knight (48) have pointed out that in searching for biochemical mechanisms by which bacterial toxins affect the cells of the host, two main hypotheses should be considered: first, the toxin may be a substance which blocks a metabolic reaction of the host by interfering with an essential enzyme system; and second, the toxin may be an enzyme itself, exerting its toxic action by attacking one or more specific substrates which are normal constituents of the cells of the host and which are accessible to the enzyme. Gale (30) has presented an excellent discussion of C. perfringens infections from this point of view. Since the progress of these clostridial infections seems to be governed more by the properties of the invading organisms than by the resistance of the host, it was thought that it would be interesting and perhaps informative to consider gas gangrene primarily with regard to the bacteria involved, and the factors which affect their growth in the animal body. The surgical literature on gas gangrene has been reviewed by Altemeier and Furste (5). This review is restricted, largely, to investigations carried out since the beginning of the second World War, a period when the study of clostridial infections was given impetus by the large number of cases developing in battle casualties. It was deemed desirable to limit consideration of human cases to those arising from wounds of warfare, for it was only in active theaters of war that gas gangrene occurred with sufficient frequency to make valid comparisons possible.