Malignant oedema/gas gangrene group of Clostridium spp.

The members of this ubiquitous group of bacteria (Table 1) which are individually discussed in Clostridium chauvoei infections, Clostridium novyi infections, Clostridium septicum infections and Other clostridial infections, most commonly cause gas gangrene or malignant oedema and less often a number of other syndromes in livestock (Table 1). In rare instances clostridia not contained within this group of organisms, such as Clostridium perfringens types A and C, may also be associated with gas gangrene as a consequence of wound infection.

The Clostridium spp. included in this group occur commonly in soil, sewage, marine sediments, and decaying animal and vegetable material. They are obligate anaerobes, saccharolytic and proteolytic, and most are also capable of lowering the redox potential of the medium in which they grow, thus creating a suitable environment for continuing growth.¹ They produce a variety of major and minor toxins in various combinations, the in vitro and in vivo action of some of which are poorly understood despite the fact that most have been characterized chemically and biochemically.

The diseases caused by infections with these bacteria are characteristically rapid in onset, and are highly fatal primarily due to severe toxaemia caused by both the products they elaborate and those which arise following tissue breakdown. They usually occur sporadically, often affecting single or small groups of animals, and most may be effectively controlled by immunization. Wound infection which progresses to malignant oedema or gas gangrene may result from infections with any one or a combination of the clostridia in this group and is commonly the consequence of contamination of traumatic lesions in the skin. Gangrenous lesions may also occur in genital or gastrointestinal tracts following infection of wounds with some of the clostridia species that belong to the group.

There are exceptions to the foregoing, however, examples of which are those diseases that arise as a consequence of dormant infections such as blackquarter in cattle in which the lesions are usually localized in the larger striated muscle groups, black disease and bacillary haemoglobinuria where the primary lesions are necrotic foci in the liver, braxy in which the primary lesions occur in the abomasum, and necrotic enteritis of foals caused by Clostridium difficile. In most cases of wound infection the lesions are restricted to the subcutaneous tissues and are seen as extensive gelatinous inflammatory infiltrates which may be virtually colourless, yellowish-brown or red-tinged due to the presence of concurrent haemorrhage. The exudate may on occasion contain varying numbers of gas bubbles, which impart an unpleasant odour to it; in some infections, such as those by Clostridium sordellii, the odour is particularly foul and in the case of blackquarter in cattle it resembles that of rancid butter.

Reference

1. CATO, E.P., GEORGE, W.L. & FINEGOLD, S.M., 1986. Clostridium. In: Bergey’s Manual of Systematic Bacteriology. Baltimore: Williams & Wilkins.

Table 1 Disease conditions of livestock associated with the malignant oedema/gas gangrene group of clostridia