Clostridium chauvoei infections

N P J KRIEK AND M W ODENDAAL

GENERAL INTRODUCTION: ENDOSPORE-FORMING GRAM-POSITIVE RODS AND COCCI Malignant oedema/gas gangrene group of Clostridium spp.

Introduction

Blackquarter in cattle arises as a consequence of the activation of spores of Clostridium chauvoei latent in the musculature. Clostridium chavoei may also cause gas gangrene in cattle, sheep, and goats, and rarely in horses and pigs following wound infection.^{21, 33, 36, 42} These infections cause a peracute or acute, usually fatal, non-contagious disease which is characterized by focal, gangrenous myositis and associated localized cellulitis. Death is caused by the local and systemic effects of the toxins elaborated by C. chauvoei. In this chapter the use of the term ‘blackquarter’ is restricted to that condition in cattle which arises as a result of endogenous C. chauvoei infection, whereas the lesions that develop as a consequence of wound infections by this organism in various animal species, including cattle, are referred to as gas gangrene.

Blackquarter is a universal disease of cattle. It was recognized as a distinct disease in 1782 by Chabert who named it ‘charbon symptomatique’ (quoted by Henning²⁵) and distinguished it from anthrax with which it was often confused. Later the disease and the properties of the causal organisms were studied by Arloing, Cornevin and Thomas,² who also developed the first practical method of prophylactic immunization. ³⁷

It would appear that in South Africa blackquarter was one of the most prevalent diseases of cattle from the time of the earliest European settlement of the Cape. Thus, as early as 1780, Le Vaillant³¹ described the disease as a ‘terrible scourge, spons-siekte (literally ‘‘sponge disease’’), which causes speedy destruction of more than half the herd’. The first official reference to the occurrence of blackquarter in South Africa was made by Commissioner De Mist in 1805.⁴⁸

Immunization against blackquarter has been practised since before the turn of the eighteenth century. As early as 1883 blackquarter powder vaccine was imported into Natal by Wiltshire. The first effective blackquarter vaccine in South Africa was prepared in 1887 at the Grahamstown Laboratory in the Cape Province.²⁵

In spite of the effective vaccines available today, sporadic outbreaks and individual cases of the disease are still regularly encountered in livestock in southern Africa and blackquarter remains one of the important bacterial diseases of cattle under three years of age, particularly those in feedlots. For this reason cattle should be regularly immunized against this infection.

Aetiology

Clostridium chauvoei is a Gram-positive anaerobic rod, 3 to 8 μm long and 0,5 to 1 μm wide. When grown in fluid media the organisms are most commonly found as single cells, but sometimes occur in pairs and, rarely, in short chains. The cells are motile and have peritrichous flagella. In older cultures they are pleomorphic, showing irregular staining; citron, barred and spindle shapes occur frequently. Spores, which are are formed when the organism is cultured on solid media and in broth, are oval, occur in central or subterminal positions, and distort the shape of the cell. They are resistant to the effects of being boiled in water as well as to phenolic and quaternary disinfectants at concentrations used to sterilize contaminated instruments.^{5, 43}

Clostridium chauvoei grows well in peptone-yeast-glucose broth, in which, after four days of incubation, the pH decreases to 5,0 to 5,4. The optimum temperature for growth is 37 °C; poor growth is obtained at between 25 and 30 °C, but no growth occurs at 45 °C. The addition of liver extract to the medium favours growth which is also stimulated by fermentable carbohydrates. Growth is inhibited by concentrations of NaCl above 6,5 per cent as well as by bile levels of 20 per cent or higher; pH values of 8,5 or higher also inhibit growth.

Surface colonies on blood agar are circular, 0,5 to 3 mm in diameter, haemolytic, slightly raised or low convex, whitish-grey, translucent or opaque, and granular with a glossy surface and an entire margin. Red blood cells of cattle, sheep, pigs, rabbits and dogs are readily haemolysed by C. chauvoei on blood agar, whilst those of guinea pigs, horses, humans, and chickens are more resistant.

Clostridium chauvoei has fastidious anaerobic growth requirements. It is saccharolytic, non-proteolytic and does not produce lecithinase and lipase. Lactose, galactose, mannose, glucose, maltose and sucrose are fermented, esculin is hydrolysed by 90 to 100 per cent of strains, and ribose by 40 to 60 per cent of strains, while nitrate is reduced by 61 to 89 per cent of strains. No starch is hydrolysed nor is acid produced from amygdalin, arabinose, cellobiose, fructose, glycogen, inositol, mannitol, melezitose, melibiose, raffinose, rhamnose, salicin, sorbitol, starch, trehalose and xylose. Meat is not digested by 90 to 100 per cent of strains.^{10, 35} Large volumes of gas (carbon dioxide and hydrogen) are produced in liquid media. The organism has a high demand for cysteine, biotin, nicotinic acid, pantothenic acid, pyridoxamine, thiamin and para-aminobenzoic acid.⁴¹

Clostridium chauvoei produces protein toxins and other protective antigens in amounts which vary with the strain. Both bacteria and the filtrate of fluid media in which they have been grown are immunogenic.^{13, 14, 46} Whole...