Corynebacterium infections

STEPHANIE SPECK

B undeswehr Institute of Microbiology, Department of Virol­ogy and Rickettsiology, Munich, Germany

Corynebacteria are pyogenic bacteria causing a variety of suppurative infections.

Corynebacteria are Gram-positive small pleomorphic rods of about 0.5 μm in width that occur in rod, coccoid, club and filamentous shapes. They are non-spore-forming, non-acid-fast, catalase-positive, oxidase-negative and usually facultatively anaerobic, and the animal pathogens are non- motile. In some Corynebacterium species virulence is attrib­uted to toxins such as phospholipase D (PLD)⁽⁴³⁾.

Corynebacteria have been isolated from a variety of environments and clinical sources. They also occur as part of the indigenous flora of animals, but there is less infor­mation on the nature of these corynebacterial species, their host distribution¹-⁴⁴) and virulence. Members of the C. renale group, C. renale, C. cystitidis and C. pilosum, belong to the normal flora of the urogenital tract of animals. All hydrolyse urea and possess pili, which mediate adherence to host epithelial cells of the urogenital tract. They are opportunistic pathogens, causing purulent cystitis and pyelonephritis sporadically, in particular in cattle. Coryne- bacterium cystitidis causes posthitis, preputial ulcerative dermatitis, and ulcerative vulvovaginitis in sheep and goats. Corynebacterium pseudotuberculosis causes caseous lymphadenitis in sheep and goats and abscesses in various domestic animals. Corynebacterium ulcerans causes mastitis in cattle and may infect humans consuming raw milk; expression of its toxic PLD is important in the pathogen­esis of infection.

Only few data about Corynebacterium species associated with disease in wild mammals have been reported. Coryne- bacterium ulcerans was isolated from the lungs of two free- ranging otters (Lutra lutra) found dead in the UK. This was the first report of C. ulcerans in otters, but the agent was not regarded as the primary cause of death. However, further studies are necessary to determine the host range of C. ulcerans⁽⁴⁵⁾.

Members of the C. renale group were isolated from male European bison bulls suffering from balanoposthitis. Corynebacterium caspium has been associated with severe suppurative balanoposthitis and necrosis of the mucosa of the penis and prepuce in a Caspian seal (Phoca caspica) infected with canine distemper virus⁽³⁶⁾.