Erysipelothrix rhusiopathiae: bacteriology, epidemiology and clinical manifestations of an occupational pathogen

Erysipelothrix rhusiopathiae has been recognised as a cause of infection in animals and man since the late 1880s. It is the aetiological agent of swine erysipelas, and also causes economically important diseases in turkeys, chickens, ducks and emus, and other farmed animals such as sheep. The organism has the ability to persist for long periods in the environment and survive in marine locations. Infection in man is occupationally related, occurring principally as a result of contact with animals, their products or wastes. Human infection can take one of three forms: a mild cutaneous infection known as erysipeloid, a diffuse cutaneous form and a serious although rare systemic complication with septicaemia and endocarditis. While it has been suggested that the incidence of human infection could be declining because of technological advances in animal industries, infection still occurs in specific environments. Furthermore, infection by the organism may be under-diagnosed because of the resemblance it bears to other infections and the problems that may be encountered in isolation and identification. Diagnosis of erysipeloid can be difficult if not recognised clinically, as culture is lengthy and the organism resides deep in the skin. There have been recent advances in molecular approaches to diagnosis and in understanding of Erysipelothrix taxonomy and pathogenesis. Two PCR assays have been described for the diagnosis of swine erysipelas, one of which has been applied successfully to human samples. Treatment by oral and intramuscular penicillin is effective. However, containment and control procedures are far more effective ways to reduce infection in both man and animals.