Erysipelothrix rhusiopathiae: An important cause of bacterial disease in farmed pigs and an occupational pathogen of humans

Erysipelothrix rhusiopathiae is a Gram-positive bacillus that is found ubiquitously in the environment. It is known to colonise a wide range of animals, most commonly farmed pigs, turkeys and hens, in which it can cause pathology. The disease swine erysipelas affects growing pigs, significantly impacting pork production, and so its early detection and control is economically important. Infection of humans with E. rhusiopathiae is primarily associated with occupational exposure and most often results in a localised skin infection called erysipeloid. More severe infections can cause serious illness and even death in both animals and humans. The accurate identification of E. rhusiopathiae is often dependent on the inclusion in the clinical history of relevant information regarding exposure. Since the bacterium is often mistaken for other species of Gram-positive bacillus this ensures that appropriate differential tests are required. There are confirmed cases of E. rhusiopathiae infection in individuals with no reported animal exposure so it is possible that there are other modes of transmission. Regarding treatment regimens, E. rhusiopathiae is intrinsically resistant to vancomycin but susceptible to penicillins and carbapenems.