Erysipelothrix rhusiopathiae

This bacterium is a slender, nonmotile, Gram-positive rod. E. rhusiopathiae causes a septic disease in pigs, swine erysipelas. The correlate in humans is now quite rare and is a recognized occupational disease. Following contact with infectious animal material, the pathogens enter body tissues through dermal injuries. After an incubation period of one to three days, the so-called erysipeloid-a hivelike, bluish-red swelling—develops at the site of entry. The lymph nodes are also affected. These benign infections often heal spontaneously and disappear rapidly under treatment with penicillin G. Laboratory diagnostic procedures involve identification of the pathogen in wound secretion using the methods of microscopy and culturing.