Erysipelothrix rhusiopathiae - Bacteria

Erysipelothrix rhusiopathiae

      rhusiopathiae is a slender, straight or slightly curved, Gram-positive bacillus with a tendency toward formation of long filaments. It is nonmotile, nonsporing, and noncapsulated. It is catalase negative. It ferments glucose and lactose, producing acid but no gas. It is H₂S negative. It is MR, VP, indole, urease, and nitrate reduction test negative. It is aerobic and facultative anaerobic. The growth is improved in the presence of 5–10% CO₂.

·           It can grow on nutrient agar and also on blood agar. After 24–48 hours of incubation, it produces convex and translucent colonies surrounded by a variable zone of alpha-hemolysis.

·           On tellurite agar, it produces black colonies.

      rhusiopathiae occurs as a saprophyte in soil, food, and water.It occurs as a natural parasite of swines, mice, rabbits, turkeys, and many other animals.

      E. rhusiopathiae in humans causes septicemia, endocardi-tis, and erysipeloid. The latter is a localized infection of the skin that resembles streptococcal erysipelas. These cutaneous lesions are painful, edematous, and erythematous. They usu-ally occur on the hands or fingers of persons handling animals, fish, or animal products. The cutaneous lesions are usually associated with arthritis, lymphopharyngitis, or lymphadenitis.

      Diagnosis  of  the  condition  is  made  by  the  isolation  of rhusiopathiae from pus and other clinical specimens by culture.The bacillus is sensitive to penicillin, erythromycin, ampicillin, methicillin, ciprofloxacin, and clindamycin.