The authors report a patient with a rare manifestation of invasive septic Erysipelothrix rhusiopathiae infection without endocardial involvement. Our patient presented with progressive paraparesis and subacute fever for ten days. He had underlying diabetes mellitus and alcoholic cirrhosis. Magnetic resonance imaging (MRI) of the lumbosacral spine showed a psoas abscess with vertebral osteomyelitis and discitis at level of L2-3 of the lumbar spine. His blood culture grew E. rhusiopathiae. Transthoracic echocardiography demonstrated normal endocardium. Surgical drainage and debridement with concomitant intravenous antibiotics administration resulted in clinical improvement, including neurological status. MRI showed resolution of the psoas abscess and osteomyelitis. Erysipelothrix infection should be considered as a causative pathogen of musculoskeletal infection in immunocompromised patients. To our knowledge, this is the first case report of psoas abscess caused by E. rhusiopathiae in Thailand.

Keywords: Erysipelothrix rhusiopathiae, Bacteremia, Psoas abscess, Abscesses in paravertebral space, Epidural abscess, Osteomyelitis