LAUSR

Erysipelothrix rhusiopathiae is a commensal Grampositive bacterium. This organism may cause disease in humans after direct contact with infected animals, notably swine, usually leading to a localised skin infection called erysipeloid. Systemic infection with or without endocarditis is less frequently observed. Involvement of joints is rarely reported. Here, we describe a patient with septic polyarthritis caused by E. rhusiopathiae infection. In 2018, a 57-year-old woman was admitted to our unit with a 7-day history of polyarthritis. The patient had been followed for sarcoidosis with cutaneous and pulmonary involvement since 1989, and the disease was in remission on hydroxychloroquine treatment. She underwent a right distal femoral osteotomy in 2010. In 2017, she had an episode of polyarthritis secondary to calcium pyrophosphate deposition disease (CPPD) that was treated with high-dose corticosteroids (30 mg/day). In error, corticosteroids were not reduced and the patient had remained on the same treatment at the time of admission in 2018. Clinical exam revealed swollen knees and wrists but no fever or skin lesions. The patient did not have any pets and did not eat pork. Blood tests revealed an elevated Creactive protein (CRP) level of 66 mg/L. Ultrasonography revealed effusion in the knees and synovitis in the wrists. Joint fluid of the knees was inflammatory, with a white blood cell count from 30 000 to 92 000 cells/mm and Gram-positive bacilli. Synovial fluid and blood cultures were positive for E. rhusiopathiae. Echocardiography gave normal results, but joint X-rays showed chondrocalcinosis. The patient received amoxicillin (6 g/day intravenous for 15 days) followed by levofloxacin (500 mg/day) for 4 weeks. Corticosteroids were progressively decreased to 5 mg/day. The antibiotic treatment allowed for substantial improvement, with a decrease of joint symptoms and CRP level. Here, we report a patient with a septic infection of native joints caused by E. rhusiopathiae infection.