Septic Arthritis Caused by Rothia dentocariosa in a Patient with Rheumatoid Arthritis Receiving Etanercept Therapy

To the Editor: Rothia dentocariosa is a pleomorphic gram-positive rod normally found in the human mouth that has been associated with dental cavities, periodontal disease1, and, rarely, as a cause of systemic infection2,3. We describe a case of septic arthritis due to R. dentocariosa in a 46-year-old woman admitted to our Rheumatology Unit in December 2008. She had been diagnosed with polyarticular rheumatoid arthritis (RA) 10 years before, and for 2 years arthritis was treated with etanercept (25 mg twice weekly) and oxaprozin. She underwent a meniscectomy and synovectomy of the right knee in March 2008. Tumor necrosis factor (TNF) inhibitor was stopped 2 weeks before and started again 2 weeks after surgery. Levofloxacin was administered for 2 weeks after surgery. Three months later the knee suddenly became swollen and painful. The patient had no fever; laboratory investigation showed only a mild increase of erythrocyte sedimentation rate (ESR; 57 mm/h). Arthritis was diagnosed as a rheumatoid flare and treated with corticosteroid infiltrations, unsuccessfully, with no other therapeutic change. On admission, … Address correspondence to Prof. Schiavon; E-mail: f.schiavon{at}unipd.it