Nocardia elegans infection involving purulent arthritis in humans.

Nocardia elegans infection in humans is rare and is predominantly associated with pulmonary infections. We describe the first case of N. elegans infection associated with purulent arthritis in humans. The patient was a 66-year-old woman without underlying disease. She had swelling in her left ankle that was increasing in size, but it did not cause the patient substantial pain. Punctual discharge was collected for Gram staining and Kinyoun's acid-fast staining. The results of microscopic findings were suggestive of the genus Nocardia. The 16S rRNA sequence of the isolate was completely identical (100%) with that of N. elegans, indicating that the isolate was N. elegans. All the previously reported 4 cases of N. elegans infection in humans were associated with respiratory infections; we present the first case of the infection involving purulent arthritis.