Septic Arthritis and osteomyelitis caused by an organism of the genus Rhodococcus

We describe a previously healthy, immunologically normal young girl who presented painless swelling of fingers, a toe, and one knee. Roentgenograms were consistent with osteomyelitis of the phalanges and knee effusion. Rice bodies (corpora oryzoidea) were identified in viscous fluid obtained from the knee during arthroscopy. Culture of this fluid grew an organism initially believed to be a member of the genus Nocardia but which was later presumptively identified as a member of the genus Rhodococcus. The patient was successfully treated with a combination of erythromycin and amoxicillin for a total of 6 months. Previously reported cases of this unusual infection and the microbiological features of the organism are reviewed. The significance of rice bodies found in joint fluid and the therapy of this infection are discussed.