Septic arthritis involving Capnocytophaga ochracea.

Septic arthritis of the knee developed in a 21-month-old child. The causative organism, isolated from two separate arthrocenteses, was identified as Capnocytophaga ochracea morphologically and by biochemical reactions. Previous human infections (bacteremias) have occurred in granulocytopenic hosts with concomitant oral pathology including periodontitis and gingivitis. No abnormalities of oral hygiene were present in this patient, and granulocyte numbers were normal or elevated. Eradication of the infection was accomplished with 8 weeks of antibiotic therapy combined with surgical drainage. Septic arthritis expands the spectrum of infections reported to be caused by Capnocytophaga spp.