Septic arthritis due to Serratia species was seen in four users of
intravenous heroin. In all cases, the organism was cultured from joint
aspirates. Both the clinical presentation and the involvement of the
sacro-iliac and knee joints were notably similar to the Pseudomonas septic
arthritis encountered in other heroin users. All four patients responded
satisfactorily to therapy although one had a residual flexion contracture
of the knee. Twelve previously reported cases of Serratia arthritis are
reviewed.