Injection site abscesses caused by Mycobacterium chelonei.

Subcutaneous abscesses occurred at hip and deltoid injection sites in 13 student nurse assistants following practice injections. Mycobacterium chelonei was isolated from three cases and was the presumptive pathogen in other temporally clustered cases with similar clinical findings. A 1,000 cc bottle of 0.9 N saline used as a source for practice injection solution was the apparent source of the organism. Presenting findings included tenderness (7), swelling (7), fever (3), adenopathy (1) and weight loss (1). All cases were characterized by long incubation periods (6 to 16 weeks) and delayed resolution (mean 8.8 months), and required surgical drainage or wedge excision for therapy. Antituberculous therapy was administered in three cases. Complications were limited to scarring in seven cases with keloid formation in two and persistent pain in three cases. This outbreak reinforces the importance of penetrating trauma in this cutaneous mycobacterial infection and emphasizes the emergence of this organism as an important nosocomial pathogen.