Fatal case of disseminated infection with the turtle bacillus Mycobacterium chelonae

An apparently immunocompetent 78 year old woman presented with confusion, subcutaneous abscesses, and lesions of the nasopharynx. Gram positive, acid fast bacilli were isolated from her blood after 10 days' incubation. She was treated with trimethoprim-sulphamethoxazole for presumed disseminated nocardiasis but deteriorated and died. A post mortem examination showed skin and pulmonary lesions and endomyocardial fibrous plaques. Organisms isolated from the skin and lung were indistinguishable from those cultured from the blood. The organism was subsequently identified as Mycobacterium chelonae. Primary pulmonary infection and disseminated disease are rarely caused by this organism and bacteraemia is seldom documented. The clinical presentation and bacteriological and histological findings are difficult to differentiate from those of disseminated nocardiasis. Isolation of the organism may fail without prolonged incubation of initial cultures and there is a danger of its being dismissed as medically unimportant. Diagnosis is further hampered because large pulmonary foci may be poorly revealed by conventional radiological examination of the chest.