Background and objective: Mycobacterium marinum (M.m.) is the causative pathogen of skin infections that have been called "swimming pool granulomas". An increasing number of reports that deep structures are involved in these infections was the reason for studying the clinical presentation and response of the infection to different therapeutic regimens.
Patients and methods: All patients (eight men, four women, age range 18-73 years) were included in whom, between january 1991 and February 1995, M.m. infection had been proven by culture. The clinical data of these patients were retrospectively obtained by standardized questionnaire.
Results: The infection was limited to the skin in four of the twelve patients, deep structures only were involved in three, and five had both. Infections limited to the skin were successfully treated with sulphamethoxazole and trimethoprim or with tetracyclines, while rifampicin, alone or in combination with ethambutol, was efficacious when deep structures were involved. No surgical intervention was--or should be--performed.
Conclusions: Infections with M.m. often involve deep structures, even in the absence of the skin being involved. The term "swimming pool granuloma" is, therefore, misleading when the infection is limited to he skin. A history of a chronic and indolent course, frequent changes of doctor and striking polypharmacy in its treatment are pointers to this infection.