[Primary Mycobacterium avium respiratory infection in nonimmunocompromised children]

Mycobacterium avium is a common pathogen in barnyards, where it infects poultry and pigs. In human beings M. avium is most often found to cause disease in immunocompromised individuals, although it is also described fairly often as affecting patients with tuberculosis or chronic obstructive pulmonary disease; in recent years lung infections by M. avium have even been reported in elderly women with no underlying disease. Respiratory infection by this mycobacterium is unusual, however, in healthy children. We describe the case of a previously healthy 2-year-old boy with pneumonia whose course was complicated. After 6 months of treatment with various broad spectrum antibiotics there was no clinically or radiologically observable improvement. Other underlying diseases were ruled out, including infection by germs that cause atypical pneumonia. When all tests were negative, we investigated the possibility of primary infection by an atypical mycobacterium. A skin test was positive for M. avium. Acid-alcohol resistant bacilli were isolated from lung biopsy samples and the presence of tuberculoid granulomas were confirmed. Our patient then responded favorably after tuberculostatic treatment with 3 drugs (isoniazid, rifampicin and pyrazinamide).