Mycobacterium avium-intracellulare pulmonary infection in HIV-negative patients without preexisting lung disease: diagnostic and management limitations.

STUDY OBJECTIVES: To review the experience of an outpatient pulmonary clinic with Mycobacterium avium-intracellulare (MAI) pulmonary disease in the HIV-negative population without preexisting lung disease.

DESIGN: Retrospective clinical series.

SETTING: University medical center.

PATIENTS: The clinic charts of all patients who fulfilled the current American Thoracic Society criteria for MAI pulmonary infection and who had no preexisting lung disease or immunosuppression were reviewed.

MEASUREMENTS AND RESULTS: Of 31 patients identified, 94% were female, 90% were white, and the median age at diagnosis was 63 years. The median time interval from symptom onset to diagnosis was 10 months. Bronchiectasis or small nodules without predilection for any lobe was found in 93%. Bronchoscopy or open lung biopsy for diagnosis was required in 45% because of nondiagnostic sputum cultures. At > or = 12 months, 50% failed therapy, 86% continued to be symptomatic, and 58% did not tolerate their initial multidrug regimen.

CONCLUSIONS: These results emphasize the observed chronic nature of MAI pulmonary disease in this population, both before diagnosis and despite therapy. The sensitivity of sputum culture in this population is low, so an aggressive diagnostic approach, including bronchoscopy, should be considered if sputum cultures are negative. Current treatments are suboptimal because of poor drug tolerance and significant failure rates. Last, the preponderance of disease in older white women argues for a genetic or acquired immune deficiency to explain disease susceptibility.