Mycobacterium aviumComplex Pulmonary Disease: Incidence, Presentation, and Response to Therapy in a Community Setting

Abstract

The experience with pulmonary disease caused by Mycobacterium avium complex (MAC-PD) was examined over a 12-yr period in a nonreferral setting. The 29 patients with the disease constituted 30% of all pleuropulmonary mycobacterioses. The mean annual incidence rate was 1/100,000. Sixty-two percent of patients were female, the majority of whom had no discernible preexisting pulmonary disorder to account for their susceptibility. A short- and long-term favorable response to therapy was observed in more than 90% of the 16 patients treated with intent to cure. Suggested as plausible explanations for the favorable response rate compared with previous studies originating in referral settings were: absence of adverse selection as shown by a smaller proportion of patients with far-advanced cavitary disease or with previous treatment failure, and a larger proportion of female patients. A previously unreported pattern of MAC-PD was observed: disease limited to the lingula or middle lobe occurred in 21% of the patients, all female. A rarely identified pattern, primary disease in a 3-yr-old exposed to pet birds, is reported.

A Rhesus Macaque Model of Pulmonary Nontuberculous Mycobacterial Disease

“…Interestingly, disease was limited to the right caudal lobe (site of initial infection), and did not disseminate to the left lobe or systemically. This recapitulates human disease, where MAC is often first identified and then remains limited within the right middle lobe or lingula for months or years without disseminating from the lung (17,18), and sometimes resolving either spontaneously or during antibiotic therapy upon repeat imaging 3-6 months later (4). It is unclear if this animal would have spontaneously resolved this infection.…”

“…In addition, MAC is often first identified and limited within the right middle lobe or lingual in human disease (17). To ensure a successful recapitulation of PNTM in our animal model, three bilaterally oophorectomized female rhesus macaques (12-13 yr old) were inoculated with escalating doses of MAC in the right caudal lung.…”

Clinical and Prognostic Importance of Serotyping Mycobacterium avium-Mycobacterium intracellulare Complex Isolates in Human Immunodeficiency Virus-Negative Patients

“…The cases of pulmonary disease caused by MAC occurred in immunologically healthy adults and could not be regarded as opportunistic infections. However, only a few detailed studies on the clinical course of MAC cases in immunocompetent patients have been reported (14,28,29,30,33). The American Thoracic Society announced in 1997 that the natural history of MAC lung disease is unpredictable in immunocompetent patients.…”

Nontuberculous Mycobacterium Infections in Rheumatoid Arthritis Patients

“…Cavitations typically include thick walls and no air-fluid level, and are often associated with pleural thickening, which is more extensive than that seen in TB. However, pleural effusion and substantial lymph node enlargement are less common than in TB (Albelda et al, 1985;Christensen et al, 1981;Reich & Johnson, 1991;Woodring et al, 1987) (Fig. 1).…”