Non-TB mycobacterial infections in patients with non-CF bronchiectasis

Background Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms. Data about NTM in patients with non-CF bronchiectasis are limited. Methods In a retrospective study, data was collected on patients with bronchiectasis and patients who were diagnosed with NTM were identified. All patients diagnosed with bronchiectasis (code 494) using the International Classification of Diseases, ninth revision (ICD-9), between 1999 and 2006, were identified. Clinical data including radiology findings, lung function, progression of disease, and the presence of NTM in sputum were collected for those who met the study criteria. Results 300 patients with ICD code for bronchiectasis were found in the data. Of these, 182 patients were enrolled in the study after confirmation of the radiology findings of bronchiectasis by CT scanning. Patients were divided into two groups: bronchiectasis with NTM isolates ( n = 68) and bronchiectasis without NTM isolates ( n = 114). The clinical data was reviewed to define the clinical characteristics of these patients; 12% of the patients were found to have NTM from their sputum or BAL. Of the total patients, 55 (30%) of these met the American Thoracic Society criteria for the diagnosis of NTM disease. Mycobacterium avium complex (MAC) was the most common isolate. It was found that the probability of NTM isolation was significantly higher in elderly female patients ( p = 0.04) with a low body mass index (BMI) ( p = 0.002). Additionally, it was found that gram-negative rods were frequently isolated in these patients, and the frequency of exacerbations was significantly higher in patients with NTM infections. Conclusions NTM infections are common in non-CF bronchiectasis. MAC is the most frequently isolated NTM in these patients. Elderly female patients with a low BMI are a high-risk group for NTM infection in non-CF bronchiectasis. Furthermore, these patients are prone to secondary infections and frequent exacerbations. This study suggests a strong correlation between non-CF bronchiectasis and NTM. Thus, these patients should be routinely screened for NTM infections.