Bronchiectasis and Nontuberculous Mycobacterial Disease

In the treatment of patients with nontuberculous mycobacterial pulmonary disease (NTM-PD), pulmonary rehabilitation (PR) has been recommended as a non-pharmacological therapy. However, no study has validated the combination of chemotherapy and PR in this context. This study investigated the effect of chemotherapy and supervised PR on health-related quality of life (HRQoL) and physical function in NTM-PD patients.

This prospective cohort study included patients diagnosed with NTM-PD who had a planned hospitalization of at least 3 weeks for chemotherapy and PR. HRQoL (Leicester Cough Questionnaire [LCQ] and chronic obstructive pulmonary disease assessment test [CAT]), physical function (incremental shuttle walk distance [ISWD], quadriceps force), and C-reactive protein levels were assessed before and after treatment, and the corresponding data were analyzed in conjunction with clinical data. The adverse events of PR were also investigated.

Forty-two patients who met the study criteria were included in the analysis. After treatment, all LCQ item scores, total CAT score and sub-item scores related to respiratory symptoms, ISWD, quadriceps force, and C-reactive protein levels were found to have improved significantly. In the chronic cough with excessive sputum production (CCS) group, the proportions of responders who showed improvements in LCQ and CAT scores and ISWD greater than the corresponding minimal clinically important difference were significantly greater than those in the non-CCS group. No PR-related adverse events were reported.

Combined treatment with chemotherapy and PR may improve HRQoL and physical function, and supervised PR can be provided safely.

Bronchiectasis is considered a consequence of the neutrophilic inflammatory response to infection. Mycobacterial infections, mainly from the Mycobacterium avium complex and M. abscessus, have been inextricably linked to bronchiectasis development. The most important pathogen that infect patients with bronchiectasis is Pseudomonas aeruginosa, associated with an increased risk of death. Patients with bronchiectasis are often co-infected with P. aeruginosa and M. avium complex, and it was studied whether they interacted in immune cell cultures. Peripheral blood mononuclear cells from healthy volunteers were infected overnight with clinical isolates of mycobacteria, 18 h later co-infected with P. aeruginosa and Pseudomonas multiplication was quantified. Inoculated P. aeruginosa multiply faster when cells were previously infected in vitro with M. avium complex or M. tuberculosis, but not with M. kansasii or M. gordonae, mycobacteria not regularly isolated from patients with bronchiectasis. The interaction between mycobacteria and P. aeruginosa also takes place in the absence of cells, but to a lower degree. Growth of Staphylococcus aureus, less frequently co-isolated with mycobacteria, was not affected by previous infection with mycobacteria. Surprisingly, multiplication of P. aeruginosa in neutrophil cultures did not vary in the presence of mycobacteria. Nevertheless, co-infection of mycobacteria and P. aeruginosa induced the production of IL-1β, a mediator of neutrophilic inflammation. P. aeruginosa stimulation by mycobacteria provides evidence for explaining their common clinical association. Strategies to control mycobacteria may be useful to impair P. aeruginosa colonization.

Non-tuberculous mycobacteria (NTM) is a collective name given to a group of more than 190 species of Mycobacterium. The clinical presentation for most NTM infections is non-specific, often resulting in delayed diagnosis. Further complicating matters is that NTM organisms can be difficult to isolate. Medications used to treat NTM infection can be difficult for patients to tolerate, and prolonged courses of anti-mycobacterial therapy are often required for adequate suppression or eradication. Herein, we review different NTM syndromes, appropriate diagnostic tests, and treatment regimens.

Nontuberculous mycobacterial lung disease (NTM-LD) prevalence has been increasing over the recent decades. Numerous host factors are associated with NTM-LD development, including susceptible phenotypes such as ciliary defect and lung structural change, pulmonary clearance defect with poor clearance of secretions, and immune suppression. Specifically, regarding the susceptible host phenotypes without clear pathogenesis, a slender body, pectus excavatum, and postmenopausal female status are common. Also, decreased host immunity to NTM, especially T helper 1 cell responses is frequently observed. Even so, the underlying mechanisms remain unclear and relevant large-scale studies are lacking. Infections due to host genetics associated defects are mostly untreatable but rare in Asia, particularly Taiwan. Nevertheless, some risks for NTM-LD are controllable over disease progression. We suggest that clinicians first manage host factors and deal with the controllable characteristics of NTM-LD, followed by optimizing anti-NTM treatment. Further researches focusing on NTM-LD pathogenesis, especially the host–NTM interaction may advance understanding the nature of the disease and develop efficient therapeutic regimens.