Nontuberculous mycobacteria in bronchiectasis: prevalence and patient characteristics

Efficacy of an oscillating positive expiratory pressure device in patients with Mycobacterium avium complex pulmonary disease

Patients with Mycobacterium avium complex pulmonary disease (MAC-PD) often suffer from chronic symptoms such as sputum production, which reduces quality of life. Oscillatory positive expiratory pressure (OPEP) devices are used in physiotherapy to promote the clearance of respiratory secretions. We report two cases of improved lung function and improved scores on the Leicester Cough Questionnaire (LCQ) and the Breathlessness, Cough and Sputum Scale (BCSS) after the use of OPEP in patients with MAC-PD where treatment with guideline-based therapy, including amikacin liposome inhalation suspension, had proved ineffective for symptoms. Use of OPEP might maximize the efficacy of therapy and thereby improves outcomes in patients with MAC-PD. It is important to use both guideline-based therapy and OPEP, especially in patients whose health-related quality of life is affected by sputum symptoms. Further prospective studies are warranted to assess the benefit of adding OPEP to guidelines concerning therapy for patients with MAC-PD and sputum symptoms.

Is there a role for lung or bronchial biopsies for the diagnosis of mycobacterial pulmonary disease in patients with bronchiectasis?

Background

Workup of bronchiectasis patients mandates microbiological characterization often being sought via Bronchoscopy. However, whether to perform bronchial or lung biopsies, is unknown, especially for the diagnosis of NTM pulmonary disease. We aimed to assess the current practice and yield of the different bronchoscopic procedures in this setting.

Methods

Data from an adult cohort with bronchiectasis referred for bronchoscopy for microbiologic sampling was reviewed, including demographics, etiology, imaging and results of the different bronchoscopic procedures performed.

Results

127 subjects were analyzed (mean age 61, 56% female). BAL culture was positive in 44%. Frequent pathogens were Hemophilus Influenza (20%), pseudomonas aeruginosa (8%) and Staphylococcus aureus (7%). NTM and tuberculosis were found in 6% and 1.5% respectively. BAL cytology was sent in 125 procedures, EBB was performed in 51 patients (40%) and TBLB in 38 patients (30%). BAL cytology and both EBB and TBB (including tissue cultures) had no benefit over BAL with respect to microbiological diagnosis, including identification of mycobacterial disease.

Conclusions

In adult subjects with Non-CF bronchiectasis requiring bronchoscopy for microbiological characterization, BAL cytology and lung tissue biopsies were frequently performed but were of minimal additional benefit over BAL culture (including for mycobacterial pulmonary disease), and are most likely futile.

[Bronchiectasis not due to cystic fibrosis]

Bronchiectasis is a clinical-radiological condition composed of irreversible bronchial dilation due to inflammation and infection of the airways, which causes respiratory symptoms, usually productive cough and infectious exacerbations. Bronchiectasis can have multiple causes, both pulmonary and extrapulmonary, and its clinical presentation is very heterogenous. Its prevalence is unknown, although up to 35-50% of severe COPD and 25% of severe asthma present them, so their underdiagnosis is evident. Chronic bacterial bronchial infection is common, and Pseudomonas aeruginosa is the pathogen that has been found to imply a worse prognosis. Treatment of bronchiectasis has three fundamental characteristics: it must be multidisciplinary (involvement of several specialties), pyramidal (from primary care to the most specialized units) and multidimensional (management of all aspects that make up the disease).

Successful management of Mycobacterium abscessus pneumonia in a 53-day-old immunocompetent infant

Pulmonary infection due to Mycobacterium abscessus complex (MABC) usually occurs in children with underlying risk factors including cystic fibrosis (CF), chronic lung disease, and immunocompromised status, but rarely in immunocompetent children without underlying lung disease, especially in infants. We present a case of MABC pulmonary disease (MABC-PD) in an otherwise healthy 53-day-old male infant with one week of cough and respiratory distress. Computed tomography showed multiple masses across both lungs. Isolated mycobacteria from his bronchoalveolar lavage fluid were identified as MABC. We describe our complete evaluation, including immunodeficiency evaluation incorporating whole exome sequencing and our therapeutic process given complicated susceptibility pattern of the M. abscessus isolate, and review literature for MABC-PD in immunocompetent children. The infant was successfully treated through prolonged treatment with parenteral Amikacin, Cefoxitin, Linezolid, and Clarithromycin, combined with inhaled Amikacin.

Basic, translational and clinical aspects of bronchiectasis in adults

Bronchiectasis is a common progressive respiratory disease with recognisable radiological abnormalities and a clinical syndrome of cough, sputum production and recurrent respiratory infections. Inflammatory cell infiltration into the lung, in particular neutrophils, is central to the pathophysiology of bronchiectasis. Herein we explore the roles and relationships between infection, inflammation and mucociliary clearance dysfunction in the establishment and progression of bronchiectasis. Microbial and host-mediated damage are important processes underpinning bronchiectasis and the relative contribution of proteases, cytokines and inflammatory mediators to the propagation of inflammation is presented. We also discuss the emerging concept of inflammatory endotypes, defined by the presence of neutrophilic and eosinophilic inflammation, and explore the role of inflammation as a treatable trait. Current treatment for bronchiectasis focuses on treatment of underlying causes, enhancing mucociliary clearance, controlling infection and preventing and treating complications. Data on airway clearance approaches via exercise and mucoactive drugs, pharmacotherapy with macrolides to decrease exacerbations and the usefulness of inhaled antibiotics and bronchodilators are discussed, finishing with a look to the future where new therapies targeting host-mediated immune dysfunction hold promise.

The Airway Microbiome-IL-17 Axis: a Critical Regulator of Chronic Inflammatory Disease

The respiratory tract is home to a diverse microbial community whose influence on local and systemic immune responses is only beginning to be appreciated. Increasing reports have linked changes in this microbiome to a range of pulmonary and extrapulmonary disorders, including asthma, chronic obstructive pulmonary disease and rheumatoid arthritis. Central to many of these findings is the role of IL-17-type immunity as an important driver of inflammation. Despite the crucial role played by IL-17-mediated immune responses in protection against infection, overt Th17 cell responses have been implicated in the pathogenesis of several chronic inflammatory diseases. However, our knowledge of the influence of bacteria that commonly colonise the respiratory tract on IL-17-driven inflammatory responses remains sparse. In this article, we review the current knowledge on the role of specific members of the airway microbiota in the modulation of IL-17-type immunity and discuss how this line of research may support the testing of susceptible individuals and targeting of inflammation at its earliest stages in the hope of preventing the development of chronic disease.

Mechanisms by Which Liposomes Improve Inhaled Drug Delivery for Alveolar Diseases

Diseases of the pulmonary alveolus, such as pulmonary fibrosis, are leading causes of morbidity and mortality, but exceedingly few drugs are developed for them. A major reason for this gap is that after inhalation, drugs are quickly whisked away from alveoli due to their high perfusion. To solve this problem, the mechanisms by which nano-scale drug carriers dramatically improve lung pharmacokinetics using an inhalable liposome formulation containing nintedanib, an antifibrotic for pulmonary fibrosis, are studied. Direct instillation of liposomes in murine lung increases nintedanib's total lung delivery over time by 8000-fold and lung half life by tenfold, compared to oral nintedanib. Counterintuitively, it is shown that pulmonary surfactant neither lyses nor aggregates the liposomes. Instead, each lung compartment (alveolar fluid, alveolar leukocytes, and parenchyma) elutes liposomes over 24 h, likely serving as "drug depots." After deposition in the surfactant layer, liposomes are transferred over 3-6 h to alveolar leukocytes (which take up a surprisingly minor 1-5% of total lung dose instilled) in a nonsaturable fashion. Further, all cell layers of the lung parenchyma take up liposomes. These and other mechanisms elucidated here should guide engineering of future inhaled nanomedicine for alveolar diseases.

Insights into Personalised Medicine in Bronchiectasis

Bronchiectasis is a heterogenous disease with multiple aetiologies resulting in inflammation and dilatation of the airways with associated mucus production and chronic respiratory infection. The condition is being recognised ever more frequently as the availability of computed tomography increases. It is associated with significant morbidity and healthcare-related costs. With new understanding of the disease process, varying endotypes, identification of underlying causes and treatable traits, the management of bronchiectasis can be increasingly personalised.

Non-tuberculous mycobacterial infections in geriatric patients-A neglected and emerging problem

The diseases caused by Non-tuberculous mycobacteria (NTM) has increased steadily in the last two decades. Increase in incidence of NTM infections are being reported in elderly people as they are more susceptible and often experiencing high morbidity. There is prediction that NTM infections will further rise because of expected increase in elderly population by 2050. Given the importance of NTM infection in the elderly, the interest in studying NTM characteristics in the aged population is increasing. In this review, we summarize the characteristics of NTM infection among elderly patients. We focus on epidemiology, clinical presentation, and treatment options of NTM in this age group. We highlight the differences in the diagnosis and treatment between rapid and slow growing mycobacterial infections. The current recommendations for treatment of NTM have been discussed. Finally, we have reviewed the prognosis of NTM disease in elderly patients.

Non-Tuberculous Mycobacteria and Aspergillus Lung Co-Infection: Systematic Review

Non-tuberculous mycobacteria (NTM) and Aspergillus pulmonary co-infection occurs in patients with underlying lung disease and is rarely reported. We conducted a systematic search of NTM and Aspergillus pulmonary co-infection in PubMed, EMBASE, and Cochrane Library to identify cases published from 1977 to May 2022. We included 507 articles comprising 1538 cases (only 817 patients with partial relevant clinical data). Of these, 54.3% of patients were men, with a mean age of 57.7 years. Chronic obstructive pulmonary disease (21.1%), previous diagnosis of tuberculosis (18%), and asthma (11.1%) were the most common chronic lung diseases, and corticosteroids were used in 36.8% of patients. The most frequent symptoms were cough (68.2%), dyspnea (59.1%), and hemoptysis (34.1%). The most common radiological findings were bronchiectasis (52.3%) and cavitation (40.8%). NTM and Aspergillus were treated simultaneously in 47.3% of cases, whereas NTM-targeted therapy only was performed in 23.4% and Aspergillus only in 1.6%. The remaining 27.7% did not receive any treatment and were considered to be colonized. The global mortality rate was 43% (159/370). There was an increased prevalence of NTM and pulmonary aspergillosis among patients with underlying chronic lung diseases, which led to severe pulmonary affection with a poor global prognosis.

Global prevalence of non-tuberculous mycobacteria in adults with non-cystic fibrosis bronchiectasis 2006-2021: a systematic review and meta-analysis

OBJECTIVE

To accurately estimate the global prevalence of non-tuberculous mycobacteria (NTM) in adults with non-cystic fibrosis (non-CF) bronchiectasis and to determine the proportion of NTM species and subspecies in clinical patients from 2006 to 2021.

DESIGN

Systematic review and meta-analysis using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

DATA SOURCES

Medline, Embase, Cochrane Library and Web of Science were searched for articles published between 2006 and 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included all the prospective or retrospective studies without language restrictions and all patients were adults (≥18 years of age) with non-CF bronchiectasis. The studies estimated the effect size of the prevalence of NTM with a sample size ≥40, and patients were registered in and after 2006.

DATA EXTRACTION AND SYNTHESIS

Two reviewers screened the titles, abstracts and full texts independently. Relevant information was extracted and curated into tables. Risk of bias was evaluated following the Cochrane Collaboration's tool. Meta-analysis was performed with software R Statistics V.3.6.3 using random effect model with 95% CI. I² index and Q statistics were calculated to assess the heterogeneity, and mixed-effects meta-regression analyses were performed to identify the sources of heterogeneity. The proportions of NTM subspecies were examined using Shapiro-Wilk normality test in R.

RESULTS

Of all the 2014 studies yielded, 24 met the inclusion criteria. Of these, 14 were identified to be randomised controlled studies and included for an accurate estimation. The global prevalence of NTM in adults with non-CF bronchiectasis from 2006 to 2021 was estimated to be approximately 10%, with great variations primarily due to geographical location. Mycobacterium avium complex was the most common subspecies, followed by Mycobacterium simiae and Mycobacterium gordonae.

CONCLUSIONS

The prevalence of NTM in adults with non-CF bronchiectasis has been on the rise and the most common subspecies changed greatly in recent years. More cohort studies should be done in many countries and regions for future estimates.

PROSPERO REGISTRATION NUMBER

CRD42020168473.

Non-tuberculous mycobacteria pulmonary disease: A review of trends, risk factors, diagnosis and management

Non-tuberculous mycobacteria (NTM) reports have been on the rise globally, with increasing incidence and prevalence accompanied by poor outcomes. The rise has been attributed to an ageing population with increasing comorbid illnesses, and improved laboratory techniques in diagnosing the disease. However, despite the increase, some parts of the world still lack data, especially sub-Saharan African countries. The lack of data in our setting is difficult to explain, as we have a significant burden of NTM risk factors (i.e. HIV, tuberculosis and bronchiectasis). This review therefore serves as a reminder and a challenge to start searching, and reporting on our experiences. The review will highlight the rising incidence, important risk factors, diagnosis and management of NTM pulmonary disease.

Risk Factors for the Development of Nontuberculous Mycobacteria Pulmonary Disease during Long-Term Follow-Up after Lung Cancer Surgery

The aim of this study is to determine the cumulative incidence of, and the risk factors for, the development of nontuberculous mycobacteria pulmonary disease (NTM-PD) following lung cancer surgery. We retrospectively analyzed patients with non-small cell lung cancer who underwent surgical resection between 2010 and 2016. Patients who met all the diagnostic criteria in the NTM guidelines were defined as having NTM-PD. Additionally, we classified participants as NTM-positive when NTM were cultured in respiratory specimens, regardless of the diagnostic criteria. We followed 6503 patients for a median of 4.89 years, and NTM-PD and NTM-positive diagnoses occurred in 59 and 156 patients, respectively. The cumulative incidence rates of NTM-PD and NTM-positive were 2.8% and 5.9% at 10 years, respectively. Mycobacterium avium complex was the most commonly identified pathogen, and half of the NTM-PD patients had cavitary lesions. Several host-related factors (age > 65 years, body mass index ≤ 18.5 kg/m2, interstitial lung disease, bronchiectasis, and bronchiolitis) and treatment-related factors (postoperative pulmonary complications and neoadjuvant/adjuvant treatments) were identified as risk factors for developing NTM-PD and/or being NTM-positive after lung cancer surgery. The incidences of NTM-PD and NTM-positive diagnoses after lung cancer surgery were not low, and half of the NTM-PD patients had cavitary lesions, which are known to progress rapidly and often require treatment. Therefore, it is necessary to raise awareness of NTM-PD development after lung cancer surgery.

Mycobacterium avium-intracellulare complex promote release of pro-inflammatory enzymes matrix metalloproteinases by inducing neutrophil extracellular trap formation

The prevalence of and mortality from non-tuberculous mycobacteria (NTM) infections have been steadily increasing worldwide. Most NTM infections are caused by Mycobacterium avium-intracellulare complex (MAC). MAC can escape from killing by neutrophils, which are professional phagocytes. However, the involvement of neutrophils in the pathogenesis of MAC infection is poorly understood. The present study assessed the roles of neutrophil extracellular trap (NET) formation in neutrophil defense mechanisms against infection with MAC strains, including M. avium isolated from patients with severe or mild lung tissue destruction. Although all MAC induced NET formation, non-pathogenic mycobacteria (M. gordonae and M. smegmatis) slightly but not significantly induced NET formation. Peptidylarginine deiminase 4 (PAD4) inhibitor reduced MAC-induced NET formation but did not affect MAC escape from neutrophils. PAD4 inhibition attenuated the MAC-induced matrix metalloproteinase (MMP)-8 and 9 release to the levels of MMPs from non-pathogenic mycobacteria. MAC also induced interleukin (IL)-8 release by neutrophils, a process independent of MAC-induced NET formation. Taken together, these findings suggest that MAC induce NET formation, IL-8 release and NETs-dependent release of MMP-8 and -9 from neutrophils, leading to neutrophil accumulation and further inflammation, thereby enhancing the progression of infection in the lungs.

Management of Mycobacterium avium complex and Mycobacterium abscessus pulmonary disease: therapeutic advances and emerging treatments

Nontuberculous mycobacterial pulmonary disease (NTM-PD) remains a challenging condition to diagnose and treat effectively. Treatment of NTM-PD is prolonged, frequently associated with adverse effects and has variable success. In this review, we consider the factors influencing clinicians when treating NTM-PD and discuss outcomes from key studies on the pharmacological management of Mycobacterium avium complex pulmonary disease and M. abscessus pulmonary disease. We highlight issues relating to treatment-related toxicity and provide an overview of repurposed and emerging therapies for NTM-PD.

Characterisation of the post-tuberculous phenotype of bronchiectasis: A real-world observational study

OBJECTIVE

Bronchiectasis is a heterogeneous disease with distinct phenotypes. The post-tuberculosis (post-TB) bronchiectasis phenotype is prevalent in many countries but is under-studied. Our aim was to identify distinct phenotypic characteristics of post-TB bronchiectasis.

METHODS

We recruited adults admitted between Jan 2010-Oct 2017 at Changi General Hospital, Singapore for bronchiectasis exacerbation. We collected demographics, symptoms, lung function, microbiology and FACED scores. Participants were followed-up until the next hospitalized exacerbation or end of study, whichever was sooner. Participants diagnosed by their attending respiratory specialist to have post-TB bronchiectasis were compared to those with bronchiectasis from other aetiologies.

RESULTS

148 participants were included with mean±standard deviation age 63 ± 9 years; 46 (31.1%) had post-TB bronchiectasis and 102 (68.9%) other aetiologies. Compared to other aetiologies, participants with post-TB bronchiectasis had significantly lower body mass index (BMI), more frequent presentation with haemoptysis, lower forced expiratory volume in one second (FEV1), more frequent isolation of nontuberculous mycobacteria (NTM), and higher FACED scores indicating greater disease severity. Over a median follow-up of 21 months, post-TB bronchiectasis was associated with shorter time to next hospitalized exacerbation (49 vs 76 months, Log-Rank p = .01).

CONCLUSION

Post-TB bronchiectasis is a distinct entity with higher rates of haemoptysis and NTM isolation, more frequent exacerbations, and greater disease severity.

Clinical characteristics of patients with bronchiectasis with nontuberculous mycobacterial disease in Mainland China: a single center cross-sectional study

BACKGROUND

The diagnosis and treatment of patients with bronchiectasis and nontuberculous mycobacterium (NTM) pulmonary disease are challenging issues and the treatment is also prolonged and depends on the species. There is limited information on patients with bronchiectasis and NTM pulmonary disease in Mainland China.

METHODS

This cross-sectional study was conducted at the China-Japan Friendship Hospital, Beijing, China. Those adult patients who met the diagnostic criteria for bronchiectasis and obtained a culture result of mycobacteria from lower respiratory tract specimens or lung tissue were included in this study. A logistic regression model was used to identify the related factors in patients with NTM pulmonary disease.

RESULTS

A total of 202 patients with bronchiectasis from 19 cities, 155 without and 47 (23.3%) with NTM pulmonary disease, were included. In all the 47 patients with NTM pulmonary disease, Mycobacterium avium complex was the most common species (66.0%), and 72.3% of them were initiated on standard anti-NTM treatment within 3 months after the diagnosis of NTM pulmonary disease. A larger proportion of patients with NTM pulmonary disease had acute exacerbations of ≥ 3 times within 1 year and were diagnosed bronchiectasis ≥ 50 years among patients with NTM pulmonary disease. The HRCT chest images revealed higher proportions of nodular shadow (100% vs. 35.3%), tree-in-bud sign (97.9% vs. 29.0%), cavities (29.8% vs. 5.8%), and airway dilation of the right middle lobe or the left lingular lobe (63.8% vs. 23.9%) in patients with NTM pulmonary disease than in those without NTM pulmonary disease (all P values = 0.001). The multivariable logistic regression model indicated that three and more abnormal features (OR 33.8; 95% CI 11.1-102.8) and main lesions of bronchial expansion in the middle or lingual lobe (OR 6.4; 95% CI 2.4-16.6) in HRCT chest images were independently associated with NTM pulmonary disease (P values = 0.001).

CONCLUSION

In a single center of Mainland China, > 23% of patients with bronchiectasis had NTM pulmonary disease, and most patients were started on standard treatment within 3 months after the diagnosis of NTM pulmonary disease. These findings suggest that patients with bronchiectasis should be thoroughly examined for the presence of NTM pulmonary disease.

TRIAL REGISTRATION

NCT03594032.

Prevalence and Clinical Characteristics of Nontuberculous Mycobacteria in Patients with Bronchiectasis: A Systematic Review and Meta-Analysis

BACKGROUND

Although international bronchiectasis guidelines recommended screening of nontuberculous mycobacteria (NTM) both at initial evaluation and prior to administration of macrolide treatment, data regarding NTM in bronchiectasis remain elusive.

OBJECTIVE

To establish the prevalence, species, and clinical features of NTM in adults with bronchiectasis.

METHODS

We searched PubMed, Embase, and Web of Science for studies published before April 2020 reporting the prevalence of NTM in adults with bronchiectasis. We only included studies with bronchiectasis confirmed by computed tomography and NTM identified by mycobacteria culture or molecular methods. Random-effects meta-analysis was employed.

RESULTS

Of the 2,229 citations identified, 21 studies, including 12,454 bronchiectasis patients were included in the final meta-analysis. The overall pooled prevalence of NTM isolation and pulmonary NTM disease were 7.7% (5.0%-11.7%) (n/N = 2,677/12,454) and 4.1% (1.4%-11.4%) (n/N = 30/559), respectively, with significant heterogeneity (I2 = 97.7%, p < 0.001 and I2 = 79.9%, p = 0.007; respectively). The prevalence of NTM isolation varied significantly among different geographical regions with the highest isolation at 50.0% (47.3%-52.7%) reported in the United States. Mycobacterium avium complex and Mycobacterium abscessus complex accounted for 66 and 16.6% of all species, respectively. Some clinical and radiological differences were noted between patients with and without the presence of NTM isolation although the results are inconsistent.

CONCLUSIONS

Heterogeneity in prevalence estimates of NTM isolation indicated that both local surveys to inform development of clinical services tailored to patients with bronchiectasis and population-based studies are needed. The clinical features associated with NTM in bronchiectasis and their incremental utility in studying the association is unknown and merits further investigation.

Pathophysiology of Bronchiectasis

Bronchiectasis is a complex, heterogeneous disorder defined by both a radiological abnormality of permanent bronchial dilatation and a clinical syndrome. There are multiple underlying causes including severe infections, mycobacterial disease, autoimmune conditions, hypersensitivity disorders, and genetic conditions. The pathophysiology of disease is understood in terms of interdependent concepts of chronic infection, inflammation, impaired mucociliary clearance, and structural lung damage. Neutrophilic inflammation is characteristic of the disease, with elevated levels of harmful proteases such as neutrophil elastase associated with worse outcomes. Recent data show that neutrophil extracellular trap formation may be the key mechanism leading to protease release and severe bronchiectasis. Despite the dominant of neutrophilic disease, eosinophilic subtypes are recognized and may require specific treatments. Neutrophilic inflammation is associated with elevated bacterial loads and chronic infection with organisms such as Pseudomonas aeruginosa. Loss of diversity of the normal lung microbiota and dominance of proteobacteria such as Pseudomonas and Haemophilus are features of severe bronchiectasis and link to poor outcomes. Ciliary dysfunction is also a key feature, exemplified by the rare genetic syndrome of primary ciliary dyskinesia. Mucus symptoms arise through goblet cell hyperplasia and metaplasia and reduced ciliary function through dyskinesia and loss of ciliated cells. The contribution of chronic inflammation, infection, and mucus obstruction leads to progressive structural lung damage. The heterogeneity of the disease is the most challenging aspect of management. An understanding of the pathophysiology of disease and their biomarkers can help to guide personalized medicine approaches utilizing the concept of "treatable traits."

Posttreatment Lymphopenia Is Associated With an Increased Risk of Redeveloping Nontuberculous Lung Disease in Patients With Mycobacterium avium Complex Lung Disease

BACKGROUND

Lymphopenia has been reported as a risk factor for poor prognosis in various infectious diseases, including Mycobacterium avium complex lung disease (MAC-LD), and recurrence in several infectious diseases. However, the association between lymphopenia and the risk of redeveloping nontuberculous lung disease (NTM-LD) after completed treatment for MAC-LD is unknown.

METHODS

We performed a retrospective cohort study with 147 patients with MAC-LD who successfully completed guideline-based therapy. Lymphopenia was defined as an absolute lymphocyte count (ALC) <1000 cells/μL based on commonly accepted reference values.

RESULTS

During the median follow-up period of 41.9 months after treatment completion, 59 (40.1%) patients redeveloped NTM-LD. Patients with NTM-LD redevelopment had significantly lower posttreatment ALCs (median, 1260 vs 1420 cells/μL) than those without, and the univariate Cox proportional hazard analysis identified posttreatment ALC as a predictive factor for redevelopment (hazard ratio, .94 [95% confidence interval, .89-.99] for every increase of 100 cells/μL; P = .04). In the multivariate analysis, posttreatment ALC and the extent of bronchiectasis were independently associated with NTM-LD redevelopment. The cumulative rate of NTM-LD redevelopment was significantly higher in patients with posttreatment lymphopenia than in those without (P = .008).

CONCLUSIONS

Posttreatment lymphopenia could predict an increased risk of NTM-LD redevelopment after completed treatment for MAC-LD.

Prognosis of nontuberculous mycobacterial pulmonary disease according to the method of microbiologic diagnosis

Microbiological criteria for nontuberculous mycobacterial pulmonary disease (NTM-PD) require cultures from two separate sputum or one non-sputum specimen. However, there is limited data on the progression of NTM-PD following non-sputum culture-based diagnosis. We compared the disease progression of NTM-PD diagnosed with non-sputum vs sputum cultures. We included 833 patients and divided them into sputum NTM isolation (n = 123), sputum NTM-PD (n = 558), and non-sputum NTM-PD groups (n = 152). Disease progression, defined as radiographic aggravation and therapy initiation, was compared between groups. The median observation time was 60.5 months (interquartile range, 31.4-96.0). The non-sputum NTM-PD group showed longer treatment-free survival (log-rank test; p = 0.009) and lower risk of treatment (adjusted hazard ratio [aHR] of sputum NTM-PD group, 1.36; 95% confidence interval (CI), 1.01-1.84) than the sputum NTM-PD group. The non-sputum NTM-PD group showed longer radiographic aggravation-free survival (Log-rank test; p = 0.015) and lower risk of radiographic aggravation (aHR of sputum NTM-PD group, 1.52; 95% CI, 1.06-2.19) than the sputum NTM-PD group. NTM-PD diagnosed using methods other than sputum culture showed a low risk of disease progression and progressed slower than NTM-PD diagnosed from a sputum culture. NTM-PD diagnosed using methods other than sputum culture may be a mild disease, not equivalent to NTM-PD diagnosed from sputum culture.

Chronic Pulmonary Aspergillosis Following Nontuberculous Mycobacterial Infections: An Emerging Disease

Chronic pulmonary aspergillosis (CPA) following nontuberculous mycobacterial (NTM) lung disease is being increasingly recognized, especially in countries where tuberculosis is not endemic, with an incidence rate of 3.9–16.7%. NTM lung disease has been identified as a predictor of mortality in CPA patients. The major risk factors for NTM-associated CPA include fibrocavitary NTM lung disease, the presence of pulmonary emphysema, and high-dose corticosteroid use. The onset of CPA is 1.5–7 years following the diagnosis of NTM lung disease. The diagnosis can be made using standard criteria; however, serological diagnosis using Aspergillus precipitin has demonstrated a higher sensitivity and specificity when compared with fungal culture from respiratory specimens. Treatment is challenging since rifampicin and oral triazoles should not be used concomitantly. The prognosis is poor, and the factors associated with worse prognosis are corticosteroid use and high C-reactive protein level.

Radiologic Characteristics of Non-tuberculous Mycobacteria Infection in Patients with Bronchiectasis

INTRODUCTION

Non-tuberculous mycobacteria pulmonary disease (NTM-pd) commonly complicates bronchiectasis. However, clinical and radiological features of NTM-pd and bronchiectasis are very similar. We aimed to develop a radiologic prediction tool for bronchiectasis to identify NTM-pd.

METHODS

We reviewed clinical, laboratory and radiological data in patients with bronchiectasis. Radiologic features on CT scans and the individual components of the Bhalla scoring system were compared between people with and without NTM-pd. Logistic regression and receiver-operating curve (ROC) analysis were performed to predict NTM-pd.

RESULTS

People with NTM-pd had more pulmonary segments with bronchiectasis (13 ± 5 vs. 11 ± 5, p = 0.03), presence of mucus plugging (47% vs. 19%, p < 0.0001) and tree in bud infiltrates (53% vs. 28%, p = 0.004). The total modified- Bhalla score was worse among people with NTM-pd (median [IQR] 11[9,13] vs. 9[8,12], p = 0.03). Logistic regression identified the number of pulmonary segments involved, presence of bullae, consolidations, and a total score of 10 or more to be independently associated with presence of NTM-pd. ROC analysis with radiographic variables only identified an AUC of 0.706 (95% CI 0.644-0.762). When people with chronic Pseudomonas infection were excluded from the ROC analysis, prediction for NTM was improved: AUC = 0.87 (95% CI 0.796-0.945).

DISCUSSION AND CONCLUSIONS

Radiological features together with advanced age and female gender may predict NTM-pd among people with bronchiectasis. Infection with Pseudomonas aeruginosa may resemble NTM radiographically, and this prediction rule may better differentiate people with and without NTM-pd when Pseudomonas infection is not present.

Pulmonary non-tuberculous mycobacterial infections: current state and future management

Currently, there is a trend of increasing incidence in pulmonary non-tuberculous mycobacterial infections (PNTM) together with a decrease in tuberculosis (TB) incidence, particularly in developed countries. The prevalence of PNTM in underdeveloped and developing countries remains unclear as there is still a lack of detection methods that could clearly diagnose PNTM applicable in these low-resource settings. Since non-tuberculous mycobacteria (NTM) are environmental pathogens, the vicinity favouring host-pathogen interactions is known as important predisposing factor for PNTM. The ongoing changes in world population, as well as socio-political and economic factors, are linked to the rise in the incidence of PNTM. Development is an important factor for the improvement of population well-being, but it has also been linked, in general, to detrimental environmental consequences, including the rise of emergent (usually neglected) infectious diseases, such as PNTM. The rise of neglected PNTM infections requires the expansion of the current efforts on the development of diagnostics, therapies and vaccines for mycobacterial diseases, which at present, are mainly focused on TB. This review discuss the current situation of PNTM and its predisposing factors, as well as the efforts and challenges for their control.

Post tuberculosis treatment infectious complications

Following greater attention and follow-up of patients with treated pulmonary tuberculosis (TB), it has emerged that infections are more likely to occur in this cohort of patients. This comes as no surprise, as pulmonary TB is a destructive process that leads to cicatrization, alteration of parenchyma, bronchiectasis, and scarring of the lung, with reduction of lung volumes and an impact on pulmonary function. In addition to relapse and re-infection with TB, other pathogens are increasingly recognized in post-TB patients. This paper serves as a summary and guide on how to approach the post-TB patient with new signs and symptoms of pulmonary infection in order to ensure optimal management and rehabilitation.

Diagnosis of non-tuberculous mycobacterial pulmonary disease (NTM-PD): modern challenges

Non-tuberculous mycobacterial pulmonary disease is growing in incidence and prevalence. However, it is frequently overlooked as a differential diagnosis by both clinicians and radiologists alike due to its non-specific clinical features, wide spectrum of radiological findings and difficulty in isolating the causative organism. The aim of this article is to illustrate the spectrum and follow-up of the radiological findings of non-tuberculous mycobacterial pulmonary disease and the challenges involved in making a diagnosis.

The biology of pulmonary exacerbations in bronchiectasis

Bronchiectasis is a heterogeneous chronic disease. Heterogeneity characterises bronchiectasis not only in the stable state but also during exacerbations, despite evidence on clinical and biological aspects of bronchiectasis, exacerbations still remain poorly understood.Although the scientific community recognises that bacterial infection is a cornerstone in the development of bronchiectasis, there is a lack of data regarding other trigger factors for exacerbations. In addition, a huge amount of data suggest a primary role of neutrophils in the stable state and exacerbation of bronchiectasis, but the inflammatory reaction involves many other additional pathways. Cole's vicious cycle hypothesis illustrates how airway dysfunction, airway inflammation, infection and structural damage are linked. The introduction of the concept of a "vicious vortex" stresses the complexity of the relationships between the components of the cycle. In this model of disease, exacerbations work as a catalyst, accelerating the progression of disease. The roles of microbiology and inflammation need to be considered as closely linked and will need to be investigated in different ways to collect samples. Clinical and translational research is of paramount importance to achieve a better comprehension of the pathophysiology of bronchiectasis, microbiology and inflammation both in the stable state and during exacerbations.

Insufficient serum L-ficolin is associated with disease presence and extent of pulmonary Mycobacterium avium complex disease

BACKGROUND

The incidence of infectious disease caused by nontuberculous mycobacteria is increasing worldwide. Pulmonary Mycobacterium avium complex (MAC) disease is difficult to treat with chemotherapy, and its mechanism of infection, infection route, disease onset, and severity remain unknown. Ficolins are oligomeric defense lectins. L-ficolin plays an important role in innate immunity. This study's aim was to identify L-ficolin's role in patients with pulmonary MAC disease.

METHODS

Between April 2011 and September 2017, 61 Japanese patients with pulmonary MAC disease were seen at our hospital. A control group, comprising 30 healthy individuals, without respiratory disease were enrolled in our study. The relationship between serum L-ficolin levels and disease severity was assessed, and L-ficolin's antibacterial role was examined.

RESULTS

Serum L-ficolin levels were significantly lower in patients with pulmonary MAC disease than in healthy subjects (1.69 ± 1.27 μg/ml vs. 3.96 ± 1.42 μg/ml; p < 0.001). The cut-off value, based on receiver operating characteristic (ROC) analysis results, was 2.48 μg/ml (area under the curve (AUC) 0.90, sensitivity and specificity 83.6 and 86.7%, respectively). Serum L-ficolin levels were significantly lower in the patients with nodular bronchiectatic type disease compared with the patients with fibrocavitary type disease and were lower in the high-resolution computed tomography high-scoring group compared with low-scoring group. An in vitro analysis showed that purified recombinant L-ficolin bound to M. avium and its major cell wall component, lipoarabinomannan, in a concentration-dependent manner. In addition, recombinant L-ficolin suppressed M. avium growth in a concentration-dependent manner.

CONCLUSIONS

Insufficient serum L-ficolin is associated with disease progression in pulmonary MAC disease, and the level of serum L-ficolin is a possible biomarker.

TRIAL REGISTRATION

This study is registered with UMIN ( UMIN000022392 ).

Non-tuberculous mycobacterial pulmonary disease

Nontuberculous mycobacterial pulmonary disease (NTM-PD) is a challenging infection which is becoming increasingly prevalent, particularly in the elderly, for reasons which are unknown. While underlying lung disease is a well-established risk factor for NTM-PD, it may also occur in apparently healthy individuals. No single common genetic or immunological defect has been identified in this group, and it is likely that multiple pathways contribute towards host susceptibility to NTM-PD which further interact with environmental and microbiological factors leading to the development of disease.The diagnosis of NTM-PD relies on the integration of clinical, radiological and microbiological results. The clinical course of NTM-PD is heterogeneous, with some patients remaining stable without the need for treatment and others developing refractory disease associated with considerable mortality and morbidity. Treatment regimens are based on the identity of the isolated species, drug sensitivity testing (for some agents) and the severity of disease. Multiple antibiotics are typically required for prolonged periods of time and treatment is frequently poorly tolerated. Surgery may be beneficial in selected cases. In some circumstances cure may not be attainable and there is a pressing need for better regimens to treat refractory and drug-resistant NTM-PD.This review summarises current knowledge on the epidemiology, aetiology and diagnosis of NTM-PD and discusses the treatment of two of the most clinically significant species, the M. avium and M. abscessus complexes, with a focus on refractory disease and novel therapies.

Outcomes in Lung Transplant Recipients With Mycobacterium abscessus Infection: A 15-Year Experience From a Large Tertiary Care Center

BACKGROUND

Mycobacterium abscessus (M abscessus) infection is a serious complication post-lung transplant (LTx). We examined determinants of outcomes in LTx recipients infected with M abscessus.

METHODS

Electronic records of all patients who underwent LTx in a single transplant center between 2000 and 2015 were screened for isolation of M abscessus before or after LTx.

RESULTS

Twenty-six cases of M abscessus isolation were identified. Twenty-four had M abscessus isolation post-LTx. Two had M abscessus isolated from a surgical site, while the others were pulmonary isolates. Out of these 22 with pulmonary isolates, 12 had clinical disease. In 73% of patients, treatment had to be temporarily held or switched due to intolerance and toxicity. There was a statistically significant worsening in survival in those who developed clinical disease compared to matched controls. Among the 12 patients with clinical pulmonary disease, use of clofazimine was significantly associated with a favorable outcome. Six patients had M abscessus isolation pretransplant. Four developed M abscessus recurrence at a median of 2 months post-LTx. Two recurrences were surgical site infections, and 2 were pulmonary infections.

CONCLUSION

M abscessus infection is difficult to treat as tolerance to medications used is poor. M abscessus pneumonia is associated with worse survival post-LTx. Use of clofazimine is associated with 1-year infection-free survival.

Performance of RGM Medium for Isolation of Nontuberculous Mycobacteria from Respiratory Specimens from Non-Cystic Fibrosis Patients

A new selective medium for rapidly growing mycobacteria (RGM medium) was evaluated on respiratory specimens from non-cystic fibrosis patients and compared to the mycobacterial growth indicator tube (MGIT) system and Middlebrook 7H11 agar for the isolation of all nontuberculous mycobacteria (NTM). A total of 203 mucolyzed respiratory specimens collected from 163 patients were inoculated on RGM medium and incubated at both 30°C (RGM30) and 35°C (RGM35) over a 28-day period. N-Acetyl-l-cysteine-sodium hydroxide (NALC-NaOH)-decontaminated specimens were inoculated into MGIT and Middlebrook 7H11 agar and incubated at 35°C for 42 days. NTM were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) or gene sequencing. A total of 133 NTM isolates were recovered overall from 101 (49.8%) specimens collected from 85 (52.1%) patients by a combination of all culture methods. The sensitivity of RGM30 for the recovery of NTM was significantly higher than that of either the MGIT system (76.7% versus 59.4%; P = 0.01) or Middlebrook 7H11 agar (76.7% versus 47.4%; P = 0.0001) alone, but it was not significantly different from that of an acid-fast bacillus culture (AFC) which includes both MGIT and Middlebrook 7H11 agar (76.7% versus 63.9%; P = 0.0647). RGM35 had significantly lower sensitivity than the MGIT system (49.6% versus 59.4%; P = 0.0367) and AFC (49.6% versus 63.9%; P = 0.0023). RGM medium was highly effective at inhibiting the growth of nonmycobacterial organisms in the respiratory specimens, with breakthrough contamination rates of 5.4% and 4.4% for RGM30 and RGM35, respectively.

Epidemiology of pulmonary disease due to nontuberculous mycobacteria in Southern China, 2013-2016

Background

Pulmonary nontuberculous mycobacteria (NTM) disease is of increasing public health concern in China. Information is limited regarding risk factors associated with this disease in China. The objective of this study was to describe the epidemiology of pulmonary disease due to NTM in Southern China.

Methods

We retrospectively reviewed the medical records of pulmonary NTM patients registered in the Guangzhou Chest Hospital with positive mycobacterial cultures during 2013–2016. We described sex, age, residence, treatment history, laboratory examination results and comorbidities of pulmonary NTM patients.

Results

Among the 607 NTM cases, the most prevalent species were Mycobacterium avium complex (44.5%), Mycobacterium abscessus complex (40.5%), Mycobacterium kansasii (10.0%) and Mycobacterium fortuitum (2.8%). The male:female ratio was significantly lower among patients infected with rapidly growing mycobacteria (RGM) than among those with slowly growing mycobacteria (SGM). The risk of developing SGM disease significantly increased with advancing age. In addition, pulmonary RGM diseases were more common in migrant population than resident population. Notably, patients with pulmonary RGM diseases were significantly more likely to have bronchiectasis underlying noted than those with SGM diseases. No significant difference was observed in in vitro drug susceptibility among NTM species.

Conclusion

Our data illustrate that the M. avium complex is the most predominant causative agent of pulmonary NTM disease in Southern China. Female, migrant population, the presence of bronchiectasis are independent risk factors for pulmonary diseases due to RGM. In addition, the prevalence of SGM increases significantly with advancing age.

Increasing Non-tuberculous Mycobacteria Infections in Veterans With COPD and Association With Increased Risk of Mortality

Background: There are limited data on the epidemiology of Non-tuberculous mycobacteria (NTM) infections among patients with COPD, particularly in the veteran population. This study examined the prevalence, incidence, and mortality of pulmonary NTM infections among veterans with COPD population in the United States.

Methods: We analyzed nationwide data from Veterans Affairs Hospitals from 2001 to 2015. First, we determined the incidence and prevalence rates and geographic distribution of NTM infections among veterans with COPD and then we evaluated the association between NTM infections with mortality among veterans with COPD. Pulmonary NTM and COPD diagnosis were defined based on charting claims for each condition on ≥2 occasions and ≥30 days apart. COPD diagnoses had to precede diagnosis of NTM. Cox Proportional-Hazards Regression was performed to determine the dependency of survival time of COPD patients with NTM.

Results: The incidence and prevalence rates of NTM rose over the study period, with a sharp rise in incidence after 2012. The areas with the highest NTM period prevalence were Puerto Rico (370), followed by Florida (351) and District of Columbia (309) in 100,000 COPD population. Mortality registered for those patients with COPD Patients and NTM infection was 1.43 times higher compared to those that were uninfected.

Conclusions: NTM rates have been increasing in veterans with COPD since 2012. NTM infection is associated with increased risk of mortality. This highlights the importance of identifying preventable risk factors associated with NTM infections in subjects with COPD.

Impact of concomitant nontuberculous mycobacteria and Pseudomonas aeruginosa isolates in non-cystic fibrosis bronchiectasis

Purpose

Pseudomonas aeruginosa is associated with pulmonary function decline and high disease severity in non-cystic fibrosis (CF) bronchiectasis. The prevalence of nontuberculous mycobacteria (NTM) in non-CF bronchiectasis patients has increased recently. This study investigated the impact of NTM with or without P. aeruginosa isolates in non-CF bronchiectasis patients.

Patients and methods

Our retrospective study included 96 non-CF bronchiectasis patients from January 2005 to December 2014. We recorded the presentation, exacerbations, emergency department (ED) visits, hospitalization, serial pulmonary function, radiologic studies, and sputum culture results. All patients were followed up for at least 2 years.

Results

The 96 patients were divided into four groups: patients with concomitant negative NTM and P. aeruginosa isolates (n=41; group 1), patients with positive NTM isolates (n=20; group 2), patients with positive P. aeruginosa isolates (n=20; group 3), and patients with concomitant positive NTM and P. aeruginosa isolates (n=15; group 4). Compared with group 1 patients, patients in groups 2 and 3 showed a significant decline in forced expiratory volume in 1 second (FEV₁). They also had more frequent annual acute exacerbations (AE), ED visits, and hospitalization. Group 4 patients had the greatest FEV₁ and forced vital capacity (FVC) decline and the most frequent AE, ED visits, and hospitalization.

Conclusion

Concomitant NTM and P. aeruginosa isolates in non-CF bronchiectasis are associated with the greatest pulmonary function decline and the worst disease severity. This result suggested that early recognition and prompt treatment of concomitant NTM and P. aeruginosa isolates may improve the outcome in non-CF bronchiectasis patients.

Risk of Development of Resistance in Patients with Non-Cystic Fibrosis Bronchiectasis Treated with Inhaled Antibiotics

Purpose of Review

Bronchiectasis is a debilitating chronic lung disease characterised by recurrent bacterial infection and colonisation with significant associated morbidity and mortality. To date, there are few licenced treatments, and the mainstay of clinical management is prompt antibiotic therapy for exacerbations and regular airway clearance. Inhaled antibiotics are a potential long-term treatment for those with recurrent exacerbations, and represent an obvious advantage over other routes of administration as they achieve high concentrations at the site of infection whilst minimising systemic side effects. The main caveat to such treatment is the development of antimicrobial resistance due to altered selection pressures.

Recent Findings

Numerous studies of various inhaled antimicrobials have demonstrated favourable safety and efficacy profiles for bronchiectasis patients with chronic infection, which are supportive of their use in clinical practice.

Summary

There is no convincing evidence of treatment-emergent pathogens or pathogens developing resistance to the inhaled antibiotic therapy.

Pathogenesis, imaging and clinical characteristics of CF and non-CF bronchiectasis

Bronchiectasis is a common feature of severe inherited and acquired pulmonary disease conditions. Among inherited diseases, cystic fibrosis (CF) is the major disorder associated with bronchiectasis, while acquired conditions frequently featuring bronchiectasis include post-infective bronchiectasis and chronic obstructive pulmonary disease (COPD). Mechanistically, bronchiectasis is driven by a complex interplay of inflammation and infection with neutrophilic inflammation playing a predominant role. The clinical characterization and management of bronchiectasis should involve a precise diagnostic workup, tailored therapeutic strategies and pulmonary imaging that has become an essential tool for the diagnosis and follow-up of bronchiectasis. Prospective future studies are required to optimize the diagnostic and therapeutic management of bronchiectasis, particularly in heterogeneous non-CF bronchiectasis populations.

Geographic variation in the aetiology, epidemiology and microbiology of bronchiectasis

Bronchiectasis is a disease associated with chronic progressive and irreversible dilatation of the bronchi and is characterised by chronic infection and associated inflammation. The prevalence of bronchiectasis is age-related and there is some geographical variation in incidence, prevalence and clinical features. Most bronchiectasis is reported to be idiopathic however post-infectious aetiologies dominate across Asia especially secondary to tuberculosis. Most focus to date has been on the study of airway bacteria, both as colonisers and causes of exacerbations. Modern molecular technologies including next generation sequencing (NGS) have become invaluable tools to identify microorganisms directly from sputum and which are difficult to culture using traditional agar based methods. These have provided important insight into our understanding of emerging pathogens in the airways of people with bronchiectasis and the geographical differences that occur. The contribution of the lung microbiome, its ethnic variation, and subsequent roles in disease progression and response to therapy across geographic regions warrant further investigation. This review summarises the known geographical differences in the aetiology, epidemiology and microbiology of bronchiectasis. Further, we highlight the opportunities offered by emerging molecular technologies such as -omics to further dissect out important ethnic differences in the prognosis and management of bronchiectasis.

Non-tuberculous Mycobacterial Infections in Thoracic Transplant Candidates and Recipients

PURPOSE OF REVIEW

To review and discuss the epidemiology, risk factors, clinical presentation, diagnosis, and treatment of non-tuberculous mycobacteria (NTM) in thoracic transplantation.

RECENT FINDINGS

Non-tuberculous mycobacteria are ubiquitous but are an uncommon cause of disease after solid organ transplantation. The incidence of infection is higher in thoracic transplant recipients than in abdominal transplant recipients, with most cases seen after lung transplantation. It is associated with increased morbidity and, occasionally, mortality. Infection in the pre-transplant setting can occur in lung transplant candidates, often posing a dilemma regarding transplant listing. Disease manifestations are diverse, and pulmonary disease is the most common. Diagnosis requires a high index of suspicion. Treatment requires a multiple-drug combination and is limited by drug-drug interactions and tolerability. Mycobacterium abscessus is a challenge in lung transplant recipients, due to its intrinsic resistance and propensity to relapse even after prolonged therapy. Mycobacterium chimaera is an emerging pathogen associated with contamination of heater-cooler units and is described to cause disease months after cardiothoracic surgery. NTM infections in thoracic organ transplant recipients are uncommon but are associated with substantial morbidity and mortality. Data from larger multicenter studies is needed to better define the epidemiology of NTM in thoracic transplantation, best treatment options, and the management of infected transplant candidates.

Microbiological Persistence in Patients With Mycobacterium avium Complex Lung Disease: The Predictors and the Impact on Radiographic Progression

Background

Persistent growth of Mycobacterium avium complex (MAC) in the lungs indicates continuous infection in MAC lung disease (MAC-LD), but its clinical significance has not been investigated. We aimed to evaluate the predictors of persistent culture-positivity for MAC (MAC-PP) and its impact on radiographic deterioration in MAC-LD.

Methods

Patients with MAC-LD at multiple medical centers from 2011 to 2016 were enrolled retrospectively. Microbiological persistence of MAC-LD was defined as MAC-PP exceeding 1 year, in contrast with the negative-conversion group. The outcome was radiographic progression, namely, increased number of involved lung areas or cavitary formation.

Results

Among 126 patients with MAC-LD, 75 (60%) were in the MAC-PP group; these patients had a higher proportion of radiographic progression (54%) than patients in the negative-conversion group (odds ratio [OR], 3.318; 95% confidence interval, 1.146-9.612). Independent predictors of MAC-PP were low body mass index (BMI), radiographic nodular-bronchiectatic (NB) pattern, and increase in the highest grade of acid-fast bacilli smear (AFS). Patients with BMI <21 kg/m2, NB pattern, and positive AFS had an OR of 17.7 for MAC-PP, and those with ≥2 of the factors had a 4.5-fold increased OR for MAC-PP relative to the comparison group. Other than MAC-PP, the highest AFS grade and no anti-MAC treatment were correlated with radiographic progression.

Conclusion

Microbiological persistence in patients with MAC-LD is not uncommon and leads to an increased risk of radiographic progression. The predictors of MAC-PP are low BMI, NB pattern, and high AFS grade; if these risk factors are present, anti-MAC treatment should be seriously considered.

Neutrophil predominance in bronchoalveolar lavage fluid is associated with disease severity and progression of HRCT findings in pulmonary Mycobacterium avium infection

Pulmonary Mycobacterium avium complex (MAC) infection is increasing in prevalence worldwide even in immunocompetent individuals. Despite its variable clinical course, the clinical and immunological factors associated with radiographical severity and progression are not largely unknown. We aimed to study the association between the inflammatory cell and cytokine profiles at the local infected site, and the radiological severity and/or progression of pulmonary MAC infection. In this retrospective cohort study, 22 healthy subjects and 37 consecutive patients who were diagnosed as having pulmonary MAC infection by positive cultures of bronchoalveolar lavage (BAL) fluids were enrolled. The 37 patients were divided into 2 groups based on the predominant BAL inflammatory cell type: the lymphocyte-dominant (LD) group and neutrophil-dominant (ND) groups. The high-resolution computed tomography score in both the lavaged segment and whole lung and cytokines profiles were compared between the 2 groups. The clinical course after the BAL procedure was also compared between the 2 groups. Both the segment and whole lung scores in the ND group were significantly higher than the LD group (P < 0.001). Levels of IL-8 in the BAL fluids were significantly higher in the ND group compared to the LD group (P = 0.01). In contrast, levels of IL-22 were significantly lower in the ND group compared to the LD group (P < 0.001). The prevalence of patients who showed deterioration of the disease was significantly higher in the ND group (83.3%) than the LD group (12.5%) (P < 0.01).

Neutrophil-predominant inflammatory response at the infected site is associated with the radiographical severity and progression of pulmonary MAC infection.

Diagnosis and management of bronchiectasis

KEY POINTS Following a diagnosis of bronchiectasis, it is important to investigate for an underlying cause. Goals of management are to suppress airway infection and inflammation, to improve symptoms and health-related quality of life. There are now validated scoring tools to help assess disease severity, which can help to stratify management. Good evidence supports the use of both exercise training and long-term macrolide therapy in long-term disease management.

Raising awareness of bronchiectasis in primary care: overview of diagnosis and management strategies in adults

Bronchiectasis is a chronic lung disease characterised by recurrent infection, inflammation, persistent cough and sputum production. The disease is increasing in prevalence, requiring a greater awareness of the disease across primary and secondary care. Mild and moderate cases of bronchiectasis in adults can often be managed by primary care clinicians. Initial assessments and long-term treatment plans that include both pharmacological and non-pharmacological treatments, however, should be undertaken in collaboration with a secondary care team that includes physiotherapists and specialists in respiratory medicine. Bronchiectasis is often identified in patients with other lung diseases, such as chronic obstructive pulmonary disease, asthma, and in a lesser but not insignificant number of patients with other inflammatory diseases, such as rheumatoid arthritis and inflammatory bowel disease. Overall goals of therapy are to prevent exacerbations, improve symptoms, improve quality of life and preserve lung function. Prompt treatment of exacerbations with antibiotic therapy is important to limit the impact of exacerbations on quality of life and lung function decline. Patient education and cooperation with health-care providers to implement treatment plans are key to successful disease management. It is important for the primary care provider to work with secondary care providers to develop an individualised treatment plan to optimise care with the goal to delay disease progression. Here, we review the diagnosis and treatment of bronchiectasis with a focus on practical considerations that will be useful to primary care.

Characterizing Non-Tuberculous Mycobacteria Infection in Bronchiectasis

Chronic airway infection is a key aspect of the pathogenesis of bronchiectasis. A growing interest has been raised on non-tuberculous mycobacteria (NTM) infection. We aimed at describing the clinical characteristics, diagnostic process, therapeutic options and outcomes of bronchiectasis patients with pulmonary NTM (pNTM) disease. This was a prospective, observational study enrolling 261 adult bronchiectasis patients during the stable state at the San Gerardo Hospital, Monza, Italy, from 2012 to 2015. Three groups were identified: pNTM disease; chronic P. aeruginosa infection; chronic infection due to bacteria other than P. aeruginosa. NTM were isolated in 32 (12%) patients, and among them, a diagnosis of pNTM disease was reached in 23 cases. When compared to chronic P. aeruginosa infection, patients with pNTM were more likely to have cylindrical bronchiectasis and a "tree-in-bud" pattern, a history of weight loss, a lower disease severity and a lower number of pulmonary exacerbations. Among pNTM patients who started treatment, 68% showed a radiological improvement, and 37% achieved culture conversion without recurrence, while 21% showed NTM isolation recurrence. NTM isolation seems to be a frequent event in bronchiectasis patients, and few parameters might help to suspect NTM infection. Treatment indications and monitoring still remain an important area for future research.