The microbiome in bronchiectasis

Bronchiectasis is increasing in prevalence worldwide, yet current treatments available are limited to those alleviating symptoms and reducing exacerbations. The pathogenesis of the disease and the inflammatory, infective and molecular drivers of disease progression are not fully understood, making the development of novel treatments challenging. Understanding the role bacteria play in disease progression has been enhanced by the use of next-generation sequencing techniques such as 16S rRNA sequencing. The microbiome has not been extensively studied in bronchiectasis, but existing data show lung bacterial communities dominated by Pseudomonas, Haemophilus and Streptococcus, while exhibiting intraindividual stability and large interindividual variability. Pseudomonas- and Haemophilus-dominated microbiomes have been shown to be linked to severe disease and frequent exacerbations. Studies completed to date are limited in size and do not fully represent all clinically observed disease subtypes. Further research is required to understand the microbiomes role in bronchiectasis disease progression. This review discusses recent developments and future perspectives on the lung microbiome in bronchiectasis.

The efficacy and safety of inhaled antibiotics for the treatment of bronchiectasis in adults: a systematic review and meta-analysis

BACKGROUND

Although use of inhaled antibiotics is the standard of care in cystic fibrosis, there is insufficient evidence to support use of inhaled antibiotics in patients with bronchiectasis not due to cystic fibrosis. We aimed to assess the efficacy and safety of inhaled antibiotics for the long-term treatment of adults with bronchiectasis and chronic respiratory tract infections.

METHODS

We did a systematic review and meta-analysis of all randomised controlled trials of inhaled-antibiotic use in adult patients with bronchiectasis and chronic respiratory tract infections. Eligible publications were identified by searching MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and ClinicalTrials.gov. Randomised controlled trials of inhaled antibiotics were included if the patients were adults with stable bronchiectasis diagnosed by CT or bronchography, the trials had treatment a duration of at least 4 weeks, and their outcomes met at least one of the endpoints of interest. Studies in cystic fibrosis were excluded. Efficacy endpoints assessed were bacterial load, bacterial eradication from sputum, frequency of exacerbations, time to first exacerbation, proportion of patients with at least one exacerbation, frequency of severe exacerbations, quality of life, change in FEV₁, 6-min walk distance, mortality, adherence to treatment, and sputum volume; safety endpoints were adverse events and bacterial resistance in sputum. Each study was independently reviewed for methodological quality using the Cochrane risk of bias tool. Random-effects meta-analysis was used to pool individual studies. Heterogeneity was assessed using I². The review is registered on PROSPERO, number CRD42019122892.

FINDINGS

16 trials (n=2597 patients) were included for analysis. The mean reduction of colony forming units per g of sputum with inhaled antibiotics was -2·32 log units (95% CI -3·20 to -1·45; p<0·0001). Bacterial eradication was increased with inhaled antibiotic therapy (odds ratio [OR] 3·36, 1·63 to 6·91; p=0·0010). Inhaled antibiotics significantly reduced exacerbation frequency (rate ratio 0·81, 0·67 to 0·97; p=0·020). Time to first exacerbation was significantly prolonged with inhaled antibiotics (hazard ratio 0·83, 0·69 to 0·99; p=0·028). The proportion of patients with at least one exacerbation decreased (risk ratio 0·85, 0·74 to 0·97; p=0·015). There was a significant reduction in the frequency of severe exacerbations (rate ratio 0·43, 0·24 to 0·78; p=0·0050). The scores for neither the Quality of Life Bronchiectasis questionnaire nor St George's Respiratory Questionnaire improved above the minimal clinically important difference. The relative change in FEV₁ was a deterioration of 0·87% predicted value (-2·00 to 0·26%; p=0·13). Other efficacy endpoints were reported in only few studies or had few events. There was no difference in treatment-emergent adverse effects (OR 0·97, 0·67 to 1·40; p=0·85) or bronchospasm (0·99, 0·66 to 1·48; p=0·95). Emergence of bacterial resistance was evident at the end of the treatment period (risk ratio 1·91, 1·46 to 2·49; p<0·0001).

INTERPRETATION

Inhaled antibiotics are well tolerated, reduce bacterial load, and achieve a small but statistically significant reduction in exacerbation frequency without clinically significant improvements in quality of life in patients with bronchiectasis and chronic respiratory tract infections.

FUNDING

British Lung Foundation through the GSK/British Lung Foundation Chair of Respiratory Research and European Respiratory Society through the EMBARC2 consortium. EMBARC2 is supported by project partners Chiesi, Grifols, Insmed, Novartis, and Zambon.

Antimicrobial peptides, disease severity and exacerbations in bronchiectasis

Rationale

Recently a frequent exacerbator phenotype has been described in bronchiectasis, but the underlying biological mechanisms are unknown. Antimicrobial peptides (AMPs) are important in host defence against microbes but can be proinflammatory in chronic lung disease.

Objectives

To determine pulmonary and systemic levels of AMP and their relationship with disease severity and future risk of exacerbations in bronchiectasis.

Methods

A total of 135 adults with bronchiectasis were prospectively enrolled at three European centres. Levels of cathelicidin LL-37, lactoferrin, lysozyme and secretory leucocyte protease inhibitor (SLPI) in serum and sputum were determined at baseline by ELISA. Patients were followed up for 12 months. We examined the ability of sputum AMP to predict future exacerbation risk.

Measurements and main results

AMP levels were higher in sputum than in serum, suggesting local AMP release. Patients with more severe disease at baseline had dysregulation of airway AMP. Higher LL-37 and lower SLPI levels were associated with Bronchiectasis Severity Index, lower FEV1 (forced expiratory volume in 1 s) and Pseudomonas aeruginosa infection. Low SLPI levels were also associated with the exacerbation frequency at baseline. During follow-up, higher LL-37 and lower SLPI levels were associated with a shorter time to the next exacerbation, whereas LL-37 alone predicted exacerbation frequency over the next 12 months.

Conclusions

Patients with bronchiectasis showed dysregulated sputum AMP levels, characterised by elevated LL-37 and reduced SLPI levels in the frequent exacerbator phenotype. Elevated LL-37 and reduced SLPI levels are associated with Pseudomonas aeruginosa infection and can predict future risk of exacerbations in bronchiectasis.

A point-of-care neutrophil elastase activity assay identifies bronchiectasis severity, airway infection and risk of exacerbation

Introduction

Neutrophil elastase activity in sputum can identify patients at high risk of airway infection and exacerbations in bronchiectasis. Application of this biomarker in clinical practice is limited, because no point-of-care test is available. We tested whether a novel semi-quantitative lateral flow device (neutrophil elastase airway test stick – NEATstik®) can stratify bronchiectasis patients according to severity, airway infection and exacerbation risk.

Methods

Sputum samples from 124 patients with stable bronchiectasis enrolled in the UK and Spain were tested using the NEATstik®, which scores neutrophil elastase concentration from 0 (<8 µg·mL−1 elastase activity) to 10 (maximum detectable neutrophil elastase activity). High neutrophil elastase activity was regarded as a NEATstik® grade >6. Severity of disease, airway infection from sputum culture and exacerbations over the 12 months were recorded. An independent validation was conducted in 50 patients from Milan, Italy.

Measurements and main results

Patients had a median age of 69 years and forced expiratory volume in 1 s (FEV1) 69%. High neutrophil elastase activity was associated with worse bronchiectasis severity using the bronchiectasis severity index (p=0.0007) and FEV1 (p=0.02). A high NEATstik® grade was associated with a significant increase in exacerbation frequency, incident rate ratio 2.75 (95% CI 1.63–4.64, p<0.001). The median time to next exacerbation for patients with a NEATstik® grade >6 was 103 days compared to 278 days. The hazard ratio was 2.59 (95% CI 1.71–3.94, p<0.001). Results were confirmed in the independent validation cohort.

Conclusions

A novel lateral flow device provides assessment of neutrophil elastase activity from sputum in minutes and identifies patients at increasing risk of airway infection and future exacerbations.

Pulmonary rehabilitation after exacerbation of bronchiectasis: a pilot randomized controlled trial

BACKGROUND

Pulmonary rehabilitation improves exercise capacity and reduces risk of future exacerbation in COPD when performed after an exacerbation. There have been no previous studies of post-exacerbation rehabilitation in bronchiectasis.

METHODS

Parallel group randomized controlled trial compared pulmonary rehabilitation (PR) to standard care (SC) in patients followed an antibiotic treated exacerbation of bronchiectasis. Patients were randomized following a 14 day course of antibiotics was completed. The primary outcome was 6-min walk distance (6 MW) at 8 weeks. Secondary outcomes were time to the next exacerbation, St.Georges Respiratory Questionnaire, COPD CAT score, Leicester cough questionnaire (LCQ) and FEV1 at 8 and 12 weeks post exacerbation.

RESULTS

Forty eight patients were enrolled but only 27 had exacerbations within 12 months of enrolment. Nine patients received pulmonary rehabilitation and 18 received standard care. The 6 MW improved significantly from post-exacerbation to 8 weeks in both groups, with no significant difference between PR and SC- mean difference of 11 m (95% CI -34.3 to 56.3,p = 0.6). Time to the next exacerbation was not significantly different hazard ratio 0.83 (0.31-2.19, p = 0.7). No significant differences were seen between groups in terms of LCQ, CAT, FEV1 or SGRQ between groups. An analysis of probability based on the patients enrolled suggested > 1000 subjects are likely be required to have an > 80% probability of observing a statistically significant difference between PR and SC and any such differences would be likely to be too small to be clinically relevant.

CONCLUSIONS

This pilot study identified no significant benefits associated with pulmonary rehabilitation after exacerbations of bronchiectasis.

TRIAL REGISTRATION

NCT02179983, registered on Clinicaltrials.gov 29th June 2014.

Microbiological changes observed over 48 weeks of treatment with inhaled liposomal ciprofloxacin in individuals with non-cystic fibrosis bronchiectasis and chronic Pseudomonas aeruginosa lung infection

OBJECTIVES

Non-cystic fibrosis bronchiectasis (NCFBE) with Pseudomonas aeruginosa has been associated with increased pulmonary exacerbation (PEx) and mortality risk. European Respiratory Society guidelines conditionally recommend inhaled antimicrobials for persons with NCFBE, P aeruginosa and three or more PEx/year. We report microbiological results of two randomized, 48-week placebo-controlled trials of ARD-3150 (inhaled liposomal ciprofloxacin) in individuals with NCFBE with P aeruginosa and PEx history [Lancet Respir Med 2019;7:213-26].

METHODS

Respiratory secretions from 582 participants receiving up to six 28-day on/off treatment cycles were analysed for sputum P. aeruginosa, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus and Escherichia coli densities, P. aeruginosa susceptibilities to ciprofloxacin and nine other antimicrobials, and prevalence of other bacterial opportunists. Associations between PEx risk and sputum density, antimicrobial susceptibility and opportunist prevalence changes were studied.

RESULTS

Sputum P. aeruginosa density reductions from baseline after ARD-3150 treatments ranged from 1.77 (95% CI 2.13-1.40) versus 0.54 (95% CI 0.89-0.19) log₁₀ CFU/g for placebo (second period) to 2.07 (95% CI 2.45-1.69) versus 0.70 (95% CI 1.11-0.29) log₁₀ CFU/g for placebo (fourth period) with only modest correlation between density reduction magnitude and PEx benefit. ARD-3150 (but not placebo) treatment was associated with increased P. aeruginosa ciprofloxacin MIC but not emergence of other bacterial opportunists across the study; ciprofloxacin MIC₅₀ increased from 0.5 to 1 mg/L, MIC₉₀ increased from 4 to 16 mg/L. Other antimicrobial MIC were mostly unaffected.

CONCLUSION

Microbiological changes over 48 weeks of ARD-3150 treatment appear modest. Ciprofloxacin susceptibility (but not other antimicrobial susceptibility) decreases were observed that did not appear to preclude PEx risk reduction benefit.

Personalised anti-inflammatory therapy for bronchiectasis and cystic fibrosis: selecting patients for controlled trials of neutrophil elastase inhibition

Background

Neutrophil elastase (NE) has been linked to lung neutrophil dysfunction in bronchiectasis and cystic fibrosis (CF), making NE inhibition a potential therapeutic target. NE inhibitor trials have given mixed result perhaps because not all patients have elevated airway NE activity.

Methods

We tested whether a single baseline sputum NE measurement or a combination of clinical parameters could enrich patient populations with elevated NE activity for "personalised medicine". Intra- and interindividual variations of total and active NE levels in induced sputum from patients with CF or bronchiectasis were monitored over 14 days. Patients with established CF and bronchiectasis (n=5 per group) were recruited. NE was measured using three different methods: one total and two active NE assays. Subsequently, we analysed the association between clinical parameters and NE from a large bronchiectasis cohort study (n=381).

Results

All three assays showed a high degree of day-to-day variability (0-233% over 14 days). There were strong correlations found between all assays (p<0.0001). Despite high day-to-day variability, patients could be stratified into "high" or "low" groups based on moderate cut-off levels. In the bronchiectasis cohort study, factors most associated with high sputum NE levels were: Pseudomonas aeruginosa infection (β-estimate 11.5, 95% CI -6.0-29.0), sputum colour (β-estimate 10.4, 95% CI 4.3-16.6), Medical Research Council dyspnoea score (β-estimate 6.4, 95% CI 1.4-11.4) and exacerbation history (β-estimate 3.4, 95% CI 1.4-5.3). Collectively, P. aeruginosa infection, sputum colour and exacerbation frequency provided the greatest specificity for "high" NE (98.7%, 95% CI 7.0-99.6%).

Conclusion

These results show that patients with bronchiectasis and CF can be effectively divided into "high" or "low" groups, based on sputum NE assays or clinical inclusion criteria.

A systematic review of pharmacotherapeutic clinical trial end-points for bronchiectasis in adults

Bronchiectasis is an increasing clinical problem, but multiple recent clinical trials have failed to reach their primary end-point. Difficulties in achieving “positive” bronchiectasis trials is reflected in a lack of agreement from trialists and regulators on what are the optimal end-points.

To evaluate the use of end-points in bronchiectasis trials, we conducted a systematic review of published bronchiectasis trials from 2008 to 2018 and extracted end-points used, definitions, methods of analysis and responsiveness.

Our analysis shows that quality of life and exacerbation end-points are most frequently used. Trials using exacerbation end-points have been characterised by varying definitions, multiple methods of analysis and durations of follow-up. There are multiple quality of life tools for bronchiectasis (Quality of Life – Bronchiectasis questionnaire, St George's Respiratory Questionnaire, etc.). The majority of studies measure lung function (e.g. forced expiratory volume in 1 s), but this is shown to be nonresponsive to the majority of interventions. Microbiology end-points frequently show statistically significant differences in phase 2 antibiotic studies but their correlation with clinical end-points is unknown.

This systematic review demonstrates a need for guidance to standardise definitions and design features to improve reproducibility and increase the likelihood of demonstrating statistically significant benefits with new therapies.

There is an urgent need to standardise clinical trial end-points in bronchiectasis. This systematic review shows the diversity of end-points used in bronchiectasis and suggests approaches that may improve the success rate and reproducibility of trials.http://ow.ly/d4HR30nvvS3

The economic burden of bronchiectasis - known and unknown: a systematic review

Background

The increasing prevalence and recognition of bronchiectasis in clinical practice necessitates a better understanding of the economic disease burden to improve the management and achieve better clinical and economic outcomes. This study aimed to assess the economic burden of bronchiectasis based on a review of published literature.

Methods

A systematic literature review was conducted using MEDLINE, Embase, EconLit and Cochrane databases to identify publications (1 January 2001 to 31 December 2016) on the economic burden of bronchiectasis in adults.

Results

A total of 26 publications were identified that reported resource use and costs associated with management of bronchiectasis. Two US studies reported annual incremental costs of bronchiectasis versus matched controls of US$5681 and US$2319 per patient. Twenty-four studies reported on hospitalization rates or duration of hospitalization for patients with bronchiectasis. Mean annual hospitalization rates per patient, reported in six studies, ranged from 0.3–1.3, while mean annual age-adjusted hospitalization rates, reported in four studies, ranged from 1.8–25.7 per 100,000 population. The average duration of hospitalization, reported in 12 studies, ranged from 2 to 17 days. Eight publications reported management costs of bronchiectasis. Total annual management costs of €3515 and €4672 per patient were reported in two Spanish studies. Two US studies reported total costs of approximately US$26,000 in patients without exacerbations, increasing to US$36,00–37,000 in patients with exacerbations. Similarly, a Spanish study reported higher total annual costs for patients with > 2 exacerbations per year (€7520) compared with those without exacerbations (€3892). P. aeruginosa infection increased management costs by US$31,551 to US$56,499, as reported in two US studies, with hospitalization being the main cost driver.

Conclusions

The current literature suggests that the economic burden of bronchiectasis in society is significant. Hospitalization costs are the major driver behind these costs, especially in patients with frequent exacerbations. However, the true economic burden of bronchiectasis is likely to be underestimated because most studies were retrospective, used ICD-9-CM coding to identify patients, and often ignored outpatient burden and cost. We present a conceptual framework to facilitate a more comprehensive assessment of the true burden of bronchiectasis for individuals, healthcare systems and society.

Electronic supplementary material

The online version of this article (10.1186/s12890-019-0818-6) contains supplementary material, which is available to authorized users.

Challenges in severe community-acquired pneumonia: a point-of-view review

Purpose

Severe community-acquired pneumonia (SCAP) is still associated with substantial morbidity and mortality. In this point-of-view review paper, a group of experts discuss the main controversies in SCAP: the role of severity scores to guide patient settings of care and empiric antibiotic therapy; the emergence of pathogens outside the core microorganisms of CAP; viral SCAP; the best empirical treatment; septic shock as the most lethal complication; and the need for new antibiotics.

Methods

For all topics, the authors describe current controversies and evidence and provide recommendations and suggestions for future research. Evidence was based on meta-analyses, most recent RCTs and recent interventional or observational studies. Recommendations were reached by consensus of all the authors.

Results and conclusions

The IDSA/ATS criteria remain the most pragmatic tool to predict ICU admission. The authors recommend a combination of a beta-lactam/beta-lactamase inhibitor or a third G cephalosporin plus a macrolide in most SCAP patients, and to empirically cover PES (P. aeruginosa, extended spectrum beta-lactamase producing Enterobacteriaceae, methicillin-resistant S. aureus) pathogens when at least two specific risk factors are present. In patients with influenza CAP, the authors recommend the use of oseltamivir and avoidance of the use of steroids. Corticosteroids can be used in case of refractory shock and high systemic inflammatory response.

British Thoracic Society guideline for bronchiectasis in adults

The full British Thoracic Society Guideline for Bronchiectasis in Adults is published in Thorax. The following is a summary of the recommendations and good practice points. The sections referred to in the summary refer to the full guideline. The appendices are available in the full guideline.

The effect of changes to GOLD severity stage on long term morbidity and mortality in COPD

BACKGROUND

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) severity stage classifies Chronic Obstructive Pulmonary Disease (COPD) into groups based on symptoms, exacerbations and forced expiratory volume in one second (FEV1). This allows patients to change to less severe COPD stages, a novel aspect of assessment not previously evaluated. We aimed to investigate the association between temporal changes in GOLD severity stage and outcomes in COPD patients.

METHODS

This was a record-linkage study using patients registered with a Scottish regional COPD network 2000-2015. Annual spirometry & symptoms were recorded and linked to healthcare records to identify exacerbations, hospitalisations and mortality. Spirometry, modified Medical Research Council (mMRC) dyspnoea scale and acute exacerbations over the previous year were used to assign GOLD severity at each visit. A time-dependent Cox model was used to model time to death. Secondary outcomes were respiratory specific mortality and hospitalisations. Effect sizes are expressed as Hazard Ratios HR (95%CI).

RESULTS

Four thousand, eight hundred and eighty-five patients (mean age 67.3 years; 51.3% female) with 21,348 visits were included. During a median 6.6 years follow-up there were 1530 deaths. For the secondary outcomes there were 712 respiratory deaths and 1629 first hospitalisations. Across 16,463 visit-pairs, improvement in COPD severity was seen in 2308 (14%), no change in 11,010 (66.9%) and worsening in 3145 (19.1). Compared to patients staying in GOLD stage A, those worsening had a stepwise increased mortality and hospitalisations.

CONCLUSIONS

Improving COPD severity classification was associated with reduced mortality and worsening COPD severity was associated with increased mortality and hospitalisations. Change in GOLD group has potential as monitoring tool and outcome measure in clinical trials.

Economic burden of bronchiectasis in Germany

Estimates of healthcare costs for incident bronchiectasis patients are currently not available for any European country.

Out of a sample of 4 859 013 persons covered by German statutory health insurance companies, 231 new bronchiectasis patients were identified in 2012. They were matched with 685 control patients by age, sex and Charlson Comorbidity Index, and followed for 3 years.

The total direct expenditure during that period per insured bronchiectasis patient was EUR18 634.57 (95% CI EUR15 891.02–23 871.12), nearly one-third higher (ratio of mean 1.31, 95% CI 1.02–1.68) than for a matched control (p<0.001). Hospitalisation costs contributed to 35% of the total and were >50% higher in the bronchiectasis group (ratio of mean 1.56, 95% CI 1.20–3.01; p<0.001); on average, bronchiectasis patients spent 4.9 (95% CI 2.27–7.43) more days in hospital (p<0.001). Antibiotics expenditures per bronchiectasis outpatient (EUR413.81) were nearly 5 times higher than those for a matched control (ratio of mean 4.85, 95% CI 2.72–8.64). Each bronchiectasis patient had on average 40.5 (95% CI 17.1–43.5) sick-leave days and induced work-loss costs of EUR4230.49 (95% CI EUR2849.58–5611.20). The mortality rate for bronchiectasis and matched non-bronchiectasis patients after 3 years of follow-up was 26.4% and 10.5%, respectively (p<0.001). Mortality in the bronchiectasis group was higher among those who also had chronic obstructive lung disease than in patients with bronchiectasis alone (35.9% and 14.6%, respectively; p<0.001).

Although bronchiectasis is considered underdiagnosed, the mortality and associated financial burden in Germany are substantial.

ERS syllabus for postgraduate training in respiratory infections: a guide for comprehensive training

Respiratory infections, including tuberculosis, represent one of the leading causes of morbidity and mortality across the world. They represent the deadliest communicable diseases causing 3.0 million deaths worldwide in 2016 [1]. The burden of respiratory infections can be unbearable for some health systems: they represent one of the most common reasons for doctor visits, regardless of age and sex [2].

ERS has developed a syllabus for postgraduate training in respiratory infections to guide programme designershttp://ow.ly/xJ0R30m8CYB