Non-cystic fibrosis bronchiectasis

A systematic literature review of the clinical and socioeconomic burden of bronchiectasis

BACKGROUND

The overall burden of bronchiectasis on patients and healthcare systems has not been comprehensively described. Here, we present the findings of a systematic literature review that assessed the clinical and socioeconomic burden of bronchiectasis with subanalyses by aetiology (PROSPERO registration: CRD42023404162).

METHODS

Embase, MEDLINE and the Cochrane Library were searched for publications relating to bronchiectasis disease burden (December 2017-December 2022). Journal articles and congress abstracts reporting on observational studies, randomised controlled trials and registry studies were included. Editorials, narrative reviews and systematic literature reviews were included to identify primary studies. PRISMA guidelines were followed.

RESULTS

1585 unique publications were identified, of which 587 full texts were screened and 149 were included. A further 189 citations were included from reference lists of editorials and reviews, resulting in 338 total publications. Commonly reported symptoms and complications included dyspnoea, cough, wheezing, sputum production, haemoptysis and exacerbations. Disease severity across several indices and increased mortality compared with the general population was reported. Bronchiectasis impacted quality of life across several patient-reported outcomes, with patients experiencing fatigue, anxiety and depression. Healthcare resource utilisation was considerable and substantial medical costs related to hospitalisations, treatments and emergency department and outpatient visits were accrued. Indirect costs included sick pay and lost income.

CONCLUSIONS

Bronchiectasis causes significant clinical and socioeconomic burden. Disease-modifying therapies that reduce symptoms, improve quality of life and reduce both healthcare resource utilisation and overall costs are needed. Further systematic analyses of specific aetiologies and paediatric disease may provide more insight into unmet therapeutic needs.

The diagnostic utility of microscopic quality assessment of sputum samples in the era of rapid syndromic PCR testing

This prospective study assessed the value of initial microscopy evaluation of sputum samples submitted for rapid syndromic PCR-based testing. Bacterial detections by the BioFire FilmArray Pneumonia Panel plus in 126 high- and 108 low-quality sputum samples, based on initial microscopy evaluation in samples from patients with lower respiratory tract infections were compared. We found that high-quality samples had a higher proportion of bacterial detections compared to low-quality samples (P = 0.013). This included a higher proportion of detections of bacteria deemed clinically relevant by predefined criteria (70% and 55%, P = 0.016), as well as a higher proportion of detections of Haemophilus influenzae (36% and 20%, P = 0.010). High-quality samples also had more detections of bacteria with high semi-quantitative values. The study found no significant difference between high- and low-quality samples in the proportions of samples with a single species of bacteria detected, samples with a bacteria treated by the clinician, samples with detection of a proven etiology of community-acquired pneumonia by predefined criteria, the number of bacterial species detected, or the detection of Streptococcus pneumoniae, Moraxella catarrhalis, or Staphylococcus aureus. The results showed that 40% (95% CI 35%-47%) of the bacterial detections would have been missed if only high-quality samples were analyzed. This included 41% (27%-56%) of detections of S. pneumoniae, 33% (23%-45%) of detections of H. influenzae, 42% (28%-58%) of detections of S. aureus, and 37% (23%-54%) of detections of M. catarrhalis. These findings suggest that all sputum samples submitted for rapid syndromic PCR testing should be analyzed, regardless of initial microscopy quality assessment. (This study has been registered at ClinicalTrials.gov under registration no. NCT04660084.) IMPORTANCE Microscopic quality assessment of sputum samples was originally designed for sputum culture, and its applicability in today's workflow, which includes syndromic PCR testing, may differ. Addressing this crucial gap, our study emphasizes the need to optimize the use and workflow of syndromic PCR panels, like the BioFire FilmArray Pneumonia plus (FAP plus), in microbiology laboratories. These advanced PCR-based tests offer rapid and comprehensive pathogen detection for respiratory infections, yet their full potential remains uncertain. By comparing bacterial detections in high- and low-quality sputum samples, we underscore the importance of including low-quality samples in testing. Our findings reveal a significant proportion of potentially clinically relevant bacterial detections that would have been missed if only high-quality samples were analyzed. These insights support the efficient implementation of syndromic PCR panels, ultimately enhancing patient care and outcomes.

The effect of azithromycin on sputum inflammatory markers in bronchiectasis

BACKGROUND

Long term macrolide treatment has been found beneficial in bronchiectasis (BE) -pathogical bronchial dilatation- possibly due to a combined anti-bacterial and immunomodulatory effect. The exact mechanism of inflammatory response is unknown. Here, we investigated the effect of maintenance macrolide treatment on the inflammatory response in BE. In addition, we assessed the inflammatory profile in BE in relation to disease severity.

METHODS

During the BAT randomized controlled trial (investigating the effect of 1 year of azithromycin (AZM) in 83 BE patients), data on BE severity, lung function and sputum microbiology was collected. For the current study, a wide range of inflammatory markers were analysed in 3- monthly sputum samples in all participants.

RESULTS

At baseline, marked neutrophilic but also eosinophilic inflammation was present in both groups, which remained stable throughout the study and was not affected by AZM treatment. Significant upregulation of pro-inflammatory markers correlated with FEV₁ < 50% (TNFα, ECP, IL-21, IL-1, p = 0.01- 0.05), H. influenzae (HI) colonization (MPO, ECP, MIP-1, TNFα, IL-21, Il-8, IL-1, IL-1α, p < 0.001 - 0.04) and number of exacerbations (MPO, ECP, VEGF, MMP-9, p = 0.003 - 0.01). Surprisingly, colonization with P. aeruginosa (PA) was found to correlate with an attenuated inflammatory response compared to non-PA colonized. In placebo-treated patients, presence of an infectious exacerbation was reflected by a significant excessive increase in inflammation as compared to a non-significant upregulation in the AZM-treated patients.

CONCLUSION

One year of AZM treatment did not result in attenuation of the inflammatory response in BE. Increasing disease severity and the presence of an exacerbation were reflected by upregulation of pro-inflammatory markers.

Risk factors for multidrug-resistant pathogens in bronchiectasis exacerbations

BACKGROUND

Non-cystic fibrosis bronchiectasis is a chronic structural lung condition that courses with recurrent infectious exacerbations that lead to frequent antibiotic treatment making this population more susceptible to acquire pathogens with antibiotic resistance. We aimed to investigate risk factors associated with isolation of multidrug-resistant pathogens in bronchiectasis exacerbations.

METHODS

A prospective observational study was conducted in two tertiary-care hospitals, enrolling patients when first exacerbation appeared. Multidrug-resistance was determined according to European Centre of Diseases Prevention and Control classification.

RESULTS

Two hundred thirty three exacerbations were included and microorganisms were isolated in 159 episodes. Multidrug-resistant pathogens were found in 20.1% episodes: Pseudomonas aeruginosa (48.5%), methicillin-resistant Staphylococcus aureus (18.2%) and Extended spectrum betalactamase + Enterobacteriaceae (6.1%), and they were more frequent in exacerbations requiring hospitalization (24.5% vs. 10.2%, p: 0.016). Three independent multidrug-resistant risk factors were found: chronic renal disease (Odds ratio (OR), 7.60, 95% CI 1.92-30.09), hospitalization in the previous year (OR, 3.88 95% CI 1.37-11.02) and prior multidrug-resistant isolation (OR, 5.58, 95% CI 2.02-15.46). The proportion of multidrug-resistant in the 233 exacerbations was as follows: 3.9% in patients without risk factors, 12.6% in those with 1 factor and 53.6% if ≥2 risk factors.

CONCLUSIONS

Hospitalization in the previous year, chronic renal disease, and prior multidrug-resistant isolation are risk factors for identification multidrug-resistant pathogens in exacerbations. This information may assist clinicians in choosing empirical antibiotics in daily clinical practice.

Mechanisms of immune dysfunction and bacterial persistence in non-cystic fibrosis bronchiectasis

Bronchiectasis is a chronic inflammatory lung disease. The underlying cause is not identified in the majority of patients, but bronchiectasis is associated with a number of severe infections, immunodeficiencies and autoimmune disorders. Regardless of the underlying cause, the disease is characterised by a vicious cycle of bacterial colonisation, airway inflammation and airway structural damage. Inflammation in bronchiectasis is predominantly neutrophil driven. Neutrophils migrate to the airway under the action of pro-inflammatory cytokines such as interleukin-8, tumour necrosis factor-α and interleukin-1β, all of which are increased in the airway of patients with bronchiectasis. Bacterial infection persists in the airway despite large numbers of neutrophils that would be expected to phagocytose and kill pathogens under normal circumstances. Evidence suggests that neutrophils are disabled by multiple mechanisms including cleavage of phagocytic receptors by neutrophil elastase and inhibition of phagocytosis by neutrophil peptides. Complement activation is impaired and neutrophil elastase may cleave activated complement from pathogens preventing effective opsonisation. Organisms also evade clearance by adapting to chronic infection. The formation of biofilms, reduced motility and the down-regulation of virulence factors are among the strategies used to subvert innate immune mechanisms. Greater understanding of the mechanisms underlying chronic colonisation in bronchiectasis will assist in the development of new treatments for this important disease.

Do processing time and storage of sputum influence quantitative bacteriology in bronchiectasis?

This study aimed to establish whether the bacterial density of spontaneous sputum is affected by the time and mode of sample storage. Ten patients with bronchiectasis collected all sputum expectorated over 45 min. The samples were aliquoted and processed at 25 °C for qualitative and quantitative bacteriology at 1, 2, 4 and 6 h from expectoration. Further aliquots were stored at 25 °C, 4 °C and −20 °C for 24 and 48 h prior to processing. The species present was identified and median (interquartile range) sputum log10 bacterial density (c.f.u. ml−1) calculated. All samples cultured grew Pseudomonas aeruginosa and for two patients Staphylococcus aureus additionally grew for all samples. There was no significant difference in P. aeruginosa density in samples processed at 1, 2, 4 and 6 h following expectoration [8.2 (7.8–8.3) c.f.u. ml−1, 8.0 (7.8–8.3) c.f.u. ml−1, 8.0 (7.9–8.2) c.f.u. ml−1, 8.1 (7.9–8.2) c.f.u. ml−1, respectively, P=0.392]. Storage for 24 and 48 h at 4 °C did not significantly change the bacterial load compared with processing at 1 h [8.03 (7.6–8.2) c.f.u. ml−1, P=0.07, and 7.96 (7.49–8.22) c.f.u. ml−1, P=0.09, respectively]. Storage for 24 and 48 h at −20 °C significantly reduced P. aeruginosa density [7.1 (6.1–7.7) c.f.u. ml−1, P=0.005, and 6.9 (6.2–7.6) c.f.u. ml−1, P=0.008, respectively]. Storage at 25 °C for 24 and 48 h was associated with a significant increase in bacterial load [8.3 (8.1–8.6) c.f.u. ml−1, P=0.009, and 8.4 (8.1–8.5) c.f.u. ml−1, P=0.03, respectively]. Bacterial density was not affected by storage for up to 6 h following expectoration at 25 °C; beyond this, storage at 4 °C is preferred.