A Systematic Review and Meta-Analysis of the Prevalence and Impact of Pulmonary Bacterial Colonisation in Stable State Chronic Obstructive Pulmonary Disease (COPD)

Bacterial colonisation doubles the risk of exacerbation in alpha-1 antitrypsin deficiency

Pulmonary exacerbations in alpha-1 antitrypsin deficiency (AATD) are associated with worse disease outcomes, including accelerated lung function decline. As with non-deficient COPD, subjects with AATD are predisposed to bacterial colonisation of the lower respiratory tract, a known risk factor for exacerbations. Despite this, the extent to which colonising bacteria contribute to exacerbations remains relatively unexplored. Sputum samples were collected longitudinally from AATD subjects, when clinically stable and during exacerbations, and were processed for quantitative culture to identify bacterial pathogens. Using contemporaneous clinical data, a post-hoc analysis was performed to calculate the odds of an exacerbation in the presence of recognised, potentially pathogenic bacteria (PPB) of the lower respiratory tract. 324 sputum samples were collected from 29 patients with AATD plus radiological evidence of bronchiectasis and 671 samples from 62 patients without bronchiectasis (AATD alone). Both groups contained patients with AATD-associated lung disease (emphysema and chronic bronchitis). At least half of the samples (55.5 %) from AATD alone were positive for a PPB and almost three quarters (72.8 %) of those with bronchiectasis. Presence of a Pseudomonas species, Staphylococcus aureus or Moraxella catarrhalis during stable state disease were all significantly associated with increased likelihood of a subsequent exacerbation (OR: 1.89, p = 0.0013; 1.98, 0.0022; 1.98, 0.0047; 2.19, 0.0047, respectively), independent of age, sex, disease severity (FEV1 impairment), smoking status and presence or absence of bronchiectasis. Disease progression in AATD is variable and identification of traits which may contribute may prove influential. Here, we report that bacterial colonisation is an important predictor of exacerbation in AATD, likely attributed to the associated levels of increased inflammation. Thereby, this may represent a sub cohort of patients that could benefit from additional, targeted therapy.

Advancements and challenges in the management of pneumonia in elderly patients with COPD

INTRODUCTION

Chronic Obstructive Pulmonary Disease (COPD) significantly predisposes the elderly to pneumonia, presenting a complex interplay of pulmonary dysfunction and infection risk.

AREAS COVERED

This article reviews the substantial epidemiologic impact, elucidates the interlinked pathophysiology of COPD and pneumonia, and examines the microbial landscape shaping infection in these patients. It also evaluates management protocols and the multifaceted clinical challenges encountered during treatment.

EXPERT OPINION

Delving into the latest research, we underscore the criticality of preventive measures such as vaccination and present an integrated approach to managing Community-Acquired Pneumonia (CAP) in the COPD demographic. The review also proposes strategic directions for future investigations aimed at enhancing patient outcomes through a deeper understanding of the COPD-pneumonia nexus.

Recreating chronic respiratory infections in vitro using physiologically relevant models

Despite the need for effective treatments against chronic respiratory infections (often caused by pathogenic biofilms), only a few new antimicrobials have been introduced to the market in recent decades. Although different factors impede the successful advancement of antimicrobial candidates from the bench to the clinic, a major driver is the use of poorly predictive model systems in preclinical research. To bridge this translational gap, significant efforts have been made to develop physiologically relevant models capable of recapitulating the key aspects of the airway microenvironment that are known to influence infection dynamics and antimicrobial activity in vivo In this review, we provide an overview of state-of-the-art cell culture platforms and ex vivo models that have been used to model chronic (biofilm-associated) airway infections, including air-liquid interfaces, three-dimensional cultures obtained with rotating-wall vessel bioreactors, lung-on-a-chips and ex vivo pig lungs. Our focus is on highlighting the advantages of these infection models over standard (abiotic) biofilm methods by describing studies that have benefited from these platforms to investigate chronic bacterial infections and explore novel antibiofilm strategies. Furthermore, we discuss the challenges that still need to be overcome to ensure the widespread application of in vivo-like infection models in antimicrobial drug development, suggesting possible directions for future research. Bearing in mind that no single model is able to faithfully capture the full complexity of the (infected) airways, we emphasise the importance of informed model selection in order to generate clinically relevant experimental data.

Time to re-set our thinking about airways disease: lessons from history, the resurgence of chronic bronchitis / PBB and modern concepts in microbiology

In contrast to significant declines in deaths due to lung cancer and cardiac disease in Westernised countries, the mortality due to 'chronic obstructive pulmonary disease' (COPD) has minimally changed in recent decades while 'the incidence of bronchiectasis' is on the rise. The current focus on producing guidelines for these two airway 'diseases' has hindered progress in both treatment and prevention. The elephant in the room is that neither COPD nor bronchiectasis is a disease but rather a consequence of progressive untreated airway inflammation. To make this case, it is important to review the evolution of our understanding of airway disease and how a pathological appearance (bronchiectasis) and an arbitrary physiological marker of impaired airways (COPD) came to be labelled as 'diseases'. Valuable insights into the natural history of airway disease can be obtained from the pre-antibiotic era. The dramatic impacts of antibiotics on the prevalence of significant airway disease, especially in childhood and early adult life, have largely been forgotten and will be revisited as will the misinterpretation of trials undertaken in those with chronic (bacterial) bronchitis. In the past decades, paediatricians have observed a progressive increase in what is termed 'persistent bacterial bronchitis' (PBB). This condition shares all the same characteristics as 'chronic bronchitis', which is prevalent in young children during the pre-antibiotic era. Additionally, the radiological appearance of bronchiectasis is once again becoming more common in children and, more recently, in adults. Adult physicians remain sceptical about the existence of PBB; however, in one study aimed at assessing the efficacy of antibiotics in adults with persistent symptoms, researchers discovered that the majority of patients exhibiting symptoms of PBB were already on long-term macrolides. In recent decades, there has been a growing recognition of the importance of the respiratory microbiome and an understanding of the ability of bacteria to persist in potentially hostile environments through strategies such as biofilms, intracellular communities, and persister bacteria. This is a challenging field that will likely require new approaches to diagnosis and treatment; however, it needs to be embraced if real progress is to be made.

[Take-home messages from the 2nd COPD 2023 Biennial of the French Society of Respiratory Diseases. Placing the patient at the center of the care pathway]

INTRODUCTION

The second COPD Biennial organized by the COPD working group of the French Society of Respiratory Diseases took place in Paris (Cochin) on 13th December 2023.

STATE OF THE ART

Major trends in 2023 were discussed; they encompassed concepts, definitions, biologics, care pathways, pulmonary rehabilitation and complex situations entailed by respiratory infections, cardiovascular comorbidities and pulmonary hypertension, and modalities of oxygen therapy and ventilation.

PERSPECTIVES

The different talks underlined major changes in COPD including the concepts of pre-COPD, etiotypes, health trajectories and new definitions of exacerbation. Recent results in biologics for COPD open the door to new pharmacological options. Assessment of current care pathways in France highlighted some causes for concern. For example, pulmonary rehabilitation is a key but insufficiently practiced element. Respiratory infections require careful assessment and treatments. Diagnosis and treatment of cardiovascular comorbidities and pulmonary hypertension are of paramount importance. As of late, oxygen therapy and ventilation modalities have evolved, and are beginning to afford more personalized options.

CONCLUSIONS

As regards COPD, a personalized approach is crucial, placing the patient at the center of the care pathway and facilitating coordination between healthcare providers.

P. gingivalis alters lung microbiota and aggravates disease severity of COPD rats by up-regulating Hsp90α/MLKL

Background

Epidemiological evidence has confirmed that periodontitis is an essential and independent risk factor of chronic obstructive pulmonary disease (COPD). Porphyromonas gingivalis, a major pathogen implicated in periodontitis, may make a vital contribution to COPD progression. However, the specific effects and molecular mechanism of the link between P. gingivalis and COPD are not clear.

Methods and Results

A COPD rat model was constructed by smoke exposure combined intratracheal instillation of E. coli-LPS, then P. gingivalis was introduced into the oral cavity of COPD rats. This research observed that lower lung function, more severe alveolar damage and inflammation occurred in COPD rats with P. gingivalis group. Meanwhile, P. gingivalis/gingipains could colonize the lung tissues and be enriched in bronchoalveolar lavage fluid (BALF) of COPD rats with P. gingivalis group, along with alterations in lung microbiota. Proteomic analysis suggested that Hsp90α/MLKL-meditated necroptosis pathway was up-regulated in P. gingivalis-induced COPD aggravation, the detection of Hsp90α and MLKL in serum and lung tissue verified that Hsp90α/MLKL was up-regulated.

Conclusion

These results indicate that P. gingivalis could emigrate into the lungs, alter lung microbiota and lead to aggravation of COPD, which Hsp90α/MLKL might participate in.

Associated Factors of Pneumonia in Individuals with Chronic Obstructive Pulmonary Disease (COPD) Apart from the Use of Inhaled Corticosteroids

Inhaled corticosteroids (ICSs) are widely used in chronic obstructive pulmonary disease (COPD) and in combination with long-acting β2 agonists (LABAs) to reduce exacerbations and improve patient lung function and quality of life. However, ICSs have been associated with an increased risk of pneumonia in individuals with COPD, although the magnitude of this risk remains unclear. Therefore, it is difficult to make informed clinical decisions that balance the benefits and adverse effects of ICSs in people with COPD. There may be other causes of pneumonia in patients with COPD, and these causes are not always considered in studies on the risks of using ICSs in COPD. We consider it very useful to clarify these aspects in assessing the influence of ICSs on the incidence of pneumonia and their role in the treatment of COPD. This issue has important implications for current practice and the evaluation and management of COPD, since COPD patients may benefit from specific ICS-based treatment strategies. Many of the potential causes of pneumonia in patients with COPD can act synergistically, so they can be included in more than one section.

Stepwise management of COPD: What is next after bronchodilation?

Inhaled bronchodilator therapy with long-acting muscarinic antagonists (LAMAs) and long-acting β2-agonists (LABAs) in combination is currently the mainstay of treatment for chronic obstructive pulmonary disease (COPD). Treatment guidelines recommend the addition of inhaled corticosteroids (ICS) to LABA/LAMA only in patients with a history of frequent/severe exacerbations and high blood eosinophil counts, or in those with concomitant asthma. Despite this, real-world data suggest that clinicians are not adhering to this guidance and that ICS are frequently overused. This is possibly due to the incorrect assumption that when LABA/LAMA therapy is not sufficient, adding an ICS to the treatment regimen is the logical next step. In this narrative review, we describe global and country-specific guideline recommendations from Germany, Spain, and Japan and compare these with real-world data on LABA/LAMA and ICS use in clinical practice. We also provide a clinical guide to the use of add-on therapies with LABA/LAMA for different patient phenotypes, including (1) patients still symptomatic (but not exacerbating) despite LABA/LAMA treatment; (2) patients still exacerbating despite LABA/LAMA treatment who have high blood eosinophil counts; and (3) patients still exacerbating despite LABA/LAMA treatment who do not have high blood eosinophils or concomitant asthma.

Bacterial Species and Inflammatory Cell Variability in Respiratory Tracts of Patients with Chronic Obstructive Pulmonary Disease Exacerbation: A Multicentric Study

Background and Aim

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) has profound effects on disease progression and patients' quality of life. Emerging evidence suggests an association between alterations in the respiratory microbiome flora species and airway inflammation in patients with AECOPD. The present study aimed to describe the inflammatory cells and bacterial microbiome distributions in respiratory tract in Egyptian patients with AECOPD.

Subjects and Methods

The present cross-sectional study included 208 patients with AECOPD. Sputum and broncho-alveolar lavage samples from the studied patients were submitted to microbial cultures using appropriate media. Total and differential leukocytic counts and were done via automated cell counter.

Results

The present study included 208 AECOPD patients. They comprised 167 males (80.3%) and 41 females (19.7%) with an age of 57.9 ± 4.9 years. AECOPD was categorized as mild, moderate and severe in 30.8%, 43.3% and 26%, respectively. Sputum samples had significantly higher TLC, neutrophil percent and eosinophil percent when compared with BAL samples. In contrast, lymphocyte percent was significantly higher in BAL samples. Sputum specimens had significantly lower frequency of positive growths (70.2% versus 86.5%, p = 0.001). Among the identified organisms, sputum specimens had significantly lower frequency of Strept. pneumoniae (14.4% versus 30.3%, p = 0.001), Klebsiella pneumoniae (19.7% versus 31.7%, p = 0.024), Haemophilus influenzae (12.5% versus 26.9%, p = 0.011), Pseudomonas aeruginosa (2.9% versus 10%, p = 0.019) and Acinetobacter spp. (1.9% versus 7.2%, p = 0.012) growths when compared with BAL samples.

Conclusion

The present study could identify a distinctive pattern of inflammatory cell distribution in sputum and BAL samples of AECOPD patients. The most commonly isolated organisms were Klebsiella pneumoniae and Strept. pneumoniae.

The Impact of Chronic Bronchial Infection in COPD: A Proposal for Management

Up to 50% of patients with chronic obstructive pulmonary disease (COPD) in stable state may carry potentially pathogenic microorganisms (PPMs) in their airways. The presence of PPMs has been associated with increased symptoms, increased risk and severity of exacerbations, a faster decline in lung function and impairment in quality of life. Although some clinical trials have demonstrated a reduction in exacerbations in patients chronically treated with systemic antibiotics, particularly macrolides, the selection of patients was based on the previous frequency of exacerbations and not on the presence of PPMs in their airways. Therefore, unlike in bronchiectasis, there is a lack of evidence-based recommendations for assessment and treatment of the presence of PPMs in either single or repeated isolations in COPD. In this article, we propose that chronic bronchial infection (CBI) in COPD be defined as the isolation of the same PPM in at least three sputum samples separated by more than one month; we review the impact of CBI on the natural course of COPD and suggest a course of action in patients with a single isolation of a PPM or suspected CBI. Antibiotic treatment in stable COPD should be recommended based on four main criteria: a) the presence of comorbid bronchiectasis, b) the demonstration of a single or multiple isolation of the same PPM, c) the clinical impact of CBI on the patients, and d) the type of PPM, either Pseudomonas aeruginosa or non-pseudomonal PPM. These recommendations are derived from evidence generated in patients with bronchiectasis and, until new evidence specifically obtained in COPD is available, they may help in the management of these challenging patients with COPD. Existing evidence suggests that inhaled therapy is insufficient to manage patients with moderate-to-severe COPD, frequent exacerbations, and CBI. New studies must be conducted in this particularly demanding population.