Pseudomonas aeruginosa and risk of death and exacerbations in patients with chronic obstructive pulmonary disease: an observational cohort study of 22 053 patients

Ubiquitin-specific protease-7 promotes expression of airway mucin MUC5AC via the NF-κB signaling pathway

Chronic obstructive pulmonary disease (COPD) and other respiratory diseases frequently present with airway mucus hypersecretion, which not only affects the patient's quality of life but also poses a constant threat to their life expectancy. Ubiquitin-specific protease 7 (USP7), a deubiquitinating enzyme, affects cell differentiation, tissue growth, and disease development. However, its role in airway mucus hypersecretion induced by COPD remains elusive. In this study, USP7 expression was significantly upregulated in airway epithelial samples from patients with COPD, and USP7 was also overexpressed in mouse lung and human airway epithelial cells in models of airway mucus hypersecretion. Inhibition of USP7 reduced the expression of nuclear factor kappa B (NF-κB), phosphorylated-NF-κB (p-NF-κB), and phosphonated inhibitor of nuclear factor kappa B (p-IκBα), and alleviated the airway mucus hypersecretion in vivo and in vitro. Further research revealed that USP7 stimulated airway mucus hypersecretion through the activation of NF-κB nuclear translocation. In addition, the expression of mucin 5AC (MUC5AC) was suppressed by the NF-κB inhibitor erdosteine. These findings suggest that USP7 stimulates the NF-κB signaling pathway, which promotes airway mucus hypersecretion. This study identifies one of the mechanisms regulating airway mucus secretion and provides a new potential target for its prevention and treatment.

Effects of co-application of tiotropium bromide and traditional Chinese medicine on patients with stable chronic obstructive pulmonary disease: a muilticenter, randomized, controlled trial study

Background

Chronic Obstructive Pulmonary Disease (COPD) is a common, preventable, and treatable disease. Traditional Chinese Medicine (TCM) has shown promising potential in COPD treatment. and we conducted a multi-center RCT to evaluate the effectiveness of TCM-based therapy in stable COPD patients.

Methods

In this multicenter, double-blind RCT, a total of 200 patients were supposed to be assigned to either trial or control group randomly. Both groups received Tiotropium (18 μg) from month 0 to month 12. Trial group received additional TCM granules, while control group received a placebo from month 0 to month 6. Symptom assessment, total effective rate, lung function measurements, hospitalization rates, and quality of life were evaluated at month 0, month 6, and month 12. Adverse events were assessed at month 12.

Results

Of the initial 105 patients (aged 40-80) who completed the study, 51 were in trial group and 54 were in control group. At month 6, significant differences were observed between two groups in total effective rate (p = 0.020), sputum score (p = 0.047), changes in FVC% (p = 0.047) and FEV1 (p = 0.046). At month 12, significant differences were observed in sputum score (p = 0.020), FVC (p = 0.042), and change in FEV1 (p = 0.013). Compared to baseline, they both demonstrated improvements in symptoms, acute exacerbation, lung function, quality of life, and exercise tolerance.

Conclusion

TCM treatment effectively improved total effective rate, sputum symptom, FVC%, FEV1, and exhibited prolonged efficacy in improving sputum symptoms and FEV1 in stable COPD patients.Clinical trial registration:https://www.chictr.org.cn/showproj.html?proj=6029 identifier ChiCTR-TRC-13003531.

Quorum-sensing regulation of phenazine production heightens Pseudomonas aeruginosa resistance to ciprofloxacin

Quorum sensing is a type of cell-cell communication that modulates various biological activities of bacteria. Previous studies indicate that quorum sensing contributes to the evolution of bacterial resistance to antibiotics, but the underlying mechanisms are not fully understood. In this study, we grew Pseudomonas aeruginosa in the presence of sub-lethal concentrations of ciprofloxacin, resulting in a large increase in ciprofloxacin minimal inhibitory concentration. We discovered that quorum sensing-mediated phenazine biosynthesis was significantly enhanced in the resistant isolates, where the quinolone circuit was the predominant contributor to this phenomenon. We found that production of pyocyanin changed carbon flux and showed that the effect can be partially inhibited by the addition of pyruvate to cultures. This study illustrates the role of quorum sensing-mediated phenotypic resistance and suggests a strategy for its prevention.

[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.

Chronic obstructive pulmonary disease and the airway microbiome: A review for clinicians

Chronic obstructive pulmonary disease (COPD) is a complex heterogeneous disease characterized by progressive airflow limitation and chronic inflammation. The progressive development and long-term repeated acute exacerbation of COPD make many patients still unable to control the deterioration of the disease after active treatment, and even eventually lead to death. An increasing number of studies have shown that the occurrence and development of COPD are closely related to the composition and changes of airway microbiome. This article reviews the interaction between COPD and airway microbiome, the potential mechanisms of interaction, and the treatment methods related to microbiome. We elaborated the internal correlation between airway microbiome and different stages of COPD, inflammatory endotypes, glucocorticoid and antibiotic treatment, analyze the pathophysiological mechanisms such as the "vicious cycle" hypothesis, abnormal inflammation-immune response of the host and the "natural selection" of COPD to airway microbiome, introduce the treatment of COPD related to microbiome and emphasize the predictive value of airway microbiome for the progression, exacerbation and prognosis of COPD, as well as the guiding role for clinical management of patients, in order to provide a new perspective for exploring the pathogenesis of COPD, and also provide clues and guidance for finding new treatment targets.

An integrated metabo-lipidomics profile of induced sputum for the identification of novel biomarkers in the differential diagnosis of asthma and COPD

BACKGROUND

Due to their complexity and to the presence of common clinical features, differentiation between asthma and chronic obstructive pulmonary disease (COPD) can be a challenging task, complicated in such cases also by asthma-COPD overlap syndrome. The distinct immune/inflammatory and structural substrates of COPD and asthma are responsible for significant differences in the responses to standard pharmacologic treatments. Therefore, an accurate diagnosis is of central relevance to assure the appropriate therapeutic intervention in order to achieve safe and effective patient care. Induced sputum (IS) accurately mirrors inflammation in the airways, providing a more direct picture of lung cell metabolism in comparison to those specimen that reflect analytes in the systemic circulation.

METHODS

An integrated untargeted metabolomics and lipidomics analysis was performed in IS of asthmatic (n = 15) and COPD (n = 22) patients based on Ultra-High-Pressure Liquid Chromatography-Mass Spectrometry (UHPLC-MS) and UHPLC-tandem MS (UHPLC-MS/MS). Partial Least Squares-Discriminant Analysis (PLS-DA) was applied to resulting dataset. The analysis of main enriched metabolic pathways and the association of the preliminary metabolites/lipids pattern identified to clinical parameters of asthma/COPD differentiation were explored. Multivariate ROC analysis was performed in order to determine the discriminatory power and the reliability of the putative biomarkers for diagnosis between COPD and asthma.

RESULTS

PLS-DA indicated a clear separation between COPD and asthmatic patients. Among the 15 selected candidate biomarkers based on Variable Importance in Projection scores, putrescine showed the highest score. A differential IS bio-signature of 22 metabolites and lipids was found, which showed statistically significant variations between asthma and COPD. Of these 22 compounds, 18 were decreased and 4 increased in COPD compared to asthmatic patients. The IS levels of Phosphatidylethanolamine (PE) (34:1), Phosphatidylglycerol (PG) (18:1;18:2) and spermine were significantly higher in asthmatic subjects compared to COPD.

CONCLUSIONS

This is the first pilot study to analyse the IS metabolomics/lipidomics signatures relevant in discriminating asthma vs COPD. The role of polyamines, of 6-Hydroxykynurenic acid and of D-rhamnose as well as of other important players related to the alteration of glycerophospholipid, aminoacid/biotin and energy metabolism provided the construction of a diagnostic model that, if validated on a larger prospective cohort, might be used to rapidly and accurately discriminate asthma from COPD.

Impact of CFTR Modulation on Pseudomonas aeruginosa Infection in People With Cystic Fibrosis

BACKGROUND

Pseudomonas aeruginosa is a multidrug-resistant pathogen causing recalcitrant pulmonary infections in people with cystic fibrosis (pwCF). Cystic fibrosis transmembrane conductance regulator (CFTR) modulators have been developed that partially correct the defective chloride channel driving disease. Despite the many clinical benefits, studies in adults have demonstrated that while P. aeruginosa sputum load decreases, chronic infection persists. Here, we investigate how P. aeruginosa in pwCF may change in the altered lung environment after CFTR modulation.

METHODS

P. aeruginosa strains (n = 105) were isolated from the sputum of 11 chronically colonized pwCF at baseline and up to 21 months posttreatment with elexacaftor-tezacaftor-ivacaftor or tezacaftor-ivacaftor. Phenotypic characterization and comparative genomics were performed.

RESULTS

Clonal lineages of P. aeruginosa persisted after therapy, with no evidence of displacement by alternative strains. We identified commonly mutated genes among patient isolates that may be positively selected for in the CFTR-modulated lung. However, classic chronic P. aeruginosa phenotypes such as mucoid morphology were sustained, and isolates remained just as resistant to clinically relevant antibiotics.

CONCLUSIONS

Despite the clinical benefits of CFTR modulators, clonal lineages of P. aeruginosa persist that may prove just as difficult to manage in the future, especially in pwCF with advanced lung disease.

Synergistic effects of COVID-19 and Pseudomonas aeruginosa in chronic obstructive pulmonary disease: a polymicrobial perspective

This article discusses the connection between the novel coronavirus disease 2019 (COVID-19) caused by the coronavirus-2 (SARS-CoV-2) and chronic obstructive pulmonary disease (COPD). COPD is a multifaceted respiratory illness that is typically observed in individuals with chronic exposure to chemical irritants or severe lung damage caused by various pathogens, including SARS-CoV-2 and Pseudomonas aeruginosa. The pathogenesis of COPD is complex, involving a variety of genotypes and phenotypic characteristics that result in severe co-infections and a poor prognosis if not properly managed. We focus on the role of SARS-CoV-2 infection in severe COPD exacerbations in connection to P.  aeruginosa infection, covering pathogenesis, diagnosis, and therapy. This review also includes a thorough structural overview of COPD and recent developments in understanding its complicated and chronic nature. While COVID-19 is clearly linked to emphysema and chronic bronchitis at different stages of the disease, our understanding of the precise interaction between microbial infections during COPD, particularly with SARS-CoV-2 in the lungs, remains inadequate. Therefore, it is crucial to understand the host-pathogen relationship from the clinician's perspective in order to effectively manage COPD. This article aims to provide a comprehensive overview of the subject matter to assist clinicians in their efforts to improve the treatment and management of COPD, especially in light of the COVID-19 pandemic.

Comparative analysis of antibiotic susceptibility patterns and clinical features of mucoid and non-mucoid Pseudomonas aeruginosa infections: a retrospective study

Background

Pseudomonas aeruginosa (PA) is a prevalent opportunistic pathogen that has close associations with both acute and chronic infections. However, there exists an insufficiency of accurate and comprehensive data pertaining to the antimicrobial susceptibility patterns and clinical characteristics of both mucoid and non-mucoid strains of PA (mPA and non-mPA, respectively).

Methods

From January 1, 2021 to December 31, 2022, a thorough retrospective study was carried out to examine and compare the antibiotic susceptibility test outcomes and clinical characteristics of hospitalized patients with mPA and non-mPA infections.

Results

This study investigated a cohort of 111 patients who were diagnosed with mPA infections, as well as 792 patients diagnosed with non-mPA infections. Significant demographic disparities, including gender (p < 0.001), age (p < 0.001), length of hospital stay (p < 0.001), diabetes (p = 0.043), and hypertension (p < 0.001), are evident between the mPA and non-mPA groups. The mPA group commonly necessitates hospitalization for respiratory system diseases, whereas the non-mPA group is associated with concomitant cardiovascular and cerebrovascular diseases. The mPA group demonstrates lower utilization rates of medical devices, such as Foley catheter (p < 0.001), nasogastric tube (p < 0.001), mechanical ventilation (p < 0.001), tracheostomy (p < 0.001), arterial and venous catheterization (p < 0.001), and exhibits superior organ function status, including lower incidences of hypoalbuminemia (p < 0.001), septic shock (p < 0.001), liver dysfunction (p < 0.001), renal failure (p < 0.001), and respiratory failure (p < 0.001). The non-mPA group is more vulnerable to infection with two or more bacterial pathogens compared to the mPA group, with the non-mPA group frequently resulting in Enterobacteriaceae infections and the mPA group being associated with fungal infections. Variations in antibiotic sensitivity are noted for Amikacin (p < 0.001), Ciprofloxacin (p < 0.001), Cefepime (p = 0.003), and Levofloxacin (p < 0.001) in antibiotic susceptibility testing, with resistance patterns closely tied to specific antibiotic usage.

Conclusion

There are significant demographic characteristics, clinical manifestations and antibiotic susceptibility between mPA and non-mPA infections. It is crucial to emphasize these characteristics due to their significant role in preventing and treating PA infections.

Secondary messenger signalling influences Pseudomonas aeruginosa adaptation to sinus and lung environments

Pseudomonas aeruginosa is a cause of chronic respiratory tract infections in people with cystic fibrosis (CF), non-CF bronchiectasis, and chronic obstructive pulmonary disease. Prolonged infection allows the accumulation of mutations and horizontal gene transfer, increasing the likelihood of adaptive phenotypic traits. Adaptation is proposed to arise first in bacterial populations colonizing upper airway environments. Here, we model this process using an experimental evolution approach. Pseudomonas aeruginosa PAO1, which is not airway adapted, was serially passaged, separately, in media chemically reflective of upper or lower airway environments. To explore whether the CF environment selects for unique traits, we separately passaged PAO1 in airway-mimicking media with or without CF-specific factors. Our findings demonstrated that all airway environments-sinus and lungs, under CF and non-CF conditions-selected for loss of twitching motility, increased resistance to multiple antibiotic classes, and a hyper-biofilm phenotype. These traits conferred increased airway colonization potential in an in vivo model. CF-like conditions exerted stronger selective pressures, leading to emergence of more pronounced phenotypes. Loss of twitching was associated with mutations in type IV pili genes. Type IV pili mediate surface attachment, twitching, and induction of cAMP signalling. We additionally identified multiple evolutionary routes to increased biofilm formation involving regulation of cyclic-di-GMP signalling. These included the loss of function mutations in bifA and dipA phosphodiesterase genes and activating mutations in the siaA phosphatase. These data highlight that airway environments select for traits associated with sessile lifestyles and suggest upper airway niches support emergence of phenotypes that promote establishment of lung infection.

Mortality and exacerbations associated with Stenotrophomonas maltophilia in chronic obstructive pulmonary disease. A regional cohort study of 22,689 outpatients

OBJECTIVES

The clinical significance of Stenotrophomonas maltophilia in patients with COPD is poorly understood. We aimed to determine whether a lower respiratory tract culture positive for S. maltophilia in COPD patients was independently associated with increased risk of death and hospitalisation for exacerbation of COPD.

METHODS

An observational cohort study following outpatients with COPD in Eastern Denmark between 2010 and 2018, with a follow-up period of five years. Presence of S. maltophilia was treated as a time-varying exposure, where patients were considered exposed at the time of the first isolation of S. maltophilia from the lower respiratory tract. The hazard ratio (HR) of death and hospitalisation for acute exacerbations of COPD was assessed using a Cox proportional hazards regression.

RESULTS

Of the total 22,689 patients 459 (2.0%) had a lower respiratory sample positive for S. maltophilia. A total of 7,649 deaths (S. maltophilia positive: 243 (52.9%) and S. maltophilia negative: 7,406 (34.4%)) and 24,912 hospitalisations for exacerbation of COPD (S. maltophilia positive: 1,100 in 459 patients and S. maltophilia negative: 23,821 in 22,230 patients) were registered during the study period. We found that a lower respiratory tract culture positive for S. maltophilia was associated with both increased mortality: HR 3.3 (95% CI 2.6-4.3), and hospitalisation for exacerbation of COPD: HR 3.4 (95% CI 2.8-4.1).

CONCLUSIONS

A lower respiratory tract culture positive for S. maltophilia in COPD patients was associated with a substantially increased mortality and hospitalisation for exacerbation of COPD. Randomised controlled trials are proposed to determine whether S. maltophilia should be the target of antibiotic treatment.

Periodontopathogens Porphyromonas gingivalis and Fusobacterium nucleatum and Their Roles in the Progression of Respiratory Diseases

The intricate interplay between oral microbiota and the human host extends beyond the confines of the oral cavity, profoundly impacting the general health status. Both periodontal diseases and respiratory diseases show high prevalence worldwide and have a marked influence on the quality of life for the patients. Accumulating studies are establishing a compelling association between periodontal diseases and respiratory diseases. Here, in this review, we specifically focus on the key periodontal pathogenic bacteria Porphyromonas gingivalis and Fusobacterium nucleatum and dissect their roles in the onset and course of respiratory diseases, mainly pneumonia, chronic obstructive pulmonary disease, lung cancer, and asthma. The mechanistic underpinnings and molecular processes on how P. gingivalis and F. nucleatum contribute to the progression of related respiratory diseases are further summarized and analyzed, including: induction of mucus hypersecretion and chronic airway inflammation; cytotoxic effects to disrupt the morphology and function of respiratory epithelial cells; synergistic pathogenic effects with respiratory pathogens like Streptococcus pneumoniae and Pseudomonas aeruginosa. By delving into the complex relationship to periodontal diseases and periodontopathogens, this review helps unearth novel insights into the etiopathogenesis of respiratory diseases and inspires the development of potential therapeutic avenues and preventive strategies.

Stability Considerations for Bacteriophages in Liquid Formulations Designed for Nebulization

Pulmonary bacterial infections present a significant health risk to those with chronic respiratory diseases (CRDs) including cystic fibrosis (CF) and chronic-obstructive pulmonary disease (COPD). With the emergence of antimicrobial resistance (AMR), novel therapeutics are desperately needed to combat the emergence of resistant superbugs. Phage therapy is one possible alternative or adjunct to current antibiotics with activity against antimicrobial-resistant pathogens. How phages are administered will depend on the site of infection. For respiratory infections, a number of factors must be considered to deliver active phages to sites deep within the lung. The inhalation of phages via nebulization is a promising method of delivery to distal lung sites; however, it has been shown to result in a loss of phage viability. Although preliminary studies have assessed the use of nebulization for phage therapy both in vitro and in vivo, the factors that determine phage stability during nebulized delivery have yet to be characterized. This review summarizes current findings on the formulation and stability of liquid phage formulations designed for nebulization, providing insights to maximize phage stability and bactericidal activity via this delivery method.

Rapid detection of Pseudomonas aeruginosa by recombinase polymerase amplification combined with CRISPR-Cas12a biosensing system

Pseudomonas aeruginosa (P. aeruginosa) is an important bacterial pathogen involved in a wide range of infections and antimicrobial resistance. Rapid and reliable diagnostic methods are of vital important for early identification, treatment, and stop of P. aeruginosa infections. In this study, we developed a simple, rapid, sensitive, and specific detection platform for P. aeruginosa infection diagnosis. The method integrated recombinase polymerase amplification (RPA) technique with clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein 12a (Cas12a) biosensing system and was termed P. aeruginosa-CRISPR-RPA assay. The P. aeruginosa-CRISPR-RPA assay was subject to optimization of reaction conditions and evaluation of sensitivity, specificity, and clinical feasibility with the serial dilutions of P. aeruginosa genomic DNA, the non-P. aeruginosa strains, and the clinical samples. As a result, the P. aeruginosa-CRISPR-RPA assay was able to complete P. aeruginosa detection within half an hour, including RPA reaction at 42°C for 20 min and CRISPR-Cas12a detection at 37°C for 10 min. The diagnostic method exhibited high sensitivity (60 fg per reaction, ~8 copies) and specificity (100%). The results of the clinical samples by P. aeruginosa-CRISPR-RPA assay were consistent to that of the initial result by microfluidic chip method. These data demonstrated that the newly developed P. aeruginosa-CRISPR-RPA assay was reliable for P. aeruginosa detection. In summary, the P. aeruginosa-CRISPR-RPA assay is a promising tool to early and rapid diagnose P. aeruginosa infection and stop its wide spread especially in the hospital settings.

Bacterial load and related innate immune response in the bronchi of rapid decliners with chronic obstructive pulmonary disease

BACKGROUND

Characterization of COPD patients with rapid lung functional decline is of interest for prognostic and therapeutic reasons. We recently reported an impaired humoral immune response in rapid decliners.

OBJECTIVE

To determine the microbiota associated to markers of innate immune host response in COPD patients with rapid lung functional decline.

METHODS

In COPD patients monitored for at least 3 years (mean ± SD: 5.8 ± 3 years) for lung functional decline, the microbiota and related markers of immune response was measured in bronchial biopsies of patients with different lung functional decline (rate of FEV1% lung functional decline: no decline FEV1%, ≤20 ml/year n = 21, slow decline FEV1%, >20 ≤ 70 ml/year, n = 14 and rapid decline FEV1%, >70 ml/year, n = 15) using qPCR for microbiota and immunohistochemistry for cell-receptors and inflammatory markers.

MAIN RESULTS

Pseudomonas aeruginosa and Streptococcus pneumoniae were increased in rapid decliners vs slow decliners, S. pneumoniae was also increased compared to non decliners. In all patients, S. pneumoniae (copies/ml) positively correlated with pack-years consumption, lung function decline, TLR4, NOD1, NOD2 scored in bronchial epithelium and NOD1/mm² in lamina propria.

CONCLUSION

These data show an imbalance of microbiota components in rapid decliners which is associated to the expression of the related cell-receptors in all COPD patients. These findings may help in the prognostic stratification and treatment of patients.

COPD Exacerbation-Related Pathogens and Previous COPD Treatment

We evaluated whether the pathogens identified during acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) are associated with the COPD medications used in the 6 months before AE-COPD. We collected the medical records of patients diagnosed with AE-COPD at 28 hospitals between January 2008 and December 2019 and retrospectively analyzed them. Microorganisms identified at the time of AE-COPD were analyzed according to the use of inhaled corticosteroid (ICS) and systemic steroid after adjusting for COPD severity. We evaluated 1177 patients with AE-COPD and available medication history. The mean age of the patients was 73.9 ± 9.2 years, and 83% were males. The most frequently identified bacteria during AE-COPD were Pseudomonas aeruginosa (10%), followed by Mycoplasma pneumoniae (9.4%), and Streptococcus pneumoniae (5.1%), whereas the most commonly identified viruses were rhinovirus (11%) and influenza A (11%). During AE-COPD, bacteria were more frequently identified in the ICS than non-ICS group (p = 0.009), and in the systemic steroid than non-systemic steroid group (p < 0.001). In patients who used systemic steroids before AE-COPD, the risk of detecting Pseudomonas aeruginosa was significantly higher during AE-COPD (OR 1.619, CI 1.007−2.603, p = 0.047), but ICS use did not increase the risk of Pseudomonas detection. The risk of respiratory syncytial virus (RSV) detection was low when ICS was used (OR 0.492, CI 0.244−0.988, p = 0.045). COPD patients who used ICS had a lower rate of RSV infection and similar rate of P. aeruginosa infection during AE-COPD compared to patients who did not use ICS. However, COPD patients who used systemic steroids within 6 months before AE-COPD had an increased risk of P. aeruginosa infection. Therefore, anti-pseudomonal antibiotics should be considered in patients with AE-COPD who have used systemic steroids.

A novel structurally identified epitope delivered by macrophage membrane-coated PLGA nanoparticles elicits protection against Pseudomonas aeruginosa

The increasing prevalence of antibiotic resistance by Pseudomonas aeruginosa (PA) raises an urgent need for an effective vaccine. The outer membrane proteins of PA, especially those that are upregulated during infection, are ideal vaccine targets. However, the strong hydrophobicity of these proteins hinders their application for this purpose. In this study, we selected eight outer membrane proteins from PA with the most significantly upregulated expression. Their extracellular loops were analyzed and screened by using sera from patients who had recovered from PA infection. As a result, a novel immunogenic epitope (Ep_167-193) from PilY1 (PA4554) was found. Moreover, we constructed a macrophage membrane-coated PLGA (poly lactic-co-glycolic acid) nanoparticle vaccine carrying PilY1 Ep_167-193 (PNPs@M-Ep_167-193) that elicits a Th2 immune response and confers adequate protection in mice. Our data furnished the promising vaccine candidate PNPs@M-Ep_167-193 while providing additional evidence for structure-based epitope identification and vaccine design.

Bacteriophage: A new therapeutic player to combat neutrophilic inflammation in chronic airway diseases

Persistent respiratory bacterial infections are a clinical burden in several chronic inflammatory airway diseases and are often associated with neutrophil infiltration into the lungs. Following recruitment, dysregulated neutrophil effector functions such as increased granule release and formation of neutrophil extracellular traps (NETs) result in damage to airway tissue, contributing to the progression of lung disease. Bacterial pathogens are a major driver of airway neutrophilic inflammation, but traditional management of infections with antibiotic therapy is becoming less effective as rates of antimicrobial resistance rise. Bacteriophages (phages) are now frequently identified as antimicrobial alternatives for antimicrobial resistant (AMR) airway infections. Despite growing recognition of their bactericidal function, less is known about how phages influence activity of neutrophils recruited to sites of bacterial infection in the lungs. In this review, we summarize current in vitro and in vivo findings on the effects of phage therapy on neutrophils and their inflammatory mediators, as well as mechanisms of phage-neutrophil interactions. Understanding these effects provides further validation of their safe use in humans, but also identifies phages as a targeted neutrophil-modulating therapeutic for inflammatory airway conditions.

Chronic Bronchial Infection Is Associated with More Rapid Lung Function Decline in Chronic Obstructive Pulmonary Disease

Rationale: Some patients with chronic obstructive pulmonary disease (COPD) suffer accelerated lung function (forced expiratory volume in 1 second [FEV₁]) decline over time. Objectives: To investigate the relationship between chronic bronchial infection (CBI) and, in particular, the isolation of Pseudomonas aeruginosa (PA), and FEV₁ decline in COPD. Methods: Post-hoc analysis of a prospective cohort of 201 patients with COPD followed up every 3-6 months for 84 months. CBI was defined as ⩾3 sputum positive cultures of the same pathogenic micro-organism (PPM) over 1 year. Patients were stratified according to the presence of CBI by any PPM, as well by a single or multiple isolation of PA during follow-up. An adjusted mixed-effects linear regression model was used to investigate the independent effects of CBI and PA isolation on FEV₁ decline over time. Results: During follow-up, PPMs were never isolated in 43.3% of patients, in 23.9% of them PPMs were isolated once, and CBI by any PPM was confirmed in 32.8% of participants. FEV₁ decline in the entire cohort was 33.7 (95% confidence interval [CI], 21.4-46.1) ml/year. This was significantly increased in patients with CBI by any PPM (57.1 [95% CI, 28.5-79.3] ml/year) and in those in whom PA was isolated at least once (48.5 [95% CI, 27.3-88.2] ml/year). Multivariable analysis showed that the presence of both CBI by any PPM, and at least one PA isolation, were independent factors associated with faster FEV₁ decline adjusted by baseline FEV₁, presence of bronchiectasis, body mass index, age, exacerbations, smoking status, symptoms, baseline treatment, and comorbidities. Conclusions: The presence of CBI by any PPM, and one or more PA isolation, were independently associated with FEV₁ decline in patients with COPD.

Prognostic risk factors for moderate-to-severe exacerbations in patients with chronic obstructive pulmonary disease: a systematic literature review

Background

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. COPD exacerbations are associated with a worsening of lung function, increased disease burden, and mortality, and, therefore, preventing their occurrence is an important goal of COPD management. This review was conducted to identify the evidence base regarding risk factors and predictors of moderate-to-severe exacerbations in patients with COPD.

Methods

A literature review was performed in Embase, MEDLINE, MEDLINE In-Process, and the Cochrane Central Register of Controlled Trials (CENTRAL). Searches were conducted from January 2015 to July 2019. Eligible publications were peer-reviewed journal articles, published in English, that reported risk factors or predictors for the occurrence of moderate-to-severe exacerbations in adults age ≥ 40 years with a diagnosis of COPD.

Results

The literature review identified 5112 references, of which 113 publications (reporting results for 76 studies) met the eligibility criteria and were included in the review. Among the 76 studies included, 61 were observational and 15 were randomized controlled clinical trials. Exacerbation history was the strongest predictor of future exacerbations, with 34 studies reporting a significant association between history of exacerbations and risk of future moderate or severe exacerbations. Other significant risk factors identified in multiple studies included disease severity or bronchodilator reversibility (39 studies), comorbidities (34 studies), higher symptom burden (17 studies), and higher blood eosinophil count (16 studies).

Conclusions

This systematic literature review identified several demographic and clinical characteristics that predict the future risk of COPD exacerbations. Prior exacerbation history was confirmed as the most important predictor of future exacerbations. These prognostic factors may help clinicians identify patients at high risk of exacerbations, which are a major driver of the global burden of COPD, including morbidity and mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02123-5.

Preclinical Evaluation of Recombinant Microbial Glycoside Hydrolases as Antibiofilm Agents in Acute Pulmonary Pseudomonas aeruginosa Infection

The bacterium Pseudomonas aeruginosa can colonize the airways of patients with chronic lung disease. Within the lung, P. aeruginosa forms biofilms that can enhance resistance to antibiotics and immune defenses. P. aeruginosa biofilm formation is dependent on the secretion of matrix exopolysaccharides, including Pel and Psl. In this study, recombinant glycoside hydrolases (GHs) that degrade Pel and Psl were evaluated alone and in combination with antibiotics in a mouse model of P. aeruginosa infection. Intratracheal GH administration was well tolerated by mice. Pharmacokinetic analysis revealed that, although GHs have short half-lives, administration of two GHs in combination resulted in increased GH persistence. Combining GH prophylaxis and treatment with the antibiotic ciprofloxacin resulted in greater reduction in pulmonary bacterial burden than that with either agent alone. This study lays the foundation for further exploration of GH therapy in bacterial infections.

Endotyping Chronic Obstructive Pulmonary Disease, Bronchiectasis, and the "Chronic Obstructive Pulmonary Disease-Bronchiectasis Association"

Rationale: Bronchiectasis and chronic obstructive pulmonary disease (COPD) are two disease entities with overlapped clinical features, and codiagnosis frequently occurs (termed the "COPD-bronchiectasis association"). Objectives: To investigate the sputum microbiome and proteome in patients with bronchiectasis, COPD, and the COPD-bronchiectasis association with the aim of identifying endotypes that may inform treatment. Methods: Sputum microbiome and protein profiling were carried out using 16S rRNA amplicon sequencing and a label-free proteomics workflow, respectively, in a cohort comprising patients with COPD (n = 43), bronchiectasis (n = 30), and the COPD-bronchiectasis association (n = 48). Results were validated in an independent cohort of 91 patients (n = 28-31 each group) using targeted measurements of inflammatory markers, mucins, and bacterial culture. Measurements and Main Results: Principal component analysis of sputum microbiome and protein profiles showed a partial separation between the COPD and the "COPD-bronchiectasis association" group. Further analyses revealed that patients with the "COPD-bronchiectasis association" had a higher abundance of proteobacteria, higher expression of mucin-5AC and proteins from the "neutrophil degranulation" pathway compared to those with COPD. In contrast, patients with COPD had an elevated expression of mucin-5B and several peptidase inhibitors, higher abundance of common commensal taxa, and a greater microbiome diversity. The profiles of "COPD-bronchiectasis association" and bronchiectasis groups were largely overlapping. Five endotypes were proposed with differential inflammatory, mucin, and microbiological features. The key features related to the "COPD-bronchiectasis association" were validated in an independent cohort. Conclusions: Neutrophilic inflammation, differential mucin expression, and Gram-negative infection are dominant traits in patients with the "COPD-bronchiectasis association."

The Impact of Nontuberculous Mycobacteria Species on Mortality in Patients With Nontuberculous Mycobacterial Lung Disease

Patients with nontuberculous mycobacterial lung disease (NTM-LD) have increased mortality. The impact of NTM species on the risk of mortality remains unclear, especially that of death by non-cancer causes. We conducted a retrospective cohort study from 2006 to 2018 in a tertiary-care hospital in Taiwan. We enrolled patients who fulfilled the microbiological diagnostic criteria of NTM-LD. The mortality causes within 8 years after diagnosis were identified, and the Cox proportional hazard regression was performed for risk factors of mortality. A total of 1,652 subjects with NTM-LD were included. Among them, 723 (43.8%) were infected by Mycobacterium avium complex (MAC), 408 (24.7%) by M. abscessus complex (MABC), 120 (7.3%) by Mycobacterium kansasii (MK), 304 (18.4%) by other rapid-growing mycobacteria (RGM), and 97 (5.9%) by other slow-growing mycobacteria (SGM) groups. The 8-year all-cause mortality was 45.2% for all and the highest in the MK-LD group (59.2%), followed by the MABC-LD and MAC-LD groups. The adjusted hazard ratios were 2.20 (95% confidence interval: 1.40–3.46) in the MK-LD, 1.85 (1.54–2.22) in the MABC-LD, and 1.65 (1.12–2.41) in the MAC-LD groups for all-cause mortality, compared with the SGM group. Kaplan–Meier survival curves showed that all-cause mortality, non-cancer mortality, and mortality due to chronic airway diseases were significantly correlated with NTM species (log-rank p = 0.0031, < 0.001, and 0.001, respectively). High 8-year mortality rates were found in patients with NTM-LDs according to different NTM species. Notably, the difference was significant in non-cancer mortality causes, especially in chronic airway diseases.

Vaccination and modern management of chronic obstructive pulmonary disease - a narrative review

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) carries a tremendous societal and individual burden, posing significant challenges for public health systems worldwide due to its high morbidity and mortality. Due to aging and multimorbidity but also in the wake of important progress in deciphering the heterogeneous disease endotypes, an individualized approach to the prevention and management of COPD is necessary.

AREAS COVERED

This article tackles relevant immunization strategies that are available or still under development with a focus on the latest evidence but also controversies around different regional immunization approaches. Further, we present the crossover between chronic lung inflammation and lung microbiome disturbance as well as its role in delineating COPD endotypes. Moreover, the article attempts to underline endotype-specific treatment approaches. Lastly, we highlight non-pharmacologic prevention and management programs in view of the challenges and opportunities of the COVID-19 era.

EXPERT OPINION

Despite the remaining challenges, personalized medicine has the potential to offer tailored approaches to prevention and therapy and promises to improve the care of patients living with COPD.

Use of inhaled corticosteroids and risk of acquiring Pseudomonas aeruginosa in patients with chronic obstructive pulmonary disease

BACKGROUND

Inhaled corticosteroids (ICS) are commonly used to treat COPD and are associated with increased risk of pneumonia. The aim of this study was to assess if accumulated use of ICS is associated with a dose-dependent risk of a positive airway culture with Pseudomonas aeruginosa in patients with COPD.

METHODS

We conducted a multiregional epidemiological cohort study including Danish COPD patients followed in outpatient clinics during 2010-2017. ICS use was categorised based on accumulated prescriptions redeemed 365 days prior to cohort entry. Cox proportional hazard regression model was used to estimate the risk of acquiring P. aeruginosa. Propensity score matched models were used as sensitivity analyses.

RESULTS

A total of 21 408 patients were included in the study, of which 763 (3.6%) acquired P. aeruginosa during follow-up. ICS use was associated with a dose-dependent risk of P. aeruginosa (low ICS dose: HR 1.38, 95% CI 1.03 to 1.84, p=0.03; moderate ICS dose: HR 2.16, 95% CI 1.63 to 2.85, p<0.0001; high ICS dose: HR 3.58, 95% CI 2.75 to 4.65, p<0.0001; reference: no ICS use). A propensity matched model confirmed the results (high ICS dose compared with no/low/moderate ICS dose: HR 2.05, 95% CI 1.76 to 2.39, p p<0.0001).

CONCLUSION

Use of ICS in patients with COPD followed in Danish outpatient clinics was associated with a substantially increased and dose-dependent risk of acquiring P. aeruginosa. Caution should be taken when administering high doses of ICS in severely ill patients with COPD. These results should be confirmed in comparable cohorts and other settings.

Derivation and Validation of a Clinical Prediction Score to Identify the Isolation of Pseudomonas in Pneumonia

Given the focus of existing clinical prediction scores on identifying drug-resistant pathogens as a whole, the application to individual pathogens and other institutions may yield weaker performance. This study aimed to develop a locally derived clinical prediction model for Pseudomonas-mediated pneumonia. This retrospective study included patients ≥18 years of age who were admitted to an academic medical center between 1 July 2010 and 31 July 2020 with a CDC National Healthcare Safety Network confirmed pneumonia diagnosis and were receiving antimicrobials during the index encounter, with a positive respiratory culture. Cystic fibrosis patients were excluded. Logistic regression analysis identified risk factors associated with the isolation of Pseudomonas aeruginosa from respiratory cultures within the derivation cohort (n = 186), which were weighted to generate a prediction score that was applied to the derivation and internal validation (n = 95) cohorts. A total of 281 patients met the inclusion criteria. Five predictor variables were identified, namely, tracheostomy status (4 points), chronic obstructive pulmonary disease (5 points), enteral nutrition (9 points), chronic steroid use (11 points), and Pseudomonas aeruginosa isolation from any culture in the prior 6 months (14 points). At a score of >11, the prediction score demonstrated a sensitivity of 52.4% (95% confidence interval [CI], 36.4 to 68.0%) and a specificity of 84.9% (95% CI, 72.4 to 93.35%) in the validation cohort. Score accuracy was 70.5% (95% CI, 60.3 to 79.4%), and the area under the receiver operating characteristic curve (AUROC) was 0.77 (95% CI, 0.68 to 0.87) in the validation cohort. A prediction score for identifying Pseudomonas aeruginosa in pneumonia was derived, which may have the potential to decrease the use of broad-spectrum antibiotics. Validation with larger and external cohorts is necessary.

IMPORTANCE In this study, we aimed to develop a locally derived clinical prediction model for Pseudomonas-mediated pneumonia. Utilizing a locally validated prediction score may help direct therapeutic management and be generalizable to other clinical settings and similar populations for the selection of appropriate antimicrobial coverage when data are lacking. Our study highlights a unique patient population, including immunocompromised, structural lung disease, and transplant patients. Five predictor variables were identified, namely, tracheostomy status, chronic obstructive pulmonary disease, enteral nutrition, chronic steroid use, and Pseudomonas aeruginosa isolation from any culture in the prior 6 months. A prediction score for identifying Pseudomonas aeruginosa in pneumonia was derived, which may have the potential to decrease the use of broad-spectrum antibiotics, although validation with larger and external cohorts is necessary.

An observational study of Pseudomonas aeruginosa in adult long-term ventilation

Introduction

Pseudomonas aeruginosa increases morbidity and mortality in respiratory disease. To date the long-term ventilation population does not have clear guidelines regarding its management.

Method

We undertook a retrospective observational study in a regional long-term ventilation population (837 patients). We defined the primary outcome as P. aeruginosa isolation. In addition positive cultures for copathogens (Serratia, Proteus species, Stenotrophomonas, Burkholderia cepacia complex and nontuberculous mycobacteria) were recorded. Logistic regression and odds ratios were calculated.

Results

17.6% of the cohort isolated P. aeruginosa, and this pathogen was cultured more frequently in patients with a tracheostomy (logistic regression coefficient 2.90, p≤0.0001) and cystic fibrosis/bronchiectasis (logistic regression coefficient 2.48, p≤0.0001). 6.3% of patients were ventilated via tracheostomy. In the P. aeruginosa positive cohort 46.9% of patients were treated with a long-term macrolide, 36.7% received a nebulised antibiotic and 21.1% received both. Tracheostomised P. aeruginosa positive patients received a nebulised antibiotic more frequently (OR 2.63, 95% CI 1.23–5.64, p=0.013). Copathogens were isolated in 33.3% of the P. aeruginosa cohort. In this cohort patients with a tracheostomy grew a copathogen more frequently than those without (OR 2.75, 95% CI 1.28–5.90).

Conclusions

P. aeruginosa isolation is common within the adult long-term ventilation population and is significantly associated with tracheostomy, cystic fibrosis and bronchiectasis. Further research and international guidelines are needed to establish the prognostic impact of P. aeruginosa and to guide on antimicrobial management. The increased risk of P. aeruginosa should be considered when contemplating long-term ventilation via tracheostomy.

Pseudomonas aeruginosa isolation is common (17%) in long-term ventilated adults and significantly associated with tracheostomy, cystic fibrosis and bronchiectasis. Tracheostomy patients with P. aeruginosa isolates culture copathogens more frequently.https://bit.ly/3vvxBbB

Microbiome Modulation as a Novel Strategy to Treat and Prevent Respiratory Infections

Acute and chronic lower airway disease still represent a major cause of morbidity and mortality on a global scale. With the steady rise of multidrug-resistant respiratory pathogens, such as Pseudomonas aeruginosa and Klebsiella pneumoniae, we are rapidly approaching the advent of a post-antibiotic era. In addition, potentially detrimental novel variants of respiratory viruses continuously emerge with the most prominent recent example being severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To this end, alternative preventive and therapeutic intervention strategies will be critical to combat airway infections in the future. Chronic respiratory diseases are associated with alterations in the lung and gut microbiome, which is thought to contribute to disease progression and increased susceptibility to infection with respiratory pathogens. In this review we will focus on how modulating and harnessing the microbiome may pose a novel strategy to prevent and treat pulmonary infections as well as chronic respiratory disease.

Antimicrobial therapies for prevention of recurrent acute exacerbations of COPD (AECOPD): beyond the guidelines

Background

Unfortunately, many COPD patients continue to exacerbate despite good adherence to GOLD Class D recommended therapy. Acute exacerbations lead to an increase in symptoms, decline in lung function and increased mortality rate. The purpose of this review is to do a literature search for any prophylactic anti-microbial treatment trials in GOLD class D patients who ‘failed’ recommended therapy and discuss the role of COPD phenotypes, lung and gut microbiota and co-morbidities in developing a tailored approach to anti-microbial therapies for high frequency exacerbators.

Main text

There is a paucity of large, well-conducted studies in the published literature to date. Factors such as single-centre, study design, lack of well-defined controls, insufficient patient numbers enrolled and short follow-up periods were significant limiting factors in numerous studies. One placebo-controlled study involving more than 1000 patients, who had 2 or more moderate exacerbations in the previous year, demonstrated a non-significant reduction in exacerbations of 19% with 5 day course of moxifloxacillin repeated at 8 week intervals. In Pseudomonas aeruginosa (Pa) colonised COPD patients, inhaled antimicrobial therapy using tobramycin, colistin and gentamicin resulted in significant reductions in exacerbation frequency. Viruses were found to frequently cause acute exacerbations in COPD (AECOPD), either as the primary infecting agent or as a co-factor. However, other, than the influenza vaccination, there were no trials of anti-viral therapies that resulted in a positive effect on reducing AECOPD. Identifying clinical phenotypes and co-existing conditions that impact on exacerbation frequency and severity is essential to provide individualised treatment with targeted therapies. The role of the lung and gut microbiome is increasingly recognised and identification of pathogenic bacteria will likely play an important role in personalised antimicrobial therapies.

Conclusion

Antimicrobial therapeutic options in patients who continue to exacerbate despite adherence to guidelines-directed therapy are limited. Phenotyping patients, identification of co-existing conditions and assessment of the microbiome is key to individualising antimicrobial therapy. Given the impact of viruses on AECOPD, anti-viral therapeutic agents and targeted anti-viral vaccinations should be the focus of future research studies.

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.

Potential Synergistic Antibiotic Combinations against Fluoroquinolone-Resistant Pseudomonas aeruginosa

The rise in multiple-drug-resistant (MDR) phenotypes in Gram-negative pathogens is a major public health crisis. Pseudomonas aeruginosa is one of the leading causes of nosocomial infections in clinics. Treatment options for P. aeruginosa have become increasingly difficult due tdo its remarkable capacity to resist multiple antibiotics. The presence of intrinsic resistance factors and the ability to quickly adapt to antibiotic monotherapy warrant us to look for alternative strategies like combinatorial antibiotic therapy. Here, we report the frequency of P. aeruginosa multidrug-resistant and extensively drug-resistance (XDR) phenotypes in a super-specialty tertiary care hospital in north India. Approximately 60 percent of all isolated P. aeruginosa strains displayed the MDR phenotype. We found highest antibiotic resistance frequency in the emergency department (EMR), as 20 percent of isolates were resistant to 15 antipseudomonal antibiotics. Presence of plasmids with quinolone-resistance determinants were major drivers for resistance against fluoroquinolone. Additionally, we explored the possible combinatorial therapeutic options with four antipseudomonal antibiotics—colistin, ciprofloxacin, tobramycin, and meropenem. We uncovered an association between different antibiotic interactions. Our data show that the combination of colistin and ciprofloxacin could be an effective combinatorial regimen to treat infections caused by MDR and XDR P. aeruginosa.

Long-Term Risk of Mortality Associated with Isolation of Pseudomonas aeruginosa in COPD: A Systematic Review and Meta-Analysis

Background

Chronic bronchial infection is frequent in chronic obstructive pulmonary disease (COPD), but the impact of the isolation of pathogenic bacteria, and in particular Pseudomonas aeruginosa (PA) in respiratory samples on the prognosis of COPD is unclear.

Methods

We conducted a systematic review of prognostic studies including patients with isolation of PA in sputum in stable state or during exacerbations of COPD. The main outcomes were all-cause mortality, respiratory mortality, and number and severity of future exacerbations. Data were expressed as hazard ratio (HR) (95% confidence interval [CI]) whenever possible.

Results

Of 2773 studies, eight were finally included (23,228 individuals). The mean age ranged from 65.5 to 73 years. Six studies reported data for all-cause mortality. The adjusted risk of death was almost double in patients with PA isolation (HR 1.95, 95% CI, 1.34 to 2.84; quality of evidence moderate). Patients with PA isolation showed a three times higher adjusted risk of readmission at 30 days after discharge (OR 3.60, 95% CI, 3.60 to 12.03, 1 study; quality of evidence very low), and more than double adjusted risk of death and hospitalization at two years (HR 2.80, 95% CI, 2.20 to 3.56, 1 study; quality of evidence very low).

Conclusion

There is moderate certainty that the isolation of PA in sputum is associated with an adjusted increased risk of death in patients with COPD.

Clinico-bacteriological profile and antibiotic resistance pattern in patients with acute exacerbation of COPD

Background

Repeated attacks of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have been attributed to bacterial infections. However, sputum microbiology for identifying the bacteriological profile is not performed usually and remains controversial. Thus, we performed a prospective, cross-sectional study to assess the clinico-bacteriological profile of the patients with AECOPD and antibiotic resistance pattern of bacteria isolated from sputum samples. The study involved 104 consecutive hospitalized patients, of either gender, aged 40–90 years, and diagnosed with AECOPD. Before initiating an empirical antibiotic therapy, the sputum samples of all the patients were collected and subjected to Gram staining, bacterial culture, and antibiotic sensitivity.

Results

The most common bacterial isolates were P. aeruginosa (30.7%) followed by K. pneumoniae (20.3%) and S. pneumoniae (8.6%). Both Gram-positive and Gram-negative bacteria were most sensitive to Meropenem (91%) followed by Amoxicillin-clavulanic acid (83%). However, these bacteria were most resistant to Cefoperazone-sulbactam (43%) followed by Levofloxacin (41%). P. aeruginosa and K. pneumoniae were most resistant to Cefoperazone-sulbactam (23%) followed by Fluoroquinolones (23–35%), while S. pneumoniae was most resistant to Ciprofloxacin (44%) followed by Amoxicillin-clavulanic acid (33%).

Conclusions

Isolation of P. aeruginosa, as the most common agent, further confirms its roles in severe attacks of AECOPD. The regularly used antibiotics were found to be resistant to most isolates, thereby suggesting that severity of AECOPD may be attributed to the prevalence of antibiotic-resistant strains.

The Relationship Between Comorbidities and Microbiologic Findings in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

PURPOSE

Data regarding the relationship between microbiologic features and comorbidities in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) are limited. The aim of this study was to correlate microbiologic findings with comorbidities in patients with moderate to severe AECOPD.

PATIENTS AND METHODS

This multicenter observational study included patients with AECOPD seen at 28 hospitals in South Korea between January 2015 and December 2018, and the data were retrospectively collected. Pathogens were examined in patients with either pulmonary or extrapulmonary comorbidities, and compared to those of patients without comorbidities. The relationship between pathogen type and the number of comorbidities was also evaluated.

RESULTS

Bacterial infections (178 [37.2%] vs 203 [28.7%], p = 0.002) and co-infections with bacteria and viruses (65 [13.6%] vs 57 [8.1%], p = 0.002) were more prevalent in patients with pulmonary comorbidities. Bacterial pathogens (280 [34.7%] vs 101 [26.7%], p=0.006) were detected at a higher rate in patients with extrapulmonary comorbidities. Previous pulmonary tuberculosis (PTB), bronchiectasis, and diabetes mellitus were risk factors for bacterial infection, and congestive heart failure was a risk factor for bacterial and viral co-infection. As the number of comorbidities increased, the risk of bacterial infection increased considerably. Pseudomonas aeruginosa was more frequently identified in patients with previous PTB (57 [15.3%] vs 59 [7.4%], p < 0.001) and bronchiectasis (33 [19.6%] vs 83 [8.3%], p < 0.001).

CONCLUSION

AECOPD patients with comorbidities were more likely to experience infection-related exacerbations compared to those without comorbidities. As the overall number of comorbidities increased, the risk of bacterial infection increased significantly.

Xuanfei Pingchuan Capsules Ameliorate Autophagy in Human Bronchial Epithelial Cells by Inhibiting p38 Phosphorylation

Background: This study aimed to investigate the protective effect of Xuanfei Pingchuan Capsules (XFPC) on autophagy and p38 phosphorylation in human bronchial epithelial (HBE) cells induced by cigarette smoke extract (CSE). Methods: HBE cells were divided into five groups: blank, CSE, low XFPC dose (XFPC-L), medium XFPC dose (XFPC-M), and high XFPC dose (XFPC-H). HBE cells were induced by CSE to establish a cell model for chronic obstructive pulmonary disease, and different doses of XFPC medicated serum were used to treat the cells. The Cell Counting Kit-8 was used to detect cell viability. Flow cytometry was used to detect cell apoptosis. Fluorescence microscopy and the expression level of microtubule-associated protein light chain 3 (LC3)-II in immunohistochemical method were used to observe autophagy in cells. Western blot was used to detect the protein expression level of p38, phospho-p38 (p-p38), LC3-I, LC3-II and Beclin 1. Real-time polymerase chain reaction was used to detect the expression of LC3-I, LC3-II and Beclin 1 on mRNA level. Results: Compared with the blank group, the cell viability of the CSE group was significantly decreased, and apoptosis and the level of autophagy in cells were significantly increased. The mRNA and protein expression of LC3-I, LC3-II, Beclin 1 and the protein level of p-p38 were significantly increased in the CSE-HBE cells. Compared to the CSE group, the different doses of XFPC medicated serum increased cell viability, decreased cell apoptosis, and inhibited mRNA and protein expression of LC3-I, LC3-II, Beclin 1 and protein level of p-p38. These results were especially observed in the group XFPC-H. After adding a p38 agonist, the therapeutic effect of XFPC on cell viability and autophagy was suppressed. Conclusion: XFPC significantly increased cell viability in a CSE-induced HBE cell model for chronic obstructive pulmonary disease through inhibiting the level of autophagy mediated by phosphorylation of p38.

Epigenetic reprogramming of airway macrophages promotes polarization and inflammation in muco-obstructive lung disease

Lung diseases, such as cystic fibrosis and COPD, are characterized by mucus obstruction and chronic airway inflammation, but their mechanistic link remains poorly understood. Here, we focus on the function of the mucostatic airway microenvironment on epigenetic reprogramming of airway macrophages (AM) and resulting transcriptomic and phenotypical changes. Using a mouse model of muco-obstructive lung disease (Scnn1b-transgenic), we identify epigenetically controlled, differentially regulated pathways and transcription factors involved in inflammatory responses and macrophage polarization. Functionally, AMs from Scnn1b-transgenic mice have reduced efferocytosis and phagocytosis, and excessive inflammatory responses upon lipopolysaccharide challenge, mediated through enhanced Irf1 function and expression. Ex vivo stimulation of wild-type AMs with native mucus impairs efferocytosis and phagocytosis capacities. In addition, mucus induces gene expression changes, comparable with those observed in AMs from Scnn1b-transgenic mice. Our data show that mucostasis induces epigenetic reprogramming of AMs, leading to changes favoring tissue damage and disease progression. Targeting these altered AMs may support therapeutic approaches in patients with muco-obstructive lung diseases.

Effectiveness of empirical anti-pseudomonal antibiotics for recurrent COPD exacerbation: a multicenter retrospective cohort study

Although frequent chronic obstructive pulmonary disease (COPD) exacerbation has been associated with the isolation of Pseudomonas aeruginosa (PA) in sputum cultures, it remains unknown whether the empirical use of anti-pseudomonal antibiotics can improve outcomes in patients with frequent COPD exacerbations. This multicenter retrospective cohort study evaluated whether the empirical use of anti-pseudomonal antibiotics improves the length of the hospital stay in patients with recurrent COPD exacerbation (≥ 2 admissions from April 1, 2008 to July 31, 2020). For statistical analysis, a log-linked Gamma model was used. Parameters were estimated using a generalized estimating equation model with an exchangeable correlation structure accounting for repeated observations from a single patient. Covariates included age, body mass index, home oxygen therapy use, respiratory rate, heart rate, oxygen use on admission, mental status, systemic steroid use, activities of daily living, and the number of recurrences. Hospital-specific effects were specified as fixed effects. In total, 344 patients and 965 observations of recurrent COPD exacerbations were selected. Anti-pseudomonal antibiotics were used in 173 patients (18%). The estimated change in the length of the hospital stay between anti-pseudomonal and non-anti-pseudomonal antibiotics groups was 0.039 days [95% confidence interval; - 0.083, 0.162]. Anti-pseudomonal antibiotics could not shorten the length of the hospital stay.

Inhaled corticosteroid dose is associated with Pseudomonas aeruginosa infection in severe COPD

INTRODUCTION

Patients with chronic obstructive pulmonary disease (COPD) with frequent exacerbations (ExCOPD) are commonly treated with inhaled corticosteroids (ICS) and are at risk of infections caused by potential pathogenic bacteria (PPB) including Pseudomonas aeruginosa (PsA).

OBJECTIVES

To investigate the association between the use of ICS and PsA infection among ExCOPD.

METHODS

Case-control study with longitudinal follow-up that recruited ExCOPD after a hospitalisation due to exacerbation between 2012 and 2020. Patients with isolation of PsA (COPD-PsA) in sputum either during admission or follow-up were compared with those with other or no PPB. Clinical, functional characteristics, DDD, use of ICS and survival were evaluated. Cox regression analysis was performed to evaluate the risk factors associated to PsA infection and mortality.

RESULTS

358 patients (78% male, mean age 73±9 years) were enrolled and followed up for a median of 4 years (IQR=3-8). 173 patients (48.3%) had at least a positive culture for PsA. COPD-PsA had more frequent exacerbations, more severe airflow limitation and higher mortality (69.4% vs 46.5%, p<0.001). There were no differences in the use of ICS between groups but the dose of ICS was significantly higher among COPD-PsA (median of 500 µg fluticasone propionate equivalents (IQR=250-1000) vs 400 µg (IQR=200-1000), p=0.007). Blood eosinophil count (BEC) was not different between ICS users and non-users. In multivariate analysis, the dose of ICS was an independent risk factor for PsA infection and mortality but not ICS use.

CONCLUSIONS

ICS dose, but not its use, could be a risk factor for PsA infection in patients with severe COPD regardless of BEC.

Clinical Features and Antimicrobial Susceptibility of Pseudomonas aeruginosa and Acinetobacter baumannii Complex Isolates in Intensive Care Patients with Chronic Obstructive Pulmonary Disease and Community-Acquired Pneumonia in Taiwan

Purpose

Little is known about the features and implications of Pseudomonas aeruginosa (PA) and Acinetobacter baumannii complex (ABC) isolates discovered in patients with chronic obstructive pulmonary disease (COPD) and community-acquired pneumonia (CAP) requiring invasive mechanical ventilation and admission to an intensive care unit. Thus, our study aimed to investigate the clinical characteristics and antimicrobial susceptibilities of PA and ABC isolates cultured from endotracheal aspirates (EAs) in such population.

Patients and Methods

In this retrospective, cross-sectional study, clinical data from medical records were reviewed and collected for analysis.

Results

Of the 262 participants, 17.2% (45/262), 11.5% (30/262), and 27.1% (71/262) had PA, ABC, and any of the two isolates discovered from EA cultures, respectively. Patients with PA isolates were associated with poorer lung function (the Global Initiative for Chronic Obstructive Lung Disease (GOLD) III+IV versus GOLD I+II, odds ratio (OR)=2.39, p= 0.022) and a lower body mass index (per increase of 1 kg/m², OR= 0.93, p= 0.106) while the former was an independent predictor. Moreover, both subjects with ABC isolates and those with any of these two microorganisms were independently associated with a lower serum albumin level (per increase of 1 g/dL, OR= 0.44, p=0.009 and OR= 0.59, p=0.023, respectively). Participants with PA isolates were more likely to have failed weaning (62.2% versus 44.7%, p= 0.048) and death (28.9% versus 12.4%, p= 0.010) than those without PA isolates. The majority of the PA and ABC isolates were susceptible and resistant to all the tested antimicrobials, respectively, except that tigecycline had a reliable activity against ABC.

Conclusion

Our findings provide important information to help intensivists make better treatment decisions in critically ill patients with COPD and CAP.

Animal models of chronic and recurrent Pseudomonas aeruginosa lung infection: significance of macrolide treatment

Animal models of human diseases are invaluable and inevitable elements in identifying and testing novel treatments for serious diseases, including severe infections. Planning and conducting investigator-initiated human trials are generally accepted as being enormously challenging. In contrast, it is often underestimated how much planning, including background and modifying experiments, is needed to establish a relevant infectious disease animal model. However, representative animal infectious models, well designed to test generated hypotheses, are useful to improve our understanding of pathogenesis, virulence factors and host response and to identify novel treatment candidates and therapeutic strategies. Such results can subsequently proceed to clinical testing if suitable. The present review aims at presenting all the pulmonary Pseudomonas aeruginosa infectious models we have knowledge of and the detailed descriptions of established animal models in our laboratory focusing on macrolide therapy are presented.

Chronic bronchial infection and incident cardiovascular events in chronic obstructive pulmonary disease patients: A long-term observational study

BACKGROUND AND OBJECTIVE

Cardiovascular (CV) diseases are frequent in patients with chronic obstructive pulmonary disease (COPD). Likewise, chronic bronchial infection (CBI) is also frequent in COPD and it is associated with systemic inflammation, a well-known CV risk factor. The objective of this study was to investigate the relationship between CBI, systemic inflammation and incident CV events.

METHODS

A post hoc analysis of prospectively collected cohort of 201 COPD patients [Global Initiative for Chronic Obstructive Lung Disease (GOLD) II-IV] followed up every 3-6 months for 84 months was conducted. CBI was defined as ≥3 positive pathogenic microorganisms sputum cultures over 1 year, separated by ≥3 months. Systemic inflammation was assessed by circulating levels of C-reactive protein and fibrinogen. Fatal and non-fatal CV events, including coronary and cerebrovascular events as well as arrhythmia episodes, were prospectively recorded. For analysis, they were analysed separately and combined in a composite variable.

RESULTS

As hypothesized, CBI was associated with persistent systemic inflammation and a significantly higher incidence of CV events (HR: 3.88; 95% CI: 1.83-8.22), mainly of coronary origin independent of age, number and severity of exacerbations, comorbidities, other CV risk factors, lung function, BMI, smoking status and treatments. These associations were particularly significant in patients with CBI by Pseudomonas aeruginosa (PA).

CONCLUSION

CBI, particularly by PA, is associated with sustained and enhanced systemic inflammation and a higher incidence of CV events (especially coronary events). The possibility that treating CBI may decrease systemic inflammation and CV events in COPD deserves prospective, interventional studies.

A wide-ranging Pseudomonas aeruginosa PeptideAtlas build: A useful proteomic resource for a versatile pathogen

Pseudomonas aeruginosa is an important opportunistic human pathogen with high prevalence in nosocomial infections. This microorganism is a good model for understanding biological processes such as the quorum-sensing response, the metabolic integration of virulence, the mechanisms of global regulation of bacterial physiology, and the evolution of antibiotic resistance. Till now, P. aeruginosa proteomic data, although available in several on-line repositories, were dispersed and difficult to access. In the present work, proteomes of the PAO1 strain grown under different conditions and from diverse cellular compartments have been joined to build the Pseudomonas PeptideAtlas. This resource is a comprehensive mass spectrometry-derived peptide and inferred protein database with 71.3% coverage of the total predicted proteome of P. aeruginosa PAO1, the highest coverage among bacterial PeptideAtlas datasets. The proteins included cover 89% of metabolic proteins, 72% of proteins involved in genetic information processing, 83% of proteins responsible for environmental information processing, more than 88% of the ones related to quorum sensing and biofilm formation, and 89% of proteins responsible for antimicrobial resistance. It exemplifies a necessary tool for targeted proteomics studies, system-wide observations, and cross-species observational studies. The manuscript describes the building of the PeptideAtlas and the contribution of the different proteomic data used. SIGNIFICANCE: Pseudomonas aeruginosa is among the most versatile human bacterial pathogens. Studies of its proteome are very important as they can reveal virulence factors and mechanisms of antibiotic resistance. The construction of a proteomic resource such as the PeptideAtlas enables targeted proteomics studies, system-wide observations, and cross-species observational studies.