Pathogens in COPD exacerbations identified by comprehensive real-time PCR plus older methods

Rationale and protocol for a prospective cohort study of respiratory viral infections in patients admitted from emergency departments of community hospitals: Effect of respiratory Virus infection on EmeRgencY admission (EVERY) study

INTRODUCTION

Respiratory syncytial virus (RSV) is a causative virus for the common cold worldwide and can result in hospitalisations and even death in patients with high-risk conditions and older adults. However, the relationship between RSV or other incidental respiratory infections and acute exacerbations of underlying conditions has not been well investigated. The primary objective of this study is to estimate RSV prevalence, risk factors for adverse outcomes or hospitalisation and their effect on the hospital course of patients with acute respiratory symptoms admitted from emergency departments. Furthermore, we evaluate the prevalence of other respiratory viruses associated with respiratory symptoms.

METHODS AND ANALYSIS

We are conducting a multicentre prospective cohort study in Japan. We plan to enrol 3000 consecutive patients admitted from emergency departments with acute respiratory symptoms or signs from 1 July 2023 to 30 June 2024. A nasopharyngeal swab is obtained within 24 hours of admission and the prevalence of RSV and other respiratory viruses is measured using the FilmArray Respiratory 2.1 panel. Paired serum samples are collected from patients with suspected lower respiratory infections to measure RSV antibodies at admission and 30 days later. Information on patients' hospital course is retrieved from the electronic medical records at discharge, death or 30 days after admission. Furthermore, information on readmission to the hospital and all-cause mortality is collected 180 days after admission. We assess the differences in clinical outcomes between patients with RSV or other respiratory viruses and those without, adjusting for baseline characteristics. Clinical outcomes include in-hospital mortality, length of hospital stay, disease progression, laboratory tests and management of respiratory symptoms or underlying conditions.

ETHICS AND DISSEMINATION

The study protocol was approved by the institutional review boards of participating hospitals. Our study reports will be published in academic journals as well as international meetings.

TRIAL REGISTRATION NUMBER

NCT05913700.

Impact of Antibiotics Used for Acute Aspiration Bronchitis on the Prevention of Pneumonia

BACKGROUNDS

It remains unclear if antibiotics should be used for the treatment of acute aspiration bronchitis to prevent the development of pneumonia. This study aimed to assess the associations between the use of antibiotics and the development of pneumonia among patients with acute aspiration bronchitis.

METHODS

We retrospectively reviewed consecutive patients with acute aspiration bronchitis aged ≥75 years. Acute aspiration bronchitis was defined as a condition with aspiration risk, high fever (body temperature, ≥37.5 °C), respiratory symptoms, and the absence of evidence of pneumonia.

RESULTS

There was no significant difference in the incidence of pneumonia between patients treated with and without antibiotics for acute aspiration bronchitis (6/44, 14% vs. 31/143, 22%; p = 0.242). Lower estimated glomerular filtration rate (adjusted odds ratio, 0.956; 95% confidence interval, 0.920-0.993) was significantly associated with the development of pneumonia.

CONCLUSIONS

Antibiotic administration should not be routinely recommended to prevent pneumonia following acute aspiration bronchitis, and patients with decreased renal function should be closely monitored. A randomized controlled trial is necessary to validate these results.

COPD Phenotyping

COPD is a heterogeneous condition, the onset and trajectory of which is influenced not only by tobacco exposure but also an individual's genetics and the exposures they accumulate over their life course. In such a complex chronic disease, phenotyping individuals based on similar clinical or molecular characteristics can aid in guiding appropriate therapeutic management. Treatable traits, characteristics for which evidence exists for a specific favorable treatment response, are increasingly incorporated into COPD clinical guidelines. But the COPD phenotyping literature is evolving. Innovations in lung imaging and physiologic metrics, as well as omics technologies and biomarker science, are contributing to a better understanding of COPD heterogeneity. This review summarizes the evolution of COPD phenotyping, the current use of phenotyping to direct clinical care, and how innovations in clinical and molecular approaches to unraveling disease heterogeneity are refining our understanding of COPD phenotypes.

Seasonal Dynamics of the Upper Respiratory Tract Microbiome in Chronic Obstructive Pulmonary Disease

Introduction

Increasing evidence suggests that seasonal changes can trigger the alternation of airway microbiome. However, the dynamics of the upper airway bacterial ecology of chronic obstructive pulmonary disease (COPD) patients across different seasons remains unclear.

Methods

In this study, we present a 16S ribosomal RNA survey of the airway microbiome on 72 swab samples collected in different months (March, May, July, September, and November) in 2019 from 18 COPD patients and from six resampled patients in November in 2020.

Results

Our study uncovered a dynamic airway microbiota where changes appeared to be associated with seasonal alternation in COPD patients. Twelve clusters of temporal patterns were displayed by differential and clustering analysis along the time course, systematically revealing distinct microbial taxa that prefer to grow in cool and warm seasons, respectively. Moreover, the upper airway microbiome composition was relatively stable in the same season in different years.

Discussion

Given the tight association between airway microbiome and COPD disease progression, this study can provide useful information for clinically understanding the seasonal trend of disease phenotypes in COPD patients.

The Role of Early Warning Scoring Systems NEWS and MEWS in the Acute Exacerbation of COPD

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are the most devastating events in the course of the disease. Our aim was to investigate the value of early warning scoring systems: National Early Warning Score (NEWS) and Modified Early Warning Score (MEWS) in AECOPD. This is a prospective observational study of patients with AECOPD who were admitted at hospital. The NEWS and MEWS scores were registered at admission (NEWS-d1, MEWS-d1) and on the second day (NEWS-d2, MEWS-d2). A nasopharyngeal and sputum sample was taken for culture. Follow-up was done at 3 and 6 months after hospitalization. Any possible correlations between NEWS and MEWS and other parameters of COPD were explored. A cohort of 64 patients were included. In-hospital mortality was 4.7% while total mortality at 6 months was 26%. We did not find any significant correlation between in-hospital mortality and any of the scores but we could show a higher mortality and more frequent AECOPD at 6 months of follow-up for those with higher NEWS-d2. NEWS-d2 was associated with higher pCO₂ at presentation and a more frequent use of NIV. Higher NEWS-d1 and NEWS-d2 were predictive of a longer hospital stay. The presence of pathogens in the nasopharyngeal sample was related with a higher reduction of both scores on the second day. We therefore support the superiority of NEWS in the evaluation of hospitalized patients with AECOPD. A remaining high NEWS at the second day of hospital stay signals a high risk of hypercapnia and need of NIV but also higher mortality and more frequent exacerbations at 6 months after AECOPD.

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.

Plant-Derived Natural Products as Lead Agents against Common Respiratory Diseases

Never has the world been more challenged by respiratory diseases (RDs) than it has witnessed in the last few decades. This is evident in the plethora of acute and chronic respiratory conditions, ranging from asthma and chronic obstructive pulmonary disease (COPD) to multidrug-resistant tuberculosis, pneumonia, influenza, and more recently, the novel coronavirus (COVID-19) disease. Unfortunately, the emergence of drug-resistant strains of pathogens, drug toxicity and side effects are drawbacks to effective chemotherapeutic management of RDs; hence, our focus on natural sources because of their unique chemical diversities and novel therapeutic applications. This review provides a summary on some common RDs, their management strategies, and the prospect of plant-derived natural products in the search for new drugs against common respiratory diseases.

Extracellular Vesicles as Central Mediators of COPD Pathophysiology

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous, smoking-related disease of significant global impact. The complex biology of COPD is ultimately driven by a few interrelated processes, including proteolytic tissue remodeling, innate immune inflammation, derangements of the host-pathogen response, aberrant cellular phenotype switching, and cellular senescence, among others. Each of these processes are engendered and perpetuated by cells modulating their environment or each other. Extracellular vesicles (EVs) are powerful effectors that allow cells to perform a diverse array of functions on both adjacent and distant tissues, and their pleiotropic nature is only beginning to be appreciated. As such, EVs are candidates to play major roles in these fundamental mechanisms of disease behind COPD. Furthermore, some such roles for EVs are already established, and EVs are implicated in significant aspects of COPD pathogenesis. Here, we discuss known and potential ways that EVs modulate the environment of their originating cells to contribute to the processes that underlie COPD.

Prevalence, Pattern, Risks Factors and Consequences of Antibiotic Resistance in COPD: A Systematic Review

A concern of antibiotic use in chronic obstructive pulmonary disease (COPD) is the emergence and propagation of antimicrobial resistance (AMR). A systematic review was conducted to determine prevalence, pattern, risk factors and consequences of AMR in COPD. Bibliographic databases were searched from inception to November 2020, with no language restrictions, including studies of any design that included patients with COPD and reported prevalence and pattern of AMR. 2748 unique titles and abstracts were identified, of which 63 articles, comprising 26,387 patients, met inclusion criteria. Forty-four (69.8%) studies were performed during acute exacerbation. The median prevalence of AMR ranged from 0-100% for Pseudomonas aeruginosa, Moraxella catarrhalis, Klebsiella pneumoniae and Acinetobacter baumannii. Median resistance rates of H influenzae and S pneumoniae were lower by comparison, with maximum rates ≤40% and ≤46%, respectively, and higher for Staphylococcus aureus. There was a trend towards higher rates of AMR in patients with poorer lung function and greater incidence of previous antibiotic exposure and hospitalisation. The impact of AMR on mortality was unclear. Data regarding antimicrobial susceptibility testing techniques and the impact of other risk factors or consequences of AMR were variable or not reported. This is the first review to systematically unify data regarding AMR in COPD. AMR is relatively common and strategies to optimise antibiotic use could be valuable to prevent the currently under-investigated potential adverse consequences of AMR.Supplemental data for this article is available online at https://doi.org/10.1080/15412555.2021.2000957 .

A Multicenter Study to Identify the Respiratory Pathogens Associated with Exacerbation of Chronic Obstructive Pulmonary Disease in Korea

BACKGROUND

Although respiratory tract infection is one of the most important factors triggering acute exacerbation of chronic obstructive pulmonary disease (AE-COPD), limited data are available to suggest an epidemiologic pattern of microbiology in South Korea.

METHODS

A multicenter observational study was conducted between January 2015 and December 2018 across 28 hospitals in South Korea. Adult patients with moderate-to-severe acute exacerbations of COPD were eligible to participate in the present study. The participants underwent all conventional tests to identify etiology of microbial pathogenesis. The primary outcome was the percentage of different microbiological pathogens causing AE-COPD. A comparative microbiological analysis of the patients with overlapping asthma-COPD (ACO) and pure COPD was performed.

RESULTS

We included 1,186 patients with AE-COPD. Patients with pure COPD constituted 87.9% and those with ACO accounted for 12.1%. Nearly half of the patients used an inhaled corticosteroid-containing regimen and one-fifth used systemic corticosteroids. Respiratory pathogens were found in 55.3% of all such patients. Bacteria and viruses were detected in 33% and 33.2%, respectively. Bacterial and viral coinfections were found in 10.9%. The most frequently detected bacteria were Pseudomonas aeruginosa (9.8%), and the most frequently detected virus was influenza A (10.4%). Multiple bacterial infections were more likely to appear in ACO than in pure COPD (8.3% vs. 3.6%, p=0.016).

CONCLUSION

Distinct microbiological patterns were identified in patients with moderate-to-severe AE-COPD in South Korea. These findings may improve evidence-based management of patients with AE-COPD and represent the basis for further studies investigating infectious pathogens in patients with COPD.

Peripheral blood microbial signatures in current and former smokers

The human microbiome has a role in the development of multiple diseases. Individual microbiome profiles are highly personalized, though many species are shared. Understanding the relationship between the human microbiome and disease may inform future individualized treatments. We hypothesize the blood microbiome signature may be a surrogate for some lung microbial characteristics. We sought associations between the blood microbiome signature and lung-relevant host factors. Based on reads not mapped to the human genome, we detected microbial nucleic acids through secondary use of peripheral blood RNA-sequencing from 2,590 current and former smokers with and without chronic obstructive pulmonary disease (COPD) from the COPDGene study. We used the Genome Analysis Toolkit (GATK) microbial pipeline PathSeq to infer microbial profiles. We tested associations between the inferred profiles and lung disease relevant phenotypes and examined links to host gene expression pathways. We replicated our analyses using a second independent set of blood RNA-seq data from 1,065 COPDGene study subjects and performed a meta-analysis across the two studies. The four phyla with highest abundance across all subjects were Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes. In our meta-analysis, we observed associations (q-value < 0.05) between Acinetobacter, Serratia, Streptococcus and Bacillus inferred abundances and Modified Medical Research Council (mMRC) dyspnea score. Current smoking status was associated (q < 0.05) with Acinetobacter, Serratia and Cutibacterium abundance. All 12 taxa investigated were associated with at least one white blood cell distribution variable. Abundance for nine of the 12 taxa was associated with sex, and seven of the 12 taxa were associated with race. Host-microbiome interaction analysis revealed clustering of genera associated with mMRC dyspnea score and smoking status, through shared links to several host pathways. This study is the first to identify a bacterial microbiome signature in the peripheral blood of current and former smokers. Understanding the relationships between systemic microbial signatures and lung-related phenotypes may inform novel interventions and aid understanding of the systemic effects of smoking.

Airway Bacteria Quantification Using Polymerase Chain Reaction Combined with Neutrophil and Eosinophil Counts Identifies Distinct COPD Endotypes

BACKGROUND

Chronic obstructive pulmonary disease (COPD) inflammatory endotypes are associated with different airway microbiomes. We used quantitative polymerase chain reaction (qPCR) analysis of sputum samples to establish the bacterial load upper limit in healthy controls; these values determined the bacterial colonisation prevalence in a longitudinal COPD cohort. Bacteriology combined with sputum inflammatory cells counts were used to investigate COPD endotypes.

METHODS

Sixty COPD patients and 15 healthy non-smoking controls were recruited. Sputum was analysed by qPCR (for Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae and Psuedomonas aeruginosa) and sputum differential cell counts at baseline and 6 months.

RESULTS

At baseline and 6 months, 23.1% and 25.6% of COPD patients were colonised with H. influenzae, while colonisation with other bacterial species was less common, e.g., S. pneumoniae-1.9% and 5.1%, respectively. H. influenzae + ve patients had higher neutrophil counts at baseline (90.1% vs. 67.3%, p < 0.01), with similar results at 6 months. COPD patients with sputum eosinophil counts ≥3% at ≥1 visit rarely showed bacterial colonisation.

CONCLUSIONS

The prevalence of H. influenzae colonisation was approximately 25%, with low colonisation for other bacterial species. H. influenzae colonisation was associated with sputum neutrophilia, while eosinophilic inflammation and H. influenzae colonisation rarely coexisted.

Atypical Pathogen Distribution in Chinese Hospitalized AECOPD Patients: A Multicenter Cross-Sectional Study

Purpose

The proportion of atypical pathogens in patient with AECOPD within mainland China is unknown. The objectives of this study were to determine the distribution of atypical pathogens among Chinese patients with AECOPD, to evaluate the clinical characteristics of different atypical pathogen infections, and to compare different detection methods for atypical pathogens.

Patients and Methods

Specimens were collected from patients with AECOPD from March 2016 to November 2018 at eleven medical institutions in eight cities in China. Double serum, sputum, and urine samples were obtained from 145 patients. Serological and nucleic acid tests were used to assess for Mycoplasma pneumonia and Chlamydia pneumoniae; serological, urinary antigen, and nucleic acid tests were applied to detect Legionella pneumophila. The clinical characteristics of atypical pathogen-positive and -negative groups were also compared.

Results

The overall positivity rate for Mycoplasma pneumoniae was 20.69% (30/145), with the highest rate being 20.00% (29/145) when determined by passive agglutination.The overall positive rates for Chlamydia pneumoniae and Legionella pneumophila were 29.66% (43/145) and 10.34% (15/145), respectively. The most common serotype of Legionella pneumophila was type 6. The maximum hospitalized body temperature, ratio of eosinophils, C-reactive protein (CRP) level, and procalcitonin (PCT) level of the Mycoplasma pneumoniae-positive group were significantly higher than those of the Mycoplasma pneumoniae-negative group. Patients in the Chlamydia pneumoniae-positive group smoked more, had higher proportions of comorbidities and frequent aggravations in the previous two years than those in the Chlamydia pneumoniae-negative group. Furthermore, the forced expiratory volume in one second to forced vital capacity (FEV₁/FVC) ratio assessment of lung function was higher, and the concentration of arterial blood bicarbonate (HCO₃ ^-) was lower in the Legionella pneumophila-positive group than in the Legionella pneumophila-negative group.

Conclusion

Overall, atypical pathogens play an important role in AECOPD. Regarding the testing method, serological testing is a superior method to nucleic acid testing.

Pulmonary biofilm-based chronic infections and inhaled treatment strategies

Certain pulmonary diseases, such as cystic fibrosis (CF), non-CF bronchiectasis, chronic obstructive pulmonary disease, and ventilator-associated pneumonia, are usually accompanied by respiratory tract infections due to the physiological alteration of the lung immunological defenses. Recurrent infections may lead to chronic infection through the formation of biofilms. Chronic biofilm-based infections are challenging to treat using antimicrobial agents. Therefore, effective ways to eradicate biofilms and thus relieve respiratory tract infection require the development of efficacious agents for biofilm destruction, the design of delivery carriers with biofilm-targeting and/or penetrating abilities for these agents, and the direct delivery of them into the lung. This review provides an in-depth description of biofilm-based infections caused by pulmonary diseases and focuses on current existing agents that are administered by inhalation into the lung to treat biofilm, which include i) inhalable antimicrobial agents and their combinations, ii) non-antimicrobial adjuvants such as matrix-targeting enzymes, mannitol, glutathione, cyclosporin A, and iii) liposomal formulations of anti-biofilm agents. Finally, novel agents that have shown promise against pulmonary biofilms as well as traditional and new devices for pulmonary delivery of anti-biofilm agents into the lung are also discussed.

Bacterial and Viral Infection in Patients Hospitalized for Acute Exacerbation of Chronic Obstructive Pulmonary Disease: Implication for Antimicrobial Management and Clinical Outcome

Patients with chronic obstructive pulmonary disease (COPD) exhibit frequent acute exacerbations (AE). The objectives of this study were first to evaluate the prevalence of pathogens associated to these episodes by combining conventional bacteriology and multiplex viral and bacterial PCR assays in sputum specimens, and second to determine whether C-reactive protein (CRP) value and clinical outcome could be influenced by the type of microbial agent(s) recovered from these samples. A cohort of 84 Tunisian patients hospitalized at the emergency room for AECOPD was investigated prospectively for the semi-quantitative detection of bacteria by conventional culture (the threshold of positivity was of 10⁷ CFU/ml) and for the detection of viral genome and DNA of atypical bacteria by quantitative PCR using two commercial multiplex respiratory kits (Seegene and Fast-track). The two kits exhibited very similar performances although the Seegene assay was a bit more sensitive. A large number and variety of pathogens were recovered from the sputum samples of these 84 patients, including 15 conventional bacteria, one Chlamydia pneumoniae and 63 respiratory viruses, the most prevalent being rhinoviruses (n = 33) and influenza viruses (n = 13). From complete results available for 74 patients, the presence of bacteria was significantly associated with risk of recurrence at 6 and 12 months post-infection. The combination of these different markers appears useful for delineating correctly the antimicrobial treatment and for initiating a long-term surveillance in those patients with high risk of recurrent exacerbation episodes. A prospective study is required for confirming the benefits of this strategy aimed at improving the stewardship of antibiotics.

The role of typical and atypical pathogens in acute exacerbations of chronic obstructive pulmonary disease

OBJECTIVES

The exact role of Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila in the development of chronic obstructive pulmonary disease exacerbations remains to be elucidated. This study was conducted to identify nonspecific and atypical pathogens associated with acute exacerbations of COPD.

MATERIALS AND METHODS

Between February 2013 and February 2015, 107 patients were analyzed. Sixty-nine comprised the inpatient and 38 comprised the outpatient treatment group.

RESULTS

When nonspecific culture results were taken into consideration only a causative organism could be detected in 46.7% of the patients. The detection rate increased to 85.1% with the additional use of polymerase chain reaction (PCR), direct fluorescent antibody (DFA) test, and culture methods. More than one causative agent was responsible for COPD exacerbation in 53.3% of patients: two agents in 37.3%, three agents in 15%, and four agents in 0.9%. H. influenzae was detected in 63 (58.9%) patients, S. pneumoniae in 57 (53.2%), P. aeruginosa in 15 (14.0%), and L. pneumophila in 11 (10%). L. pneumophila was the more commonly isolated agent in the inpatient group (P = 0.002). Patients receiving continuous oxygen therapy and noninvasive mechanical ventilation were more likely to have an exacerbation associated with P. aeruginosa (P = 0.008 and P = 0.009, respectively).

CONCLUSION

The additional use of DFA for Legionella and multiplex PCR in combination with nonspecific microbiological culturing methods greatly improves the ability to identify infectious agents in acute exacerbations of COPD. There should be a high index of suspicion for P.aeruginosa as a causative organism, particularly in subjects receiving continuous oxygen therapy and/or using NIV and L. pneumophila should certainly be taken into consideration in severe COPD exacerbations.

The airway microbiota and exacerbations of COPD

Aim

The aim of this study was to investigate whether the compositionality of the lower airway microbiota predicts later exacerbation risk in persons with COPD in a cohort study.

Materials and methods

We collected lower airways microbiota samples by bronchoalveolar lavage and protected specimen brushes, and oral wash samples from 122 participants with COPD. Bacterial DNA was extracted from all samples, before we sequenced the V3-V4 region of the 16S RNA gene. The frequency of moderate and severe COPD exacerbations was surveyed in telephone interviews and in a follow-up visit. Compositional taxonomy and α and β diversity were compared between participants with and without later exacerbations.

Results

The four most abundant phyla were Firmicutes, Bacteroidetes, Proteobacteria and Fusobacteria in both groups, and the four most abundant genera were Streptococcus, Veillonella, Prevotella and Gemella. The relative abundances of different taxa showed a large variation between samples and individuals, and no statistically significant difference of either compositional taxonomy, or α or β diversity could be found between participants with and without COPD exacerbations within follow-up.

Conclusion

The findings from the current study indicate that individual differences in the lower airway microbiota in persons with COPD far outweigh group differences between frequent and nonfrequent COPD exacerbators, and that the compositionality of the microbiota is so complex as to present large challenges for use as a biomarker of later exacerbations.

Contrary to previous reports, in this study there were no significant associations between the lung microbiota in stable COPD and COPD exacerbation frequencyhttps://bit.ly/2ZVcNdG

Potential clinical utility of multiple target quantitative polymerase chain reaction (qPCR) array to detect microbial pathogens in patients with chronic obstructive pulmonary disease (COPD)

Background

Culture-independent methods such as quantitative polymerase chain reaction (qPCR) are more sensitive for detecting pathogens than conventional culture. This study aimed to test the clinical potential of a multiple target qPCR array in identifying sputum pathogens, compared to traditional culture.

Methods

Forty chronic obstructive pulmonary disease (COPD) patients provided spontaneous sputum and blood samples during an exacerbation event (n=25 patients) and in stable state (n=15 patients). Sputum was processed and analysed by microscopy, culture and sensitivity testing (MCS) to identify living microbial isolates, and multiple target qPCR (44 targets for bacterial and fungal pathogens and antibiotic resistance genes), and 16S rRNA gene sequencing.

Results

Six microbial isolates (5 bacterial, 1 fungal) were cultured from 20 exacerbation and 10 stable patient sputum samples. Four of these microbial isolates had their presence in patient sputum confirmed by qPCR. All bacterial targets detected by qPCR were further confirmed by 16S rRNA gene sequencing at a genus level. qPCR identified significantly more bacterial pathogens than culture (P<0.001). The most prevalent bacterial species identified by qPCR were Streptococcus pneumoniae (72% of patients), Pseudomonas aeruginosa (40%), Prevotella oris (32%) and Haemophilus influenzae (17%). Microbial species diversity and richness were not significantly different between samples obtained from exacerbating and clinically stable cases. 16S rRNA gene sequencing identified Pseudomonas 4408227 (P=0.022, FDR =0.043 AUC =0.72) as a significantly different bacterial OTU (operational taxonomic units) in exacerbation sputum samples compared to stable state samples.

Conclusions

Multiple target qPCR was more sensitive for detection of sputum pathogens in COPD patients than conventional culture. 16S rRNA gene sequencing confirmed the identity at a genus level of all bacterial targets detected by qPCR, as well as identifying bacterial OTUs that could potentially be used to distinguish between exacerbation and stable COPD disease states. Multiple target qPCR pathogen detection in the sputum of COPD patients warrants further investigation to determine how it may influence COPD clinical management.

Bacterial infections in acute exacerbation of chronic obstructive pulmonary disease: a systematic review and meta-analysis

OBJECTIVE

Due to the importance of Chronic obstructive pulmonary disease (COPD) as the fourth cause of mortality worldwide and the lack of studies evaluating the prevalence of bacterial infections in disease exacerbation, this systematic review and meta-analysis was performed to determine the prevalence rate of bacterial infections in COPD patients.

METHODS

PubMed, ISI Web of Science, and Scopus databases were systematically searched for population-based prevalence studies (1980-2018). MeSH terms for "Bacterial infections" and "AECOPD" were used as search keywords. The selected studies were filtered according to the inclusion and exclusion criteria. Fixed and random-effects models were used for estimation of summary effect sizes. Between-study heterogeneity, as well as publication bias, were calculated.

RESULTS

Finally, 118 out of 31,440 studies were selected. The overall estimation of the prevalence of bacterial infection was 49.59% [95% confidence interval (CI) 0.4418-0.55]. The heterogeneity in estimating the pooled prevalence of bacterial infections was shown in the studies (Cochran Q test: 6615, P < 0.0001, I² = 98.23%). In addition, S. pneumoniae, H. influenzae, M. catarrhalis, A. baumannii, P. aeruginosa, and S. aureus were the most prevalent reported bacteria.

CONCLUSIONS

Our results as the first meta-analysis for the issue demonstrated that bacterial infections are an important risk factor for AECOPD. Further studies must be performed for understanding the exact role of bacterial agents in AECOPD and help physicians for more applicable preventive and therapeutic measurements.

Efficacy and safety of cefditoren pivoxil for exacerbations of chronic obstructive pulmonary disease: A prospective multicenter interventional study

Oral antibiotic therapy for patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) usually involves an aminopenicillin with clavulanic acid, a macrolide, or a quinolone. To date, however, the clinical efficacy and safety of the oral cephalosporin cefditoren pivoxil has not been evaluated in Japanese patients with acute exacerbations of COPD. We conducted a prospective, multicenter, single arm, interventional study from January 2013 to March 2017 to determine the efficacy and safety of oral administration of 200 mg cefditoren pivoxil three times daily for 7 days in a cohort of 29 eligible patients from 15 hospitals. The mean age (SD) of participants was 73.1 (8.1) years and 28 had a smoking history (the mean [SD] of smoking index, 1426.7 [931.7]). The primary efficacy endpoint was clinical response (cure rate) at test of cure, which was set at 5-10 days after treatment ceased. Of the 23 patients finally analyzed, cure was achieved in 15 (65.2%), while 8 (34.8%) remained uncured. Previous experience of acute exacerbations significantly affected the cure rate: none of the three patients who had at least two prior exacerbations were cured, while 15 of the 20 patients with one or fewer prior exacerbations were cured (p = 0.032). The microbiological eradication rate was 88.9% at test of cure. During treatment, mild pneumonia was reported as an adverse event in one patient (3.4%) but resolved within 10 days of onset. We conclude that cefditoren pivoxil represents a viable alternative for antibiotic therapy in patients with few prior exacerbations.

Phenotyping and outcomes of hospitalized COPD patients using rapid molecular diagnostics on sputum samples

Background

Etiologies of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are heterogeneous. We phenotyped severe AECOPD based on molecular pathogen detection of sputum samples collected at hospitalization of COPD patients and determined their outcomes.

Methods

We phenotyped 72 sputum samples of COPD patients who were hospitalized with a primary diagnosis of AECOPD using a molecular array that detected common bacterial and viral respiratory pathogens. Based on these results, the patients were classified into positive or negative pathogen groups. The pathogen-positive group was further divided into virus or bacteria subgroups. Admission day 1 blood samples were assayed for N-terminal prohormone brain natriuretic peptide, CRP, and complete blood counts.

Results

A total of 52 patients had a positive result on the array, while 20 patients had no pathogens detected. The most common bacterial pathogen detected was Haemophilus influenzae and the most common virus was rhinovirus. The pathogen-negative group had the worse outcomes with longer hospital stays (median 6.5 vs 5 days for bacteria-positive group, P=0.02) and a trend toward increased 1-year mortality (P=0.052). The bacteria-positive group had the best prognosis, whereas the virus-positive group had outcomes somewhere in between the bacteria-positive and pathogen-negative groups.

Conclusion

Molecular diagnostics on sputum can rapidly phenotype serious AECOPD into bacteria-, virus-, or pathogen-negative groups. The bacteria-positive group appears to have the best prognosis, while pathogen-negative group has the worst. These data suggest that AECOPD is a heterogeneous event and that accurate phenotyping of AECOPD may lead to novel management strategies that are personalized and more precise.

A Comparison between Two Pathophysiologically Different yet Microbiologically Similar Lung Diseases: Cystic Fibrosis and Chronic Obstructive Pulmonary Disease

Cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) are chronic pulmonary diseases that affect ~70,000 and 251 million individuals worldwide, respectively. Although these two diseases have distinctly different pathophysiologies, both cause chronic respiratory insufficiency that erodes quality of life and causes significant morbidity and eventually death. In both CF and COPD, the respiratory microbiome plays a major contributing role in disease progression and morbidity. Pulmonary pathogens can differ dramatically during various stages of each disease and frequently cause acute worsening of lung function due to disease exacerbation. Despite some similarities, outcome and timing/type of exacerbation can also be quite different between CF and COPD. Given these clinical distinctions, both patients and physicians should be aware of emerging therapeutic options currently being offered or in development for the treatment of lung infections in individuals with CF and COPD. Although interventions are available that prolong life and mitigate morbidity, neither disorder is curable. Both acute and chronic pulmonary infections contribute to an inexorable downward course and may trigger exacerbations, culminating in loss of lung function or respiratory failure. Knowledge of the pulmonary pathogens causing these infections, their clinical presentation, consequences, and management are, therefore, critical. In this review, we compare and contrast CF and COPD, including underlying causes, general outcomes, features of the lung microbiome, and potential treatment strategies.

[Integral approach to the acute exacerbation of chronic obstructive pulmonary disease]

Chronic obstructive pulmonary disease is a set of clinical processes that have in common a chronic and progressive obstruction to airflow, with episodes of exacerbation. These exacerbations are more frequent and severe over time, deteriorating the lung function. The main cause of exacerbations is bacterial infection. There are multiple guidelines and documents that statement the management of this pathology. However, they focus primarily on the treatment during the stable phase. This document addresses the problem of acute exacerbation due to an infection from a multidisciplinary perspective, focusing on the integral approach to the process, and including etiology, microbiological studies, resistance to antimicrobials, risk stratification and initial empirical therapeutic management (antibiotic and concomitant). In addition, it includes an approach to more complex aspects such as the management of special populations (elderly and immunosuppressed) or therapeutic failure. Finally, more controversial topics such as prophylaxis of infection or palliative treatment are specifically discussed.

Use of serology and polymerase chain reaction to detect atypical respiratory pathogens during acute exacerbation of chronic obstructive pulmonary disease

BACKGROUND/AIMS

To use serological and multiplex polymerase chain reaction (PCR) assays to examine sputum samples from patients experiencing acute exacerbation of chronic obstructive pulmonary disease (AECOPD) for the presence of atypical pathogens, including Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila.

METHODS

From September 2012 to February 2014, 341 patients with AECOPD attending outpatient clinics were enrolled as part of a randomized, double-blind, multicenter study. A commercial enzyme-linked immunosorbent assay was used to measure serum immunoglobulin M (IgM) and IgG antibody titers on the first day of the study and at 36 days post-enrollment. Multiplex PCR was used to test sputum samples for the presence of atypical pathogens. A urinary antigen test for L. pneumophila was performed on the first day.

RESULTS

Nineteen patients (5.6%) showed serological evidence of acute infection with M. pneumoniae. Also, one and seven patients (2%) showed serological evidence of acute infection with C. pneumoniae and L. pneumophila, respectively. All DNA samples were negative for M. pneumoniae, C. pneumoniae, and L. pneumophila according to PCR. Only one urine sample was positive for L. pneumophila antigen, but serologic evidence was lacking.

CONCLUSION

Serological testing suggested that infection by atypical pathogens during AECOPD was relatively uncommon. In addition, PCR provided no direct evidence of infection by atypical pathogens. Thus, atypical pathogens may not be a major cause of AECOPD in South Korea.

Identification and assessment of COPD exacerbations

Chronic Obstructive Pulmonary Disease (COPD) exacerbations play a central role in the disease natural history of the disease, affecting its overall severity, decreasing pulmonary function, worsening underlying co-morbidities, impairing quality of life (QoL) and leading to severe morbidity and mortality. Therefore, identification and correct assessment of COPD exacerbations is paramount, given it will strongly influence therapy success. For the identification of exacerbations, several questionnaires exist, with varying degrees of complexity. However, most questionnaires remain of limited clinical utility, and symptom scales seem to be more useful in clinical practice. In the assessment of exacerbations, the type and degree of severity should be ascertained in order to define the management setting and optimize treatment options. Still, a consensual and universal classification system to assess the severity and type of an exacerbation is lacking, and there are no established criteria for less severely ill patients not requiring hospital assessment. This might lead to under-reporting of minor to moderate exacerbations, which has an impact on patients' health status. There is a clear unmet need to develop clinically useful questionnaires and a comprehensive system to evaluate the severity of exacerbations that can be used in all settings, from primary health care to general hospitals.

Detection of pathogens by real-time PCR in adult patients with acute exacerbation of bronchial asthma

BACKGROUND

Respiratory tract infection is a major cause of acute exacerbation of bronchial asthma (AEBA). Although recent findings suggest that common bacteria are causally associated with AEBA, a comprehensive epidemiologic analysis of infectious pathogens including common/atypical bacteria and viruses in AEBA has not been performed. Accordingly, we attempted to detect pathogens during AEBA by using real-time polymerase chain reaction (PCR) in comparison to conventional methods.

METHODS

We prospectively enroled adult patients with AEBA from August 2012 to March 2014. Infectious pathogens collected in nasopharyngeal swab and sputum samples were examined in each patient by conventional methods and real-time PCR, which can detect 6 bacterial and 11 viral pathogens. The causal association of these pathogens with AEBA severity and their frequency of monthly distribution were also examined.

RESULTS

Among the 64 enroled patients, infectious pathogens were detected in 49 patients (76.6%) using real-time PCR and in 14 patients (21.9%) using conventional methods (p < 0.001). Real-time PCR detected bacteria in 29 patients (45.3%) and respiratory viruses in 28 patients (43.8%). Haemophilus influenzae was the most frequently detected microorganism (26.6%), followed by rhinovirus (15.6%). Influenza virus was the significant pathogen associated with severe AEBA. Moreover, AEBA occurred most frequently during November to January.

CONCLUSIONS

Real-time PCR was more useful than conventional methods to detect infectious pathogens in patients with AEBA. Accurate detection of pathogens with real-time PCR may enable the selection of appropriate anti-bacterial/viral agents as a part of the treatment for AEBA.

Worldwide prevalence of viral infection in AECOPD patients: A meta-analysis

Background and objective

Chronic obstructive pulmonary disease (COPD) is a chronic progressive lung disease. On the other hand, viral infections of the airway are associated with the acute exacerbations of COPD. A systematic review and meta-analysis were performed to determine the prevalence rate of viral infections in acute exacerbations of COPD patients.

Methods

PubMed database was systematically searched for population-based prevalence studies (1930–2017). Fixed and random effects models were used for estimation of summary effect-sizes. Between-study heterogeneity and publication bias were also calculated. “Viral infections” and “COPD patients with exacerbations” were the two critical inclusion criteria.

Results

Twenty-eight studies were selected out of 26078 articles for the present review. The overall estimation of the prevalence of viral infection was 0.374 (95% C.I: 0.359–0.388). Also, the evident heterogeneity of viral infection was observed among the studies (Cochran Q test, p value < 0.001 and I-squared = 97.5%). The highest and lowest prevalence rate was related to rhinovirus and echovirus, respectively. Also, the results of this study showed that the prevalence of viral infection in exacerbated COPD patients has fluctuation during the years with a slight increase and decrease.

Conclusions

The results of this systematic review demonstrated that respiratory viral infections have an important role in the acute exacerbation of COPD (AECOPD). In addition, determining the exact geographic epidemiology of these viruses is very important to manage the treatment of these infections.

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Rhinovirus and Echovirus were the most and least common viruses.

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The prevalence of viral infection had a fluctuation by the year of publication.

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PCR resulted in the highest rate of viral detection.

Colonisation of Irish patients with chronic obstructive pulmonary disease by Streptococcus pneumoniae and analysis of the pneumococcal vaccine coverage: a non-interventional, observational, prospective cohort study

OBJECTIVES

To characterise the pattern of colonisation and serotypes of Streptococcus pneumoniae among patients with chronic obstructive pulmonary disease (COPD) who currently receive the 23-valent pneumococcal polysaccharide vaccine (PPV-23) according to vaccination status, use of antibiotics and steroids. To investigate the prevalence of PPV-23 and 13-valent pneumococcal conjugate vaccine (PCV-13) serotypes within the study cohort.

DESIGN

A non-interventional, observational, prospective cohort study with a 12 -month follow-up period inclusive of quarterly study visits.

SETTING

Beaumont Hospital and The Royal College of Surgeons in Ireland Clinical Research Centre, Dublin, Ireland.

PARTICIPANTS

Patients with an established diagnosis of COPD attending a tertiary medical centre.

PRIMARY OUTCOME MEASURE

Colonisation rate of S. pneumoniae in patients with COPD and characterisation of serotypes of S. pneumoniae with correlation to currently available pneumococcal vaccines. Sputum and oropharyngeal swab samples were collected for the isolation of S. pneumoniae.

SECONDARY OUTCOME MEASURE

Seasonality of colonisation of S. pneumoniae and its relationship with the incidence of exacerbations of COPD.

RESULTS

S. pneumoniae was detected in 16 of 417 samples, a colonisation incident rate of 3.8% and in 11 of 133 (8%) patients at least once during the study. The majority of S. pneumoniae isolates were identified in spring and were non-vaccine serotypes for either the PPV-23 or PCV-13 (63%). The colonisation incident rate of S. pneumoniae fluctuated over the four seasons with a peak of 6.6% in spring and the lowest rate of 2.2% occurring during winter. Antibiotic use was highest during periods of low colonisation.

CONCLUSIONS

There is seasonal variation in S. pneumoniae colonisation among patients with COPD which may reflect antibiotic use in autumn and winter. The predominance of non-vaccine types suggests that PCV-13 may have limited impact among patients with COPD in Ireland who currently receive PPV-23.

TRIAL REGISTRATION NUMBER

NCT02535546; post-results.

Outpatient Management for Acute Exacerbations of Obstructive Lung Diseases

Primary care providers tasked with treating acute exacerbations of asthma and chronic obstructive pulmonary disease must be able to recognize exacerbation of symptoms and triage patients based on exacerbation severity to the appropriate level of care. Early treatment with bronchodilators and corticosteroids should be followed by repeated assessments of treatment efficacy. Primary care providers should also provide symptom-guided action plans to empower patients to manage their disease.

Respiratory viruses in acute exacerbations of chronic obstructive pulmonary disease

Objective:

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) cause significant morbidity, mortality, and an inexorable decline of lung function. Data from developed countries have shown viruses to be important causes of AECOPD, but data from developing countries like India are scant. We set out to determine the contribution of viruses in the causation of hospitalized patients with AECOPD.

Methods:

Twin nasopharyngeal/oropharyngeal swabs collected from 233 patients admitted with an acute AECOPD and tested for respiratory viruses including respiratory syncytial virus A and B, parainfluenza were (PIV) 1, 2, 3, and 4, human metapneumovirus (hMPV) A and B, influenza A and B, enterovirus, corona NL65, OC43, and 229E viruses, adenovirus 2 and 4, rhinovirus, and bocavirus, by duplex real time reverse-transcription polymerase chain reaction (qRT-PCR) using CDC approved primers and probes. Samples positive for influenza A were subtyped for A/H1N1pdm09 and A/H3N2 whereas influenza B samples were subtyped into B/Yamagata and B/Victoria subtypes, using primers and probes recommended by CDC, USA.

Results:

Respiratory viruses were detected in 46 (19.7%) cases, influenza A/H3N2 and rhinoviruses being the most common viruses detected. More than one virus was isolated in four cases consisting of hMPV-B + adeno-2 + Inf-B; rhino + H3N2, PIV-1 + rhino; and PIV-1+ hMPV-B in one case each. Ancillary supportive therapeutic measures included bronchodilators, antibiotics, steroids, and ventilation (noninvasive in 42 and invasive in 4). Antiviral therapy was instituted in influenza-positive patients. Three patients with A/H3N2 infection died during hospitalization.

Conclusions:

We conclude that respiratory viruses are important contributors to AECOPD in India. Our data calls for prompt investigation during an exacerbation for viruses to obviate inappropriate antibiotic use and institute antiviral therapy in viral disease amenable to antiviral therapy. Appropriate preventive strategies like influenza vaccination also need to be employed routinely.

Procalcitonin to guide antibiotic administration in COPD exacerbations: a meta-analysis

Challenges in the differentiation of the aetiology of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have led to significant overuse of antibiotics. Serum procalcitonin, released in response to bacterial infections, but not viral infections, could possibly identify AECOPD requiring antibiotics. In this meta-analysis we assessed the clinical effectiveness of procalcitonin-based protocols to initiate or discontinue antibiotics in patients presenting with AECOPD.Based on a prospectively registered protocol, we reviewed the literature and selected randomised or quasi-randomised trials comparing procalcitonin-based protocols to initiate or discontinue antibiotics versus standard care in AECOPD. We followed Cochrane and GRADE (Grading of Recommendations, Assessment, Development and Evaluation) guidance to assess risk of bias, quality of evidence and to perform meta-analyses.We included eight trials evaluating 1062 patients with AECOPD. Procalcitonin-based protocols decreased antibiotic prescription (relative risk (RR) 0.56, 95% CI 0.43-0.73) and total antibiotic exposure (mean difference (MD) -3.83, 95% CI (-4.32--3.35)), without affecting clinical outcomes such as rate of treatment failure (RR 0.81, 0.62-1.06), length of hospitalisation (MD -0.76, -1.95-0.43), exacerbation recurrence rate (RR 0.96, 0.69-1.35) or mortality (RR 0.99, 0.58-1.69). However, the quality of the available evidence is low to moderate, because of methodological limitations and small overall study population.Procalcitonin-based protocols appear to be clinically effective; however, confirmatory trials with rigorous methodology are required.

Extracellular Vesicles in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is characterized by the progression of irreversible airflow limitation and is a leading cause of morbidity and mortality worldwide. Although several crucial mechanisms of COPD pathogenesis have been studied, the precise mechanism remains unknown. Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, are released from almost all cell types and are recognized as novel cell–cell communication tools. They have been shown to carry and transfer a wide variety of molecules, such as microRNAs, messenger RNAs, and proteins, which are involved in physiological functions and the pathology of various diseases. Recently, EVs have attracted considerable attention in pulmonary research. In this review, we summarize the recent findings of EV-mediated COPD pathogenesis. We also discuss the potential clinical usefulness of EVs as biomarkers and therapeutic agents for the treatment of COPD.

Precision respiratory medicine and the microbiome

A decade of rapid technological advances has provided an exciting opportunity to incorporate information relating to a range of potentially important disease determinants in the clinical decision-making process. Access to highly detailed data will enable respiratory medicine to evolve from one-size-fits-all models of care, which are associated with variable clinical effectiveness and high rates of side-effects, to precision approaches, where treatment is tailored to individual patients. The human microbiome has increasingly been recognised as playing an important part in determining disease course and response to treatment. Its inclusion in precision models of respiratory medicine, therefore, is essential. Analysis of the microbiome provides an opportunity to develop novel prognostic markers for airways disease, improve definition of clinical phenotypes, develop additional guidance to aid treatment selection, and increase the accuracy of indicators of treatment effect. In this Review we propose that collaboration between researchers and clinicians is needed if respiratory medicine is to replicate the successes of precision medicine seen in other clinical specialties.