Role of infections

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Influenza and pneumococcal vaccination in patients with COPD from 3 French cohorts: Insufficient coverage and associated factors

BACKGROUND

Low vaccination rates against influenza and Streptococcus (S.) pneumoniae infections in COPD could impair outcomes. Understanding underlying factors could help improving implementation.

OBJECTIVES

To describe vaccination rates at inclusion in COPD cohorts and analyze associated factors.

METHODS

Between 2012 and 2018, 5927 patients with sufficient data available were recruited in 3 French COPD cohorts (2566 in COLIBRI-COPD, 2653 in PALOMB and 708 in Initiatives BPCO). Data at inclusion were pooled to describe vaccination rates and analyze associated factors.

RESULTS

Mean age was 66 years, 34 % were women, 35 % were current smokers, mean FEV1 was 58 % predicted, 22 % reported ≥2 exacerbations in the year prior to inclusion, mMRC dyspnea grade was ≥2 in 59 %, 52 % had cardiovascular comorbidities and 9 % a history of asthma. Vaccinations rates in the year prior to study entry were 34.4 % for influenza + S. pneumoniae, 17.5 % for influenza alone and 8.9 % for S. pneumoniae alone. In multivariate analyses, influenza vaccination rate was greater in older age, smoking status, low FEV1, exacerbation history, mMRC dyspnea>2, asthma history, hypertension, diabetes mellitus, and the year of inclusion. SP vaccination was associated with type of practice of the respiratory physician, age, smoking status, FEV1, exacerbation history, dyspnea grade, asthma history and the year of inclusion.

CONCLUSION

Rates of vaccination against influenza and S. pneumoniae infection at inclusion in COPD cohorts remain insufficient and vaccination appears restricted to patients with specific features especially regarding severity and comorbidities, which is not consistent with current recommendations.

Cigarette smoke-induced dysbiosis: comparative analysis of lung and intestinal microbiomes in COPD mice and patients

BACKGROUND

The impact of cigarette smoke (CS) on lung diseases and the role of microbiome dysbiosis in chronic obstructive pulmonary disease (COPD) have been previously reported; however, the relationships remain unclear.

METHODS

Our research examined the effects of 20-week cigarette smoke (CS) exposure on the lung and intestinal microbiomes in C57BL/6JNarl mice, alongside a comparison with COPD patients' intestinal microbiome data from a public dataset.

RESULTS

The study found that CS exposure significantly decreased forced vital capacity (FVC), thickened airway walls, and induced emphysema. Increased lung damage was observed along with higher lung keratinocyte chemoattractant (KC) levels by CS exposure. Lung microbiome analysis revealed a rise in Actinobacteriota, while intestinal microbiome showed significant diversity changes, indicating dysbiosis. Principal coordinate analysis highlighted distinct intestinal microbiome compositions between control and CS-exposed groups. In the intestinal microbiome, notable decreases in Patescibacteria, Campilobacterota, Defferibacterota, Actinobacteriota, and Desulfobacterota were observed. We also identified correlations between lung function and dysbiosis in both lung and intestinal microbiomes. Lung interleukins, interferon-ɣ, KC, and 8-isoprostane levels were linked to lung microbiome dysbiosis. Notably, dysbiosis patterns in CS-exposed mice were similar to those in COPD patients, particularly of Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 4 patients. This suggests a systemic impact of CS exposure.

CONCLUSION

In summary, CS exposure induces significant dysbiosis in lung and intestinal microbiomes, correlating with lung function decline and injury. These results align with changes in COPD patients, underscoring the important role of microbiome in smoke-related lung diseases.

A Systematic Review of the Pulmonary Microbiome in Patients with Acute Exacerbation COPD Requiring ICU Admission

Background: Chronic obstructive pulmonary disease (COPD) is a major health concern. Acute exacerbations (AECOPD) may require intensive care unit (ICU) admission and mechanical ventilation. Acute infections and chronic colonization of the respiratory system are known to precipitate AECOPD. Detailed knowledge of the respiratory microbiome could lead to effective treatment and prevention of exacerbations. Objective: The aim of this review is to summarize the available evidence on the respiratory microbiome of patients with a severe AECOPD requiring mechanical ventilation and intensive care admission. Methods: A systematic literature search was conducted to identify the published papers until January 2023. The collected data were then subjected to qualitative analysis. After the first analysis, a secondary focused review of the most recent publications studying the relationship between microbiome and mortality in AECOPD was performed. Results: Out of 120 screened articles six articles were included in this review. Potentially pathogenic microorganisms (PPMs) were identified in 30% to 72% of the patients with community-acquired bacteria, gram-negative enteric bacilli, Stenotrophomonas and Pseudomonas being the most frequently isolated. During hospitalization, 21% of patients experienced colonization by PPMs. Adequate antimicrobial therapy resulted in the eradication of 77% of the identified PPMs. However, 24% of the bacteria displayed multi-drug resistance leading to prolonged or failure of eradication. Conclusion: PPMs are prevalent in a significant proportion of patients experiencing an AECOPD. The most identified PPMs include community-acquired pathogens and gram-negative enteric bacilli. Notably, no differences in mortality or duration of ventilation were observed between patients with and without isolated PPMs. However, the included studies did not investigate the virome of the patients, which may influence the microbiome and the outcome of infection. Therefore, further research is essential to comprehensively investigate the complete microbial and viral composition of the lower respiratory system in COPD patients admitted to the ICU.

Inhaled corticosteroids and risk of lower respiratory tract infection with Moraxella catarrhalis in patients with chronic obstructive pulmonary disease

BACKGROUND

Use of inhaled corticosteroids (ICS) is common in patients with chronic obstructive pulmonary disease (COPD) and has been associated with an increased risk of pneumonia. Moraxella catarrhalis is one of the most common bacterial causes of infectious exacerbation in COPD. Currently, to our knowledge, no studies have investigated if ICS increases the risk of lower respiratory tract infection with M. catarrhalis in patients with COPD.

OBJECTIVE

To investigate if accumulated ICS use in patients with COPD, is associated with a dose-dependent risk of infection with M. catarrhalis.

METHODS

This observational cohort study included 18 870 persons with COPD who were registered in The Danish Register of COPD. Linkage to several nationwide registries was performed.Exposure to ICS was determined by identifying all prescriptions for ICS, redeemed within 365 days prior to study entry. Main outcome was a lower respiratory tract sample positive for M. catarrhalis. For the main analysis, a Cox multivariate regression model was used.We defined clinical infection as admission to hospital and/or a redeemed prescription for a relevant antibiotic, within 7 days prior to 14 days after the sample was obtained.

RESULTS

We found an increased, dose-dependent, risk of a lower respiratory tract sample with M. catarrhalis among patients who used ICS, compared with non-users. For low and moderate doses of ICS HR was 1.65 (95% CI 1.19 to 2.30, p=0.003) and 1.82 (95% CI 1.32 to 2.51, p=0.0002), respectively. In the group of patients with highest ICS exposure, the HR of M. catarrhalis was 2.80 (95% CI 2.06 to 3.82, p<0.0001). Results remained stable in sensitivity analyses. 87% of patients fulfilled the criteria for clinical infection, and results remained unchanged in this population.

CONCLUSION

Our study shows a dose-dependent increased risk of infection with M. catarrhalis associated to ICS exposure.

The dynamic lung microbiome in health and disease

New methods and technologies within the field of lung biology are beginning to shed new light into the microbial world of the respiratory tract. Long considered to be a sterile environment, it is now clear that the human lungs are frequently exposed to live microbes and their by-products. The nature of the lung microbiome is quite distinct from other microbial communities inhabiting our bodies such as those in the gut. Notably, the microbiome of the lung exhibits a low biomass and is dominated by dynamic fluxes of microbial immigration and clearance, resulting in a bacterial burden and microbiome composition that is fluid in nature rather than fixed. As our understanding of the microbial ecology of the lung improves, it is becoming increasingly apparent that certain disease states can disrupt the microbial-host interface and ultimately affect disease pathogenesis. In this Review, we provide an overview of lower airway microbial dynamics in health and disease and discuss future work that is required to uncover novel therapeutic targets to improve lung health.

Effects of antibiotics and metals on lung and intestinal microbiome dysbiosis after sub-chronic lower-level exposure of air pollution in ageing rats

We investigated the effects of antibiotics, drugs, and metals on lung and intestinal microbiomes after sub-chronic exposure of low-level air pollution in ageing rats. Male 1.5-year-old Fischer 344 ageing rats were exposed to low-level traffic-related air pollution via whole-body exposure system for 3 months with/without high-efficiency particulate air (HEPA) filtration (gaseous vs. particulate matter with aerodynamic diameter of ≤2.5 µm (PM_2.5) pollution). Lung functions, antibiotics, drugs, and metals in lungs were examined and linked to lung and fecal microbiome analyses by high-throughput sequencing analysis of 16 s ribosomal (r)DNA. Rats were exposed to 8.7 μg/m³ PM_2.5, 10.1 ppb NO₂, 1.6 ppb SO₂, and 23.9 ppb O₃ in average during the study period. Air pollution exposure decreased forced vital capacity (FVC), peak expiratory flow (PEF), forced expiratory volume in 20 ms (FEV₂₀), and FEF at 25∼75% of FVC (FEF_25-75). Air pollution exposure increased antibiotics and drugs (benzotriazole, methamphetamine, methyl-1 H-benzotriazole, ketamine, ampicillin, ciprofloxacin, pentoxifylline, erythromycin, clarithromycin, ceftriaxone, penicillin G, and penicillin V) and altered metals (V, Cr, Cu, Zn, and Ba) levels in lungs. Fusobacteria and Verrucomicrobia at phylum level were increased in lung microbiome by air pollution, whereas increased alpha diversity, Bacteroidetes and Proteobacteria and decreased Firmicutes at phylum level were occurred in intestinal microbiome. Lung function decline was correlated with increasing antibiotics, drugs, and metals in lungs as well as lung and intestinal microbiome dysbiosis. The antibiotics, drugs, and Cr, Co, Ca, and Cu levels in lung were correlated with lung and intestinal microbiome dysbiosis. The lung microbiome was correlated with intestinal microbiome at several phylum and family levels after air pollution exposure. Our results revealed that antibiotics, drugs, and metals in the lung caused lung and intestinal microbiome dysbiosis in ageing rats exposed to air pollution, which may lead to lung function decline.

Chronic Obstructive Pulmonary Disease and Lung Cancer: A Review for Clinicians

Chronic obstructive pulmonary disease (COPD) and lung cancer are common global causes of morbidity and mortality. Because both diseases share several predisposing risks, the 2 diseases may occur concurrently in susceptible individuals. The diagnosis of COPD has important implications for the diagnostic approach and treatment options if lesions concerning for lung cancer are identified during screening. Importantly, the presence of COPD has significant implications on prognosis and management of patients with lung cancer. In this monograph, we review the mechanistic linkage between lung cancer and COPD, the impact of lung cancer screening on patients at risk, and the implications of the presence of COPD on the approach to the diagnosis and treatment of lung cancer. This manuscript succinctly reviews the epidemiology and common pathogenetic factors for the concurrence of COPD and lung cancer. Importantly for the clinician, it summarizes the indications, benefits, and complications of lung cancer screening in patients with COPD, and the assessment of risk factors for patients with COPD undergoing consideration of various treatment options for lung cancer.

Development and multimodal characterization of an elastase-induced emphysema mouse disease model for the COPD frequent bacterial exacerbator phenotype

Chronic obstructive pulmonary disease (COPD) patients undergo infectious exacerbations whose frequency identifies a clinically meaningful phenotype. Mouse models have been mostly used to separately study both COPD and the infectious processes, but a reliable model of the COPD frequent exacerbator phenotype is still lacking. Accordingly, we first established a model of single bacterial exacerbation by nontypeable Haemophilus influenzae (NTHi) infection on mice with emphysema-like lesions. We characterized this single exacerbation model combining both noninvasive in vivo imaging and ex vivo techniques, obtaining longitudinal information about bacterial load and the extent of the developing lesions and host responses. Bacterial load disappeared 48 hours post-infection (hpi). However, lung recovery, measured using tests of pulmonary function and the disappearance of lung inflammation as revealed by micro-computed X-ray tomography, was delayed until 3 weeks post-infection (wpi). Then, to emulate the frequent exacerbator phenotype, we performed two recurrent episodes of NTHi infection on the emphysematous murine lung. Consistent with the amplified infectious insult, bacterial load reduction was now observed 96 hpi, and lung function recovery and disappearance of lesions on anatomical lung images did not happen until 12 wpi. Finally, as a proof of principle of the use of the model, we showed that azithromycin successfully cleared the recurrent infection, confirming this macrolide utility to ameliorate infectious exacerbation. In conclusion, we present a mouse model of recurrent bacterial infection of the emphysematous lung, aimed to facilitate investigating the COPD frequent exacerbator phenotype by providing complementary, dynamic information of both infectious and inflammatory processes.

Inhaled Corticosteroids and the Lung Microbiome in COPD

The Global Initiative for Chronic Obstructive Lung Disease 2021 Report recommends inhaled corticosteroid (ICS)-containing regimens as part of pharmacological treatment in patients with chronic obstructive lung disease (COPD) and frequent exacerbations, particularly with eosinophilic inflammation. However, real-world studies reveal overprescription of ICS in COPD, irrespective of disease presentation and inflammatory endotype, leading to increased risk of side effects, mainly respiratory infections. The optimal use of ICS in COPD therefore remains an area of intensive research, and additional biomarkers of benefit and risk are needed. Although the interplay between inflammation and infection in COPD is widely acknowledged, the role of the microbiome in shaping lower airway inflammation has only recently been explored. Next-generation sequencing has revealed that COPD disease progression and exacerbation frequency are associated with changes in the composition of the lung microbiome, and that the immunosuppressive effects of ICS can contribute to potentially deleterious airway microbiota changes by increasing bacterial load and the abundance of potentially pathogenic taxa such as Streptococcus and Haemophilus. Here, we explore the relationship between microbiome, inflammation, ICS use and disease phenotype. This relationship may inform the benefit:risk assessment of ICS use in patients with COPD and lead to more personalised pharmacological management.

Biomarkers for Comorbidities Modulate the Activity of T-Cells in COPD

In smoking-induced chronic obstructive pulmonary disease (COPD), various comorbidities are linked to systemic inflammation and infection-induced exacerbations. The underlying mechanisms are unclear but might provide therapeutic targets. T-cell activity is central in systemic inflammation and for infection-defense mechanisms and might be influenced by comorbidities. Hypothesis: Circulating biomarkers of comorbidities modulate the activity of T-cells of the T-helper type 1 (Th1) and/or T-cytotoxic type 1 (Tc1). T-cells in peripheral blood mononuclear cells (PBMCs) from non-smokers (NS), current smokers without COPD (S), and COPD subjects (total n = 34) were ex vivo activated towards Th1/Tc1 and were then stimulated with biomarkers for metabolic and/or cardiovascular comorbidities (Brain Natriuretic Peptide, BNP; chemokine (C-C motif) ligand 18, CCL18; C-X3-C motif chemokine ligand 1, CX3CL1; interleukin-18, IL-18) or for asthma- and/or cancer-related comorbidities (CCL22; epidermal growth factor, EGF; IL-17; periostin) each at 10 or 50 ng/mL. The Th1/Tc1 activation markers interferon-γ (IFNγ), tumor necrosis factor-α (TNFα), and granulocyte-macrophage colony-stimulating factor (GM-CSF) were analyzed in culture supernatants by Enzyme-Linked Immunosorbent Assay (ELISA). Ex-vivo activation induced IFNγ and TNFα without differences between the groups but GM-CSF more in S vs. NS. At 10 ng/mL, the different biomarkers increased or reduced the T-cell activation markers without a clear trend for one direction in the different categories of comorbidities or for the different T-cell activation markers. At 50 ng/mL, there was a clear shift towards suppressive effects, particularly for the asthma— and cancer-related biomarkers and in cells of S and COPD. Comorbidities might suppress T-cell immunity in COPD. This could explain the association of comorbidities with frequent exacerbations.

Clinical relevance of emphysema in patients hospitalized with community-acquired pneumonia: Clinical features and prognosis

INTRODUCTION

Few studies have investigated the influence of emphysema on clinical features of patients presenting with community-acquired pneumonia (CAP).

OBJECTIVES

The aim of this study was to examine the clinical and microbiological features of patients with both CAP and emphysema.

METHODS

This retrospective study included patients with CAP who underwent computed tomography (CT) scan at the time of presentation. Patients were allocated into emphysema and control groups, and clinical variables were compared between the two groups. The emphysema group was further divided into three subgroups (mild, moderate, and severe) according to the extent of emphysema on CT scan. The clinical variables of each subgroup were compared with the control group.

RESULTS

Of 1676 patients, 431 patients (25.7%) were classified into the emphysema group. CAP patients with emphysema were more likely to have a high CURB-65 score and pneumonia severity index and a lower incidence of complicated parapneumonic effusion or empyema. The emphysema group exhibited longer hospital stay. In addition, 30-day mortality in the severe emphysema group was significantly higher compared with the control group. As etiological agents, Streptococcus pneumoniae, Pseudomonas aeruginosa, Enterobacteriaceae, and multidrug-resistant pathogens were significantly more common in the emphysema group compared with the control group.

CONCLUSIONS

The presence of emphysema in CAP patients was associated with a more severe form of CAP, a longer hospital stay, and a lower incidence of complicated parapneumonic effusion or empyema. Moreover, CAP patients with severe emphysema exhibited higher 30-day mortality than those without emphysema.

Consensus Document on the Diagnosis and Treatment of Chronic Bronchial Infection in Chronic Obstructive Pulmonary Disease

Although the chronic presence of microorganisms in the airways of patients with stable chronic obstructive pulmonary disease (COPD) confers a poor outcome, no recommendations have been established in disease management guidelines on how to diagnose and treat these cases. In order to guide professionals, the Spanish Society of Pulmonology and Thoracic Surgery (SEPAR) has prepared a document which aims to answer questions on the clinical management of COPD patients in whom microorganisms are occasionally or habitually isolated. Since the available scientific evidence is too heterogeneous to use in the creation of a clinical practice guideline, we have drawn up a document based on existing scientific literature and clinical experience, addressing the definition of different clinical situations and their diagnosis and management. The text was drawn up by consensus and approved by a large group of respiratory medicine experts with extensive clinical and scientific experience in the field, and has been endorsed by the SEPAR Scientific Committee.

Pneumonic versus Nonpneumonic Exacerbations of Chronic Obstructive Pulmonary Disease

Patients with chronic obstructive pulmonary disease (COPD) often suffer acute exacerbations (AECOPD) and community-acquired pneumonia (CAP), named nonpneumonic and pneumonic exacerbations of COPD, respectively. Abnormal host defense mechanisms may play a role in the specificity of the systemic inflammatory response. Given the association of this aspect to some biomarkers at admission (e.g., C-reactive protein), it can be used to help to discriminate AECOPD and CAP, especially in cases with doubtful infiltrates and advanced lung impairment. Fever, sputum purulence, chills, and pleuritic pain are typical clinical features of CAP in a patient with COPD, whereas isolated dyspnea at admission has been reported to predict AECOPD. Although CAP may have a worse outcome in terms of mortality (in hospital and short term), length of hospitalization, and early readmission rates, this has only been confirmed in a few prospective studies. There is a lack of methodologically sound research confirming the impact of severe AECOPD and COPD + CAP. Here, we review studies reporting head-to-head comparisons between AECOPD and CAP + COPD in hospitalized patients. We focus on the epidemiology, risk factors, systemic inflammatory response, clinical and microbiological characteristics, outcomes, and treatment approaches. Finally, we briefly discuss some proposals on how we should orient research in the future.

Haemophilus influenzae Glucose Catabolism Leading to Production of the Immunometabolite Acetate Has a Key Contribution to the Host Airway-Pathogen Interplay

Chronic obstructive pulmonary disease (COPD) is characterized by abnormal inflammatory responses and impaired airway immunity, which provides an opportunistic platform for nontypeable Haemophilus influenzae (NTHi) infection. Clinical evidence supports that the COPD airways present increased concentrations of glucose, which may facilitate proliferation of pathogenic bacteria able to use glucose as a carbon source. NTHi metabolizes glucose through respiration-assisted fermentation, leading to the excretion of acetate, formate, and succinate. We hypothesized that such specialized glucose catabolism may be a pathoadaptive trait playing a pivotal role in the NTHi airway infection. To find out whether this is true, we engineered and characterized bacterial mutant strains impaired to produce acetate, formate, or succinate by inactivating the ackA, pflA, and frdA genes, respectively. While the inactivation of the pflA and frdA genes only had minimal physiological effects, the inactivation of the ackA gene affected acetate production and led to reduced bacterial growth, production of lactate under low oxygen tension, and bacterial attenuation in vivo. Moreover, bacterially produced acetate was able to stimulate the expression of inflammatory genes by cultured airway epithelial cells. These results back the notion that the COPD lung supports NTHi growth on glucose, enabling production of fermentative end products acting as immunometabolites at the site of infection. Thus, glucose catabolism may contribute not only to NTHi growth but also to bacterially driven airway inflammation. This information has important implications for developing nonantibiotic antimicrobials, given that airway glucose homeostasis modifying drugs could help prevent microbial infections associated with chronic lung disease.

How may we improve clinical outcomes for patients hospitalized with acute exacerbations of chronic obstructive pulmonary disease? A narrative review about possible therapeutic and preventive strategies

Introduction: In a subset of chronic obstructive pulmonary disease (COPD)patients the course of the disease is complicated by a severe acute exacerbations (AECOPD) that may require hospitalization, at which time negative outcomes may occur up to 30 days after discharge. Several predictors of negative outcomes have been documented.Areas covered: We considered five negative outcomes related to patients hospitalized with AECOPD: treatment failure, noninvasive mechanical ventilation (NIMV) failure, prolonged length of hospital stay (LHS), short-term mortality (≤ 90 days from admission and including the in-hospital mortality), and early readmission (≤30 days from discharge). Possible therapeutic and preventive strategies to improve these outcomes are outlined and discussed.Expert opinion: Several strategies have been proposed to improve outcomes. Among these, steroid or antibiotic use may reduce the risks of treatment failure or of prolonged hospital stay. We note that operator-related factors may influence the outcome of NIMV. However, little has been documented about the short-term mortality or early readmission rates. In general, few interventions consistently improve negative outcomes and prognosis of AECOPD.

Preclinical Evaluation of the Antimicrobial-Immunomodulatory Dual Action of Xenohormetic Molecules against Haemophilus influenzae Respiratory Infection

Chronic obstructive pulmonary disease (COPD) is characterized by abnormal inflammation and impaired airway immunity, providing an opportunistic platform for nontypeable Haemophilus influenzae (NTHi) infection. In this context, therapies targeting not only overactive inflammation without significant adverse effects, but also infection are of interest. Increasing evidence suggests that polyphenols, plant secondary metabolites with anti-inflammatory and antimicrobial properties, may be protective. Here, a Cistus salviifolius plant extract containing quercetin, myricetin, and punicalagin was shown to reduce NTHi viability. Analysis of these polyphenols revealed that quercetin has a bactericidal effect on NTHi, does not display synergies, and that bacteria do not seem to develop resistance. Moreover, quercetin lowered NTHi airway epithelial invasion through a mechanism likely involving inhibition of Akt phosphorylation, and reduced the expression of bacterially-induced proinflammatory markers il-8, cxcl-1, il-6, pde4b, and tnfα. We further tested quercetin’s effect on NTHi murine pulmonary infection, showing a moderate reduction in bacterial counts and significantly reduced expression of proinflammatory genes, compared to untreated mice. Quercetin administration during NTHi infection on a zebrafish septicemia infection model system showed a bacterial clearing effect without signs of host toxicity. In conclusion, this study highlights the therapeutic potential of the xenohormetic molecule quercetin against NTHi infection.

Chronic obstructive pulmonary disease (COPD) and lung cancer: common pathways for pathogenesis

Chronic obstructive pulmonary disease (COPD) and lung cancer comprise the leading causes of lung disease-related mortality worldwide. Exposure to tobacco smoke is a mutual aetiology underlying the two diseases, accounting for almost 90% of cases. There is accumulating evidence supporting the role of immune dysfunction, the lung microbiome, extracellular vesicles and underlying genetic susceptibility in the development of COPD and lung cancer. Further, epigenetic factors, involving DNA methylation and microRNA expression, have been implicated in both diseases. Chronic inflammation is a key feature of COPD and could be a potential driver of lung cancer development. Using next generation technologies, further studies investigating the genomics, epigenetics and gene-environment interaction in key molecular pathways will continue to elucidate the pathogenic mechanisms underlying the development of COPD and lung cancer, and contribute to the development of novel diagnostic and prognostic tools for early intervention and personalised therapeutic strategies.

Future Research Directions in Pneumonia. NHLBI Working Group Report

Pneumonia is a complex pulmonary disease in need of new clinical approaches. Although triggered by a pathogen, pneumonia often results from dysregulations of host defense that likely precede infection. The coordinated activities of immune resistance and tissue resilience then dictate whether and how pneumonia progresses or resolves. Inadequate or inappropriate host responses lead to more severe outcomes such as acute respiratory distress syndrome and to organ dysfunction beyond the lungs and over extended time frames after pathogen clearance, some of which increase the risk for subsequent pneumonia. Improved understanding of such host responses will guide the development of novel approaches for preventing and curing pneumonia and for mitigating the subsequent pulmonary and extrapulmonary complications of pneumonia. The NHLBI assembled a working group of extramural investigators to prioritize avenues of host-directed pneumonia research that should yield novel approaches for interrupting the cycle of unhealthy decline caused by pneumonia. This report summarizes the working group's specific recommendations in the areas of pneumonia susceptibility, host response, and consequences. Overarching goals include the development of more host-focused clinical approaches for preventing and treating pneumonia, the generation of predictive tools (for pneumonia occurrence, severity, and outcome), and the elucidation of mechanisms mediating immune resistance and tissue resilience in the lung. Specific areas of research are highlighted as especially promising for making advances against pneumonia.

Airway infection with Nontypeable Haemophilus influenzae is more rapidly eradicated in vitamin D deficient mice

Chronic obstructive pulmonary disease (COPD), which is characterized by an excessive inflammatory response of the airways, is often complicated by exacerbations. Vitamin D deficiency has been associated with an increased risk for COPD and may predispose COPD patients to a higher exacerbation rate, particularly during smoking. In the current study, we investigated the effect of vitamin D deficiency and cigarette smoke (CS)-exposure on lung inflammation and bacterial clearance after an acute infection with Nontypeable Haemophilus influenzae (NTHi). Vitamin D deficient or sufficient mice were exposed to nose-only CS or ambient air for 6 weeks and oropharyngeally instilled with 10⁶ NTHi. Residual viable NTHi were measured at different time points post-infection. Mechanisms of bacterial clearance (e.g. phagocytosis, pattern recognition receptors, antimicrobial peptides, surfactant proteins and mucin) and lung remodeling (e.g. metalloproteinases, MMP's) were assessed. Although smoking resulted in reduced phagocytosis capacity of macrophages and neutrophils, bacterial clearance was similar to control mice. By contrast and independent of smoking, bacterial clearance was significantly accelerated in vitamin D deficient mice already from 24 h post-infection (p = 0.0087). This faster and complete eradication was associated with a more rapid resolution of cytokines and neutrophils 72 h post-infection and dominated by an upregulation of cathelicidin-related antimicrobial peptide (CRAMP) mRNA during infection (p = 0.026). However, vitamin D deficiency also resulted in more MMP12 protein in broncho-alveolar lavage and a shift in mRNA expression of MMP12/TIMP1 (p = 0.038) and MMP9/TIMP1 (p = 0.024) ratio towards more protease activity. Overall, vitamin D deficient mice resolved NTHi infection faster with a faster resolution of local lung inflammation, possibly through upregulation of CRAMP. This was associated with a disruption of the protease/anti-protease balance, which may potentially scale towards a higher extracellular matrix breakdown.

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.

Acute Moraxella catarrhalis Airway Infection of Chronically Smoke-Exposed Mice Increases Mechanisms of Emphysema Development: A Pilot Study

In chronic obstructive pulmonary disease (COPD), acute exacerbations and emphysema development are characteristics for disease pathology. COPD is complicated by infectious exacerbations with acute worsening of respiratory symptoms with Moraxella catarrhalis as one of the most frequent pathogens. Although cigarette smoke (CS) is the primary risk factor, additional molecular mechanisms for emphysema development induced by bacterial infections are incompletely understood. We investigated the impact of M. catarrhalis on emphysema development in CS exposed mice and asked whether an additional infection would induce a solubilization of pro-apoptotic and pro-inflammatory endothelial monocyte-activating-protein-2 (EMAPII) to exert its activities in the pulmonary microvas-culature and other parts of the lungs not exposed directly to CS.

Mice were exposed to smoke (6 or 9 months) and/or infected with M. catarrhalis. Lungs, bronchoalveolar lavage fluid (BALF), and plasma were analyzed.

CS exposure reduced ciliated area, caused rarefaction of the lungs, and induced apoptosis. EMAPII was increased independent of prior smoke exposure in BALF of infected mice. Importantly, acute M. catarrhalis infection increased release of matrixmetalloproteases-9 and -12, which are involved in emphysema development and comprise a mechanism of EMAPII release.

Our data suggest that acute M. catarrhalis infection represents an independent risk factor for emphysema development in smoke-exposed mice.

The Interplay Between Immune Response and Bacterial Infection in COPD: Focus Upon Non-typeable Haemophilus influenzae

Chronic obstructive pulmonary disease (COPD) is a debilitating respiratory disease and one of the leading causes of morbidity and mortality worldwide. It is characterized by persistent respiratory symptoms and airflow limitation due to abnormalities in the lower airway following consistent exposure to noxious particles or gases. Acute exacerbations of COPD (AECOPD) are characterized by increased cough, purulent sputum production, and dyspnea. The AECOPD is mostly associated with infection caused by common cold viruses or bacteria, or co-infections. Chronic and persistent infection by non-typeable Haemophilus influenzae (NTHi), a Gram-negative coccobacillus, contributes to almost half of the infective exacerbations caused by bacteria. This is supported by reports that NTHi is commonly isolated in the sputum from COPD patients during exacerbations. Persistent colonization of NTHi in the lower airway requires a plethora of phenotypic adaptation and virulent mechanisms that are developed over time to cope with changing environmental pressures in the airway such as host immuno-inflammatory response. Chronic inhalation of noxious irritants in COPD causes a changed balance in the lung microbiome, abnormal inflammatory response, and an impaired airway immune system. These conditions significantly provide an opportunistic platform for NTHi colonization and infection resulting in a "vicious circle." Episodes of large inflammation as the consequences of multiple interactions between airway immune cells and NTHi, accumulatively contribute to COPD exacerbations and may result in worsening of the clinical status. In this review, we discuss in detail the interplay and crosstalk between airway immune residents and NTHi, and their effect in AECOPD for better understanding of NTHi pathogenesis in COPD patients.

Clinical features, bacteriology of endotracheal aspirates and treatment outcomes of patients with chronic obstructive pulmonary disease and community-acquired pneumonia in an intensive care unit in Taiwan with an emphasis on eosinophilia versus non-eosinophilia: a retrospective case-control study

OBJECTIVES

The clinical implications of blood eosinophil level in patients with chronic obstructive pulmonary disease (COPD) and community-acquired pneumonia (CAP) requiring invasive mechanical ventilation (IMV) and intensive care unit (ICU) admission are still unknown. Thus, this study aimed to compare the features of such patients with and without blood eosinophilia.

DESIGN

This was a retrospective case-control study.

SETTING

An ICU of a medical centre in central Taiwan.

PARTICIPANTS

A total of 262 patients with COPD and CAP requiring IMV and ICU admission.

RESULTS

Of all participants (n=262), 32 (12.2%) had an eosinophil percentage (EP) >2% and 169 (64.5%) had an absolute eosinophil count (AEC) >300 cells/µL. Regardless of whether 2% or 300 cells/µL was used as a cut-off value, the eosinophilia group were slightly older (years) (82.9±5.4 vs 78.1±9.1, p=0.000 and 79.2±8.4 vs 77.6±9.6, p=0.246, respectively), and had a higher forced expiratory volume in 1 s/forced vital capacity (%) (56.0±8.0 vs 51.3±11.6, p=0.005 and 53.1±11.2 vs 49.5±11.2, p=0.013, respectively), less severe spirometric classification (p=0.008 and p=0.001, respectively), and lower white cell count 109/L (8.8±3.2 vs 11.1±4.9, p=0.009 and 10.3±4.4 vs 11.8±5.3, p=0.017, respectively) than the non-eosinophilia group. The bacteriology of endotracheal aspirates showed that Pseudomonas aeruginosa and other gram-negative bacilli were the most common organisms in all study groups. Participants with an EP >2% had a shorter ICU length of stay (OR=12.13, p=0.001) than those with an EP ≤2%, while an AEC >300 cells/µL was not associated with any in-ICUoutcomes.

CONCLUSIONS

The results of this study have significant clinical implications and should be considered when making treatment decisions for the management of patients with COPD and CAP requiring IMV and ICU admission.

Current Status of Community-Acquired Pneumonia in Patients with Chronic Obstructive Pulmonary Disease

OBJECTIVE

Worldwide, community-acquired pneumonia (CAP) is a common infection that occurs in older adults, who may have pulmonary comorbidities, including chronic obstructive pulmonary disease (COPD). Although there have been clinical studies on the coexistence of CAP with COPD, there remain some controversial findings. This review presents the current status of COPD in CAP patients, including the disease burden, clinical characteristics, risk factors, microbial etiology, and antibiotic treatment.

DATA SOURCES

A literature review included full peer-reviewed publications up to January 2018 derived from the PubMed database, using the keywords "community-acquired pneumonia" and "chronic obstructive pulmonary disease".

STUDY SELECTION

Papers in English were reviewed, with no restriction on study design.

RESULTS

COPD patients who are treated with inhaled corticosteroids are at an increased risk of CAP and have a worse prognosis, but data regarding the increased mortality remains unclear. Although Streptococcus pneumoniae is still regarded as the most common bacteria isolated from patients with CAP and COPD, Pseudomonas aeruginosa is also important, and physicians should pay close attention to the occurrence of antimicrobial resistance, particularly in these two organisms.

CONCLUSIONS

COPD is a common and important predisposing comorbidity in patients who develop CAP. COPD often aggravates the clinical symptoms of patients with CAP, complicating treatment, but generally does not appear to affect prognosis.

Nano-based rescue of dysfunctional autophagy in chronic obstructive lung diseases

INTRODUCTION

ΔF508-CFTR (cystic fibrosis transmembrane conductance regulator) is a common CF-mutation that is known to induce oxidative-inflammatory stress through activation of reactive oxygen species (ROS), which induces autophagy-impairment resulting in accumulation of CFTR in aggresome-bodies. Cysteamine, the reduced form of cystamine, is a FDA-approved drug that has anti-oxidant, anti-bacterial, and mucolytic properties. This drug has been shown in a recent clinical trial to decrease lung inflammation and improve lung function in CF patients by potentially restoring autophagy and allowing CFTR to be trafficked to the cell membrane. Areas covered: The delivery of cysteamine to airway epithelia of chronic subjects prerequisite the need for a delivery system to allow rescue of dysfunctional autophagy. Expert opinion: We anticipate based on our ongoing studies that PLGA-PEG- or Dendrimer-mediated cysteamine delivery could allow sustained airway delivery over standard cysteamine tablets or delay release capsules that are currently used for systemic treatment. In addition, proposed nano-based autophagy induction strategy can also allow rescue of cigarette smoke (CS) induced acquired-CFTR dysfunction seen in chronic obstructive pulmonary disease (COPD)-emphysema subjects. The CS induced acquired-CFTR dysfunction involves CFTR-accumulation in aggresome-bodies that can be rescued by an autophagy-inducing antioxidant drug, cysteamine. Moreover, chronic CS-exposure generates ROS that induces overall protein-misfolding and aggregation of ubiquitinated-proteins as aggresome-bodies via autophagy-impairment that can be also be resolved by treatment with autophagy-inducing antioxidant drug, cysteamine.

Metagenome and Metatranscriptome Profiling of Moderate and Severe COPD Sputum in Taiwanese Han Males

Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disorder characterized by the progressive obstruction of airflow and is currently the fourth leading cause of death in the world. The pathogenesis of COPD is thought to involve bacterial infections and inflammations. Owing to advancement in sequencing technology, evidence is emerging that supports an association between the lung microbiome and COPD. However, few studies have looked into the expression profile of the bacterial communities in the COPD lungs. In this study, we analyzed the sputum microbiome of four moderate and four severe COPD male patients both at the DNA and RNA level, using next generation sequencing technology. We found that bacterial composition determined by 16S rRNA gene sequencing may not directly translate to the set of actively expressing bacteria as defined by transcriptome sequencing. The two sequencing data agreed on Prevotella, Rothia, Neisseria, Porphyromonas, Veillonella, Fusobacterium and Streptococcus being among the most differentially abundant genera between the moderate and severe COPD samples, supporting their association with COPD severity. However, the two sequencing analyses disagreed on the relative abundance of these bacteria in the two COPD groups, implicating the importance of studying the actively expressing bacteria for enriching our understanding of COPD. Though we have described the metatranscriptome profiles of the lung microbiome in moderate and severe COPD, further investigations are required to determine the functional basis underlying the relationship between the microbial species in the lungs and pathogenesis of COPD.

Will chronic e-cigarette use cause lung disease?

Chronic tobacco smoking is a major cause of preventable morbidity and mortality worldwide. In the lung, tobacco smoking increases the risk of lung cancer, and also causes chronic obstructive pulmonary disease (COPD), which encompasses both emphysema and chronic bronchitis. E-cigarettes (E-Cigs), or electronic nicotine delivery systems, were developed over a decade ago and are designed to deliver nicotine without combusting tobacco. Although tobacco smoking has declined since the 1950s, E-Cig usage has increased, attracting both former tobacco smokers and never smokers. E-Cig liquids (e-liquids) contain nicotine in a glycerol/propylene glycol vehicle with flavorings, which are vaporized and inhaled. To date, neither E-Cig devices, nor e-liquids, are regulated by the Food and Drug Administration (FDA). The FDA has proposed a deeming rule, which aims to initiate legislation to regulate E-Cigs, but the timeline to take effect is uncertain. Proponents of E-Cigs say that they are safe and should not be regulated. Opposition is varied, with some opponents proposing that E-Cig usage will introduce a new generation to nicotine addiction, reversing the decline seen with tobacco smoking, or that E-Cigs generally may not be safe and will trigger diseases like tobacco. In this review, we shall discuss what is known about the effects of E-Cigs on the mammalian lung and isolated lung cells in vitro. We hope that collating this data will help illustrate gaps in the knowledge of this burgeoning field, directing researchers toward answering whether or not E-Cigs are capable of causing disease.

Fluoroquinolones versus β-Lactam/β-Lactamase Inhibitors in Outpatients with Chronic Obstructive Pulmonary Disease and Pneumonia: A Nationwide Population-Based Study

Background

Studies on the association between antibiotic treatment and outcomes in outpatients with chronic obstructive pulmonary disease (COPD) and pneumonia are scarce. This study aimed to evaluate the effectiveness of fluoroquinolones and β-lactam/β-lactamase inhibitors for pneumonia in COPD outpatients.

Methods

We conducted a retrospective cohort study and identified 4,851 episodes of pneumonia among COPD outpatients treated with fluoroquinolones or β-lactam/β-lactamase inhibitors from the Taiwan National Health Insurance Research Database during 2002–2011. Using the propensity score analysis, 1,296 pairs of episodes were matched for the demographic and clinical characteristics. The primary outcome was pneumonia/empyema-related hospitalization or emergency department (ED) visits, and the secondary outcomes were treatment failure, all-cause mortality and medical costs within 30 days.

Results

Compared with episodes treated with β-lactam/β-lactamase inhibitors, episodes treated with fluoroquinolones had similar clinical outcomes. The rates of pneumonia/empyema-related hospitalization or ED visits were 3.9% and 3.5% in the fluoroquinolone and β-lactam/β-lactamase inhibitor groups, respectively (adjusted hazard ratio [aHR], 1.11; 95% confidence interval [CI], 0.74–1.66). The percentage of treatment failure and all-cause mortality were 28.2% versus 31.3% (adjusted odds ratio, 0.86; 95% CI, 0.73–1.02) and 0.5% versus 0.4% (aHR, 1.40; 95% CI, 0.45–4.41) in the fluoroquinolone and β-lactam/β-lactamase inhibitor groups, respectively. The medical expenditures, including total medical costs (528 versus 455 US dollars) and pneumonia-related costs (202 vs. 155 USD) were also balanced between the two treatment groups (both P >0.05).

Conclusions

For pneumonia in COPD outpatients, fluoroquinolones were associated with similar clinical outcomes and medical expenditures compared with β-lactam/β-lactamase inhibitors.

Heterogeneity of chronic obstructive pulmonary disease exacerbations: a two-axes classification proposal

Exacerbations of chronic obstructive pulmonary disease (COPD) are clinically relevant events with therapeutic and prognostic implications. Yet, they are heterogeneous and can need different therapeutic strategies. In this Viewpoint, we propose an admittedly crude approach to a COPD exacerbation classification that might eventually help to define the most appropriate pharmacological treatment and clinical treatment setting for these patients. Our suggestion is to combine a pathobiological axis (biomarkers) to guide treatment decisions (use of antibiotics, steroids, or both) with a clinical axis (severity score) to decide the organisational context in which to optimally treat the patient. Needless to say, this proposal needs to be researched and eventually validated, refined, or disproved, but we hope that this process will contribute to the improvement of personalised treatment for patients with COPD exacerbations.

Moraxella catarrhalis induces an immune response in the murine lung that is independent of human CEACAM5 expression and long-term smoke exposure

In patients with chronic obstructive pulmonary disease (COPD), Moraxella catarrhalis infection of the lower airways is associated with chronic colonization and inflammation during stable disease and acute exacerbations. Chronic smoke exposure induces chronic inflammation and impairs mucociliary clearance, thus contributing to bacterial colonization of the lower airways in COPD patients. The human-specific carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 5, expressed in human airways, has been shown to contribute to epithelial colonization of CEACAM-binding pathogens. To investigate the impact of CEACAM5 expression on pulmonary M. catarrhalis colonization, we infected mice transgenic for human CEACAM5 (hCEACAM5) and wild type mice intratracheally with M. catarrhalis with or without preceding smoke exposure and analyzed bacterial colonization and local and systemic inflammation. Our results show that airway infection with M. catarrhalis accelerated acute local but not systemic inflammation, albeit independent of hCEACAM5 expression. Long-term smoke exposure alone or prior to M. catarrhalis infection did not contribute to increased local or systemic inflammation. No difference was found in pulmonary clearance of M. catarrhalis in hCEACAM5-transgenic mice compared with wild-type mice. Smoke exposure neither altered time nor extent of persistence of M. catarrhalis in the lungs of both genotypes. In conclusion, M. catarrhalis induced a local acute immune response in murine airways. Neither hCEACAM5 expression nor chronic smoke exposure nor a combination of both was sufficient as prerequisites for the establishment of chronic M. catarrhalis colonization. Our results demonstrate the difficulties in mirroring conditions of chronic airways colonization of M. catarrhalis in a murine model.

Functional Metagenomics of the Bronchial Microbiome in COPD

The course of chronic obstructive pulmonary disease (COPD) is frequently aggravated by exacerbations, and changes in the composition and activity of the microbiome may be implicated in their appearance. The aim of this study was to analyse the composition and the gene content of the microbial community in bronchial secretions of COPD patients in both stability and exacerbation. Taxonomic data were obtained by 16S rRNA gene amplification and pyrosequencing, and metabolic information through shotgun metagenomics, using the Metagenomics RAST server (MG-RAST), and the PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) programme, which predict metagenomes from 16S data. Eight severe COPD patients provided good quality sputum samples, and no significant differences in the relative abundance of any phyla and genera were found between stability and exacerbation. Bacterial biodiversity (Chao1 and Shannon indexes) did not show statistical differences and beta-diversity analysis (Bray-Curtis dissimilarity index) showed a similar microbial composition in the two clinical situations. Four functional categories showed statistically significant differences with MG-RAST at KEGG level 2: in exacerbation, Cell growth and Death and Transport and Catabolism decreased in abundance [1.6 (0.2-2.3) vs 3.6 (3.3-6.9), p = 0.012; and 1.8 (0-3.3) vs 3.6 (1.8-5.1), p = 0.025 respectively], while Cancer and Carbohydrate Metabolism increased [0.8 (0-1.5) vs 0 (0-0.5), p = 0.043; and 7 (6.4-9) vs 5.9 (6.3-6.1), p = 0.012 respectively]. In conclusion, the bronchial microbiome as a whole is not significantly modified when exacerbation symptoms appear in severe COPD patients, but its functional metabolic capabilities show significant changes in several pathways.

Biomarkers of progression of chronic obstructive pulmonary disease (COPD)

Disease progression of chronic obstructive pulmonary disease (COPD) is variable, with some patients having a relatively stable course, while others suffer relentless progression leading to severe breathlessness, frequent acute exacerbations of COPD (AECOPD), respiratory failure and death. Radiological markers such as CT emphysema index, bronchiectasis and coronary artery calcification (CAC) have been linked with increased mortality in COPD patients. Molecular changes in lung tissue reflect alterations in lung pathology that occur with disease progression; however, lung tissue is not routinely accessible. Cell counts (including neutrophils) and mediators in induced sputum have been associated with lung function and risk of exacerbations. Examples of peripheral blood biological markers (biomarkers) include those associated with lung function (reduced CC-16), emphysema severity (increased adiponectin, reduced sRAGE), exacerbations and mortality [increased CRP, fibrinogen, leukocyte count, IL-6, IL-8, and tumor necrosis factor α (TNF-α)] including increased YKL-40 with mortality. Emerging approaches to discovering markers of gene-environment interaction include exhaled breath analysis [volatile organic compounds (VOCs), exhaled breath condensate], cellular and systemic responses to exposure to air pollution, alterations in the lung microbiome, and biomarkers of lung ageing such as telomere length shortening and reduced levels of sirtuins. Overcoming methodological challenges in sampling and quality control will enable more robust yet easily accessible biomarkers to be developed and qualified, in order to optimise personalised medicine in patients with COPD.

Innate receptors and cellular defense against pulmonary infections

In the United States, lung infections consistently rank in the top 10 leading causes of death, accounting for >50,000 deaths annually. Moreover, >140,000 deaths occur annually as a result of chronic lung diseases, some of which may be complicated by an infectious process. The lung is constantly exposed to the environment and is susceptible to infectious complications caused by bacterial, viral, fungal, and parasitic pathogens. Indeed, we are continually faced with the threat of morbidity and mortality associated with annual influenza virus infections, new respiratory viruses (e.g., SARS-CoV), and lung infections caused by antibiotic-resistant "ESKAPE pathogens" (three of which target the lung). This review highlights innate immune receptors and cell types that function to protect against infectious challenges to the respiratory system yet also may be associated with exacerbations in chronic lung diseases.

Pharmacotherapy for lower respiratory tract infections

INTRODUCTION

Bacterial infections play an important role as etiological agents in acute exacerbations of chronic obstructive pulmonary disease (AECOPD), and exacerbations of non-cystic fibrosis (CF) bronchiectasis. In acute bronchitis and asthma exacerbations their role is less well defined than with patients with COPD. The clinical features, causative pathogens and therapies of common acute respiratory tract infections are detailed in this review.

AREAS COVERED

This article covers medical literature published in any language from 2000 to 2014, on 'lower respiratory tract infections', identified using PubMed, MEDLINE and ClinicalTrial.gov. The search terms used were 'COPD exacerbations', 'bronchiectasis', 'macrolides' and 'inhaled antibiotics'.

EXPERT OPINION

Given that almost half of AECOPD are caused by bacteria, administration of antibacterial agents is recommended for patients with severe exacerbations or severe underlying COPD. Chronic prophylactic use of macrolides seems to be of benefit, particularly in patients with bronchiectasis and chronic mucous hypersecretion. In an effort to manage chronic airway infection non-CF bronchiectasis due to drug-resistant pathogens, aerosolized antibiotics may be of value, and the data from recent studies are examined to demonstrate the potential value of this therapy, which is often used as an adjunctive measure to systemic antimicrobial therapy.

Healthy Eating Index 2005 and selected macronutrients are correlated with improved lung function in humans

A number of dietary components have been associated with lung function. However, a comprehensive measure of a healthy diet has not been compared with lung function. Herein, we test the hypothesis that a healthy overall diet, as assessed by the Healthy Eating Index 2005 (HEI-2005), will be associated with increased lung function. This is an investigation using the Atherosclerosis Risk in Communities Research Materials obtained from the National Heart Lung Blood Institute. The study surveyed dietary habits of 15 567 American subjects from 4 communities in 1987 to 1990. Spirometric measures of lung function were also taken at entry to the study and a second time 3 years later. Based on food and nutritional data collected by food frequency questionnaire, an HEI-2005 score was calculated for each subject. This total score, together with its 12 components scores and associated macronutrient, was compared with lung function results by linear regression. Models were controlled for smoking behavior, demographics, and other important covariates. The HEI-2005 total scores were positively associated with forced expiratory volume in 1 second per forced vital capacity (FEV(1)/FVC) at visit 1 (β = .101 per increase in 1 quintile of HEI-2005) and visit 2 (β = .140), and FEV(1) as percentage of the predicted FEV(1) at visit 2 (β = .215) (P < .05). In addition, HEI-2005 component scores that represented high intakes of whole grains (β = .127 and .096); saturated fats (β = -.091); and solid fats, alcohol, and added sugar (β = -.109 and -.131) were significantly associated with FEV(1)/FVC at either visit 1 or visit 2. Intakes of total calories (β =-.082 at visit 1) and saturated fatty acids (β = -.085 at visit 2) were negatively associated with FEV(1)/FVC. Dietary polyunsaturated fatty acids (β = .085 and .116) and long-chain omega-3 fatty acids (β = .109 and .103), animal protein (β = .132 and .093), and dietary fiber (β = .129) were positively associated with lung health. An overall healthy diet is associated with higher lung function.