Microbiologic determinants of exacerbation in chronic obstructive pulmonary disease

Comprehensive characterisation of pulmonary and serum surfactant protein D in COPD

Background

Pulmonary surfactant protein D (SP-D) is considered as a candidate biomarker for the functional integrity of the lung and for disease progression, which can be detected in serum. The origin of SP-D in serum and how serum concentrations are related to pulmonary concentrations under inflammatory conditions is still unclear.

Methods

In a cross-sectional study comprising non-smokers (n = 10), young - (n = 10), elderly smokers (n = 20), and smokers with COPD (n = 20) we simultaneously analysed pulmonary and serum SP-D levels with regard to pulmonary function, exercise, repeatability and its quaternary structure by native gel electrophoresis. Statistical comparisons were conducted by ANOVA and post-hoc testing for multiple comparisons; repeatability was assessed by Bland-Altman analysis.

Results

In COPD, median (IQR) pulmonary SP-D levels were lower (129(68) ng/ml) compared to smokers (young: 299(190), elderly: 296(158) ng/ml; p < 0.01) and non-smokers (967(708) ng/ml; p < 0.001). The opposite was observed in serum, with higher concentrations in COPD (140(89) ng/ml) as compared to non-smokers (76(47) ng/ml; p < 0.01). SP-D levels were reproducible and correlated with the degree of airway obstruction in all smokers. In addition, smoking lead to disruption of the quaternary structure.

Conclusions

Pulmonary and serum SP-D levels are stable markers influenced by smoking and related to airflow obstruction and disease state. Smaller subunits of pulmonary SP-D and the rapid increase of serum SP-D levels in COPD due to exercise support the translocation hypothesis and its use as a COPD biomarker.

Trial registration

no interventional trial

Differential adaptation of microbial pathogens to airways of patients with cystic fibrosis and chronic obstructive pulmonary disease

Cystic fibrosis (CF), the most common autosomal recessive disorder in Caucasians, and chronic obstructive pulmonary disease (COPD), a disease of adults, are characterized by chronic lung inflammation, airflow obstruction and extensive tissue remodelling, which have a major impact on patients' morbidity and mortality. Airway inflammation is stimulated in CF by chronic bacterial infections and in COPD by environmental stimuli, particularly from smoking. Pseudomonas aeruginosa is the major bacterial pathogen in CF, while in COPD, Haemophilus influenzae is most frequently observed. Molecular studies indicate that during chronic pulmonary infection, P. aeruginosa clones genotypically and phenotypically adapt to the CF niche, resulting in a highly diverse bacterial community that is difficult to eradicate therapeutically. Pseudomonas aeruginosa clones from COPD patients remain within the airways only for limited time periods, do not adapt and are easily eradicated. However, in a subgroup of severely ill COPD patients, P. aeruginosa clones similar to those in CF persist. In this review, we will discuss the pathophysiology of lung disease in CF and COPD, the complex genotypic and phenotypic adaptation processes of the opportunistic bacterial pathogens and novel treatment options.

The benefits of long-term systemic antimicrobial therapy in chronic obstructive pulmonary disease

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are major contributors to the morbidity and mortality associated with this disease. Current approaches that likely reduce chronic obstructive pulmonary disease (COPD) exacerbations include smoking cessation, influenza and pneumococcal vaccinations, long-acting bronchodilator and inhaled corticosteroid therapy, pulmonary rehabilitation, and mucolytic drugs. However, with optimal treatment using all of these modalities, we are only able to reduce exacerbations by about 40%. A significant proportion of COPD exacerbations are bacterial, therefore long-term antimicrobial therapy could have a role in preventing exacerbations. Long-term antibiotic treatment in COPD regimens that are being evaluated include low-dose macrolide therapy, pulsed fluoroquinolone administration and the use of inhaled antibiotics. Although initial results have been promising with significant reductions in exacerbations with these regimens, additional studies are required to identify the appropriate patient and regimen and elucidate the risk-benefit as well as cost effectiveness of long-term antibiotics in COPD.

Cough and sputum production as risk factors for poor outcomes in patients with COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality in developed countries, and its prevalence is projected to increase over the coming decades. According to the World Health Organization, COPD will become the third leading cause of death worldwide by 2020. COPD has a chronic and progressive course, and is often aggravated by exacerbations, which typically arise as a result of bronchial infection. Exacerbations are characterised by periods of increasing acute symptoms, particularly cough, dyspnoea and production of sputum, which worsen airflow obstruction, further impair quality of life and generally require a change in regular medication. Exacerbations are the most common cause of medical visits, hospital admissions and death in patients with COPD, and frequent exacerbations worsen health status and may cause a permanent decline in lung function. Chronic cough and sputum production are common in the general population, but significantly more prevalent in patients with respiratory disorders; these symptoms have been suggested as a risk factor for exacerbations of COPD. This article will review the consequences of chronic cough and sputum production in patients with COPD and analyse whether these risk factors may be useful for identifying a specific phenotype of patient that requires different management to reduce the occurrence of exacerbations.

Chronic obstructive pulmonary disease: role of bacteria and updated guide to antibacterial selection in the older patient

Chronic obstructive pulmonary disease (COPD) remains a major cause of morbidity and mortality worldwide. COPD is especially prevalent in the elderly, affecting 25% of those aged>or=75 years. The course of the disease in the elderly is often complicated by co-morbid conditions, and its management is complicated by drug-drug interactions. Exacerbations of COPD increase rates of hospitalization and mortality and decrease quality of life. Exacerbations are marked by an increase from baseline in dyspnoea, sputum volume and sputum purulence. Approximately 50% of acute exacerbations of symptoms in COPD are caused by non-typeable Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae and Pseudomonas aeruginosa. Stratification of exacerbations based on severity of symptoms and signs, and severity of underlying COPD, is useful in selecting patients likely to benefit from antibacterial therapy. Patients who are hospitalized with exacerbations, those who have all three symptoms (increased dyspnoea, sputum volume and sputum purulence), and those with severe underlying COPD and exacerbations benefit most from antibacterials. Antibacterial susceptibility patterns among the bacterial pathogens are evolving, and knowledge of local susceptibility patterns is useful in antibacterial selection. Penicillin, amoxicillin, cotrimoxazole (trimethoprim/sulfamethoxazole) and doxycycline should not be used as an initial antibacterial because of resistance patterns. We recommend second-/third-generation cephalosporins, amoxicillin/clavulanic acid, azithromycin and respiratory fluoroquinolones as initial choices. In patients at risk of colonization by, and infection as a result of, P. aeruginosa, ciprofloxacin, levofloxacin or an advanced penicillin/penicillinase combination effective against this species should be used. Drug-drug interactions should be considered in antibacterial choice. The goals of antibacterial therapy for exacerbations of COPD are the prevention of complications such as respiratory failure and death, and the reduction of treatment failures. The role of pathogenic bacteria in progression of stable COPD and the use of prophylactic antibacterials in stable COPD are under investigation. Currently available evidence does not support routine clinical use of prophylactic antibacterials in stable COPD. In conclusion, pathogenic bacteria cause a significant proportion of acute exacerbations of COPD. Use of antibacterials, based on current susceptibility patterns, is beneficial in patients with severe COPD experiencing exacerbations and in patients with severe exacerbations.

Budesonide enhances Toll-like receptor 2 expression in activated bronchial epithelial cells

Endotoxin, tumor necrosis factor (TNF), and organic dust constitute proinflammatory stimuli involved in the initiation of inflammation. The major receptor for endotoxin (lipopolysaccharide [LPS]) is Toll-like receptor 4 (TLR4), whereas TLR2 binds to agents from gram-positive bacteria. The aim of the study was to elucidate whether TLR2 and TLR4, expressed on primary bronchial epithelial cells (PBECs), are influenced by exogenous (organic dust and LPS) and endogenous (TNF) stimuli and whether this interaction is influenced by a glucocorticosteroid. The cells were exposed to LPS (10 microg/ml), TNF (10 ng/ml), or dust (100 microg/ml) 1.5 and 6 h, in the presence or absence of budesonide (10(-6) M) in vitro. The mRNA expression of interleukin (IL)-6, IL-8, TLR2, and TLR4 were measured with real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and IL-6 and IL-8 release was assessed with enzyme-linked immunosorbent assay (ELISA). To elucidate the importance of TLR-signaling for IL-6 and IL-8 secretion, the effect of TLR-blockers was studied. Endotoxin, TNF, and dust stimulated the release of IL-6 and IL-8 in a time-dependent manner. Budesonide significantly attenuated the release and expression of IL-6 and IL-8 after exposure. Budesonide did not influence TLR expression, but costimulation with LPS, TNF, or dust together with budesonide increased TLR2 expression synergistically. Blocking of TLR2 and TLR4 reduced cytokine secretion in stimulated cells. Budesonide reduced IL-6 and IL-8 production and enhanced expression of TLR2 in PBECs only in the presence of a proinflammatory stimulus. These findings contribute to our understanding of the beneficial effects of glucocorticosteroids during chronic obstructive pulmonary disease (COPD) exacerbations and asthma, which are frequently caused by microorganisms.

Azithromycin inhibits nontypeable Haemophilus influenzae-induced MUC5AC expression and secretion via inhibition of activator protein-1 in human airway epithelial cells

Nontypeable Haemophilus influenzae (NTHi) is one of the most common pathogens in chronic airway infections and exacerbation. The hallmark of chronic respiratory diseases, including cystic fibrosis, diffuse panbronchiolitis and chronic obstructive pulmonary disease, is mucin overproduction. Prolonged macrolide antibiotic therapy at low doses is known to improve clinical outcome in patients with chronic respiratory diseases via anti-inflammatory effects. In this study, we investigated the effects of macrolide therapy on NTHi-induction of the MUC5AC mucin in human airway epithelial cells. A 15-membered macrolide, azithromycin, but not a 14-membered macrolide, clarithromycin, inhibited NTHi-induction of MUC5AC at both the mRNA and protein levels through selective suppression of activation of the transcription factor activator protein-1. Our findings suggest that each macrolide affects MUC5AC production in different ways and that azithromycin is more suitable for the treatment of NTHi-induced respiratory infection.

Pseudomonas aeruginosa and the host pulmonary immune response

Pseudomonas aeruginosa is a highly adaptable, opportunistic pathogen that is commonly found in the environment. It can infect a number of sites in the body and disseminate. It can cause both acute and chronic pulmonary infection and the acuity of infection and accompanying inflammatory phenotype is determined, for the most part, by the host. Although P. aeruginosa has been a successful opportunist in the context of a number of different disease states, it has been best studied in the context of cystic fibrosis (CF). The adaptability of P. aeruginosa has enabled it to adjust quickly to the CF airway, transitioning from initial colonization to chronic infection. The organism quickly expresses virulence factors that allow it to circumvent some elements of the host immune response and, even more importantly, quickly develops antimicrobial resistance. In the case of CF, chronic infection resulting in progressive lung damage, coupled with antimicrobial resistance, becomes an increasingly important issue as individuals with CF live longer. It is for these reasons that both organism- and host-targeted immunotherapies are being increasingly explored.

Antibiotics in acute exacerbations of chronic bronchitis

Acute exacerbations of chronic bronchitis (AECB) are a major contributor to morbidity and mortality in patients with chronic obstructive pulmonary disease, accounting for more than 16 million physician office visits and over 500,000 hospitalizations in the USA each year. Antimicrobials have been recognized by clinical guidelines as an important component in the management of AECB with a bacterial etiology. The challenge of identifying patients most likely to benefit from antimicrobial therapy is difficult in the clinical setting. However, appropriate risk stratification of patients, and the use of antimicrobials within the correct spectrum and for a suitable duration, can improve clinical outcomes while minimizing induction of antimicrobial resistance. With an improved design in pharmacologic and clinical studies, differences can be appreciated among the various antimicrobial agents available to treat AECB. Factors to be considered in antimicrobial agent selection include local tissue penetration, effects on bacteriological eradication, duration of therapy, speed of resolution and prevention or delay of recurrences.

A persistent and diverse airway microbiota present during chronic obstructive pulmonary disease exacerbations

Acute exacerbations of chronic obstructive pulmonary disease (COPD) are a major source of morbidity and contribute significantly to healthcare costs. Although bacterial infections are implicated in nearly 50% of exacerbations, only a handful of pathogens have been consistently identified in COPD airways, primarily by culture-based methods, and the bacterial microbiota in acute exacerbations remains largely uncharacterized. The aim of this study was to comprehensively profile airway bacterial communities using a culture-independent microarray, the 16S rRNA PhyloChip, of a cohort of COPD patients requiring ventilatory support and antibiotic therapy for exacerbation-related respiratory failure. PhyloChip analysis revealed the presence of over 1,200 bacterial taxa representing 140 distinct families, many previously undetected in airway diseases; bacterial community composition was strongly influenced by the duration of intubation. A core community of 75 taxa was detected in all patients, many of which are known pathogens. Bacterial community diversity in COPD airways is substantially greater than previously recognized and includes a number of potential pathogens detected in the setting of antibiotic exposure. Comprehensive assessment of the COPD airway microbiota using high-throughput, culture-independent methods may prove key to understanding the relationships between airway bacterial colonization, acute exacerbation, and clinical outcomes in this and other chronic inflammatory airway diseases.

Mixed community-acquired lower respiratory tract infections

Although mixed infections are known to be clinically relevant in conditions such as nosocomial pneumonia and ventilator-related pneumonia, it is increasingly recognized that a substantial number of community-acquired lower respiratory tract infections may also be attributed to more than one pathogenic organism. A better definition of the true incidence of mixed infections in community-acquired lower respiratory tract infections is partly derived from recent advances in available diagnostic methods (eg, molecular biology). Two points still must be determined: whether the presence of a mixed infection is associated with altered outcomes and whether empirical antibiotic selection should be modified to account for potential polymicrobial infections.

Colour of sputum is a marker for bacterial colonisation in chronic obstructive pulmonary disease

BACKGROUND

Bacterial colonisation in chronic obstructive pulmonary disease (COPD) contributes to airway inflammation and modulates exacerbations. We assessed risk factors for bacterial colonisation in COPD.

METHODS

Patients with stable COPD consecutively recruited over 1 year gave consent to provide a sputum sample for microbiologic analysis. Bronchial colonisation by potentially pathogenic microorganisms (PPMs) was defined as the isolation of PPMs at concentrations of > or =102 colony-forming units (CFU)/mL on quantitative bacterial culture. Colonised patients were divided into high (>105 CFU/mL) or low (<105 CFU/mL) bacterial load.

RESULTS

A total of 119 patients (92.5% men, mean age 68 years, mean forced expiratory volume in one second [FEV1] [% predicted] 46.4%) were evaluated. Bacterial colonisation was demonstrated in 58 (48.7%) patients. Patients with and without bacterial colonisation showed significant differences in smoking history, cough, dyspnoea, COPD exacerbations and hospitalisations in the previous year, and sputum colour. Thirty-six patients (62% of those colonised) had a high bacterial load. More than 80% of the sputum samples with a dark yellow or greenish colour yielded PPMs in culture. In contrast, only 5.9% of white and 44.7% of light yellow sputum samples were positive (P < 0.001). Multivariate analysis showed an increased degree of dyspnoea (odds ratio [OR] = 2.63, 95% confidence interval [CI] 1.53-5.09, P = 0.004) and a darker sputum colour (OR = 4.11, 95% CI 2.30-7.29, P < 0.001) as factors associated with the presence of PPMs in sputum.

CONCLUSIONS

Almost half of our population of ambulatory moderate to very severe COPD patients were colonised with PPMs. Patients colonised present more severe dyspnoea, and a darker colour of sputum allows identification of individuals more likely to be colonised.

Comparative effectiveness of macrolides and quinolones for patients hospitalized with acute exacerbations of chronic obstructive pulmonary disease (AECOPD)

BACKGROUND

Meta-analyses of randomized trials have found that antibiotics are effective in acute exacerbations of chronic obstructive pulmonary disease (AECOPD), but there is insufficient evidence to guide antibiotic selection. Current guidelines offer conflicting recommendations.

OBJECTIVE

To compare the effectiveness of macrolides and quinolones for AECOPD DESIGN: Retrospective cohort study using logistic regression, propensity score-matching, and grouped treatment models.

SETTING

A total of 375 acute care hospitals throughout the United States.

PATIENTS

Age > or =40 years and hospitalized for AECOPD.

INTERVENTION

Macrolide or quinolone antibiotic begun in the first 2 hospital days.

MEASUREMENTS

Treatment failure (defined as the initiation of mechanical ventilation after hospital day 2, inpatient mortality, or readmission for AECOPD within 30 days), length of stay, and hospital costs.

RESULTS

Of the 19,608 patients who met the inclusion criteria, 6139 (31%) were treated initially with a macrolide and 13,469 (69%) with a quinolone. Compared to patients treated initially with a quinolone, those who received macrolides had a lower risk of treatment failure (6.8% vs. 8.1%; P < 0.01), a finding that was attenuated after multivariable adjustment (odds ratio [OR], 0.89; 95% confidence interval [CI], 0.78-1.01), and disappeared in a grouped-treatment analysis (OR, 1.01; 95% CI, 0.75-1.35). There were no differences in adjusted length of stay (ratio, 0.98; 95% CI, 0.97-1.00) or adjusted cost (ratio, 1.00; 95% CI, 0.99-1.02). After propensity score-matching, antibiotic-associated diarrhea was more common with quinolones (1.2% vs. 0.6%; P < 0.001).

CONCLUSIONS

Macrolide and quinolone antibiotics are associated with similar rates of treatment failure in AECOPD; however, macrolides are less frequently associated with diarrhea.

Upper-respiratory viral infection, biomarkers, and COPD exacerbations

Background

Respiratory viruses frequently are recovered in the upper-respiratory tract during acute exacerbations of COPD (AECOPD), but their role as contributing pathogens remains unclear. The usefulness of procalcitonin and C-reactive protein as indicators of the presence or absence of viral infection in this setting also needs to be evaluated.

Methods

The study was of a prospective cohort of patients with COPD admitted to the ED for AECOPD. Reverse transcriptase-polymerase chain reaction (RT-PCR) for 14 respiratory viruses was performed on nasopharyngeal swabs collected at admission and after recovery in stable condition.

Results

Eighty-six patients (mean age, 72 years; male, 64%) were included. During AECOPD, upper-respiratory viral infections were detected in 44 (51%) patients: picornavirus in 22, metapneumovirus in seven, coronavirus in eight, influenza A/B in two, parainfluenza in two, and respiratory syncytial virus in three. A dual infection was present in three patients. After recovery, viruses were detected in only eight (11%) of 71 patients (P < .001 compared with AECOPD phase). In five of these patients, no virus had been identified during the initial exacerbation, thus suggesting a new viral infection acquired during follow-up. During AECOPD, procalcitonin and C-reactive protein levels did not differ significantly between patients with or without a proven viral infection.

Conclusions

Prevalence of upper-respiratory viral infection, as detected from nasopharyngeal swab by RT-PCR, is high in AECOPD and low after clinical recovery, suggesting that AECOPD frequently are triggered by viral infections initiated in the upper-respiratory tract. In our study, serum procalcitonin and C-reactive protein did not discriminate virus-associated exacerbations from others.

Trial registration

clinicaltrials.gov; Identifier: NCT00448604.

COPD and the response of the lung to tobacco smoke exposure

Chronic Obstructive Pulmonary Disease (COPD) is a major cause of death in the western world and increasing in prevalence in developing countries. COPD is characterised by irreversible airflow obstruction, loss of lung tissue, reduced quality of life and high rates of mortality. The major cause of COPD is tobacco smoke. The changes in the innate immune system directed by tobacco smoke exposure lead to a pronounced and chronic inflammation in the lung. This in turn leads to other pathological changes including remodelling and destruction of lung tissue. Tobacco smoke exposure also leads to infection of the lung by bacteria and viruses. These, bacteria, viruses and co-infection are key triggers of acute worsening's of COPD termed exacerbations. COPD exacerbations are an additional major factor in the morbidity and mortality within COPD and are also the major healthcare costs associated with the disease. Within this review we discuss the response of the immune system to cigarette smoke exposure and inappropriate harmful responses. Successful treatment strategies will need to balance the positive effects of reducing inflammatory aspects of the disease whilst retaining some of the needed immune responses triggered by tobacco smoke exposure.

Binding of complement regulators to invasive nontypeable Haemophilus influenzae isolates is not increased compared to nasopharyngeal isolates, but serum resistance is linked to disease severity

The aim of the present study was to analyze the importance of nontypeable Haemophilus influenzae (NTHi) isolated from patients with sepsis (invasive isolates) compared to nasopharyngeal isolates from patients with upper respiratory tract infection for resistance to complement-mediated attack in human serum and to correlate this result with disease severity. We studied and characterized cases of invasive NTHi disease in detail. All patients with invasive NTHi isolates were adults, and 35% had a clinical presentation of severe sepsis according to the ACCP/SCCM classification of sepsis grading. Moreover, 41% of the patients had evidence of immune deficiency. The different isolates were analyzed for survival in human serum and for binding of 125I-labeled, purified human complement inhibitors C4b-binding protein (C4BP), factor H, and vitronectin, in addition to binding of regulators directly from serum. No significant differences were found when blood-derived and nasopharyngeal isolates were compared, suggesting that interactions with the complement system are equally important for NTHi strains, irrespective of isolation site. Interestingly, a correlation between serum resistance and invasive disease severity was found. The ability to resist the attack of the complement system seems to be important for NTHi strains infecting the respiratory tract as well as the bloodstream.

Bibliography. Current world literature

This bibliography is compiled by clinicians from the journals listed at the end of this publication. It is based on literature entered into our database between 1 November 2007 and 31 October 2008 (articles are generally added to the database about two and a half months after publication). In addition, the bibliography contains every paper annotated by reviewers; these references were obtained from a variety of bibliographic databases and published between the beginning of the review period and the time of going to press. The bibliography has been grouped into topics that relate to the reviews in this issue.

Pseudomonas aeruginosa in adults with chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Pseudomonas aeruginosa is isolated in sputum cultures from adults with chronic obstructive pulmonary disease (COPD) but the significance of the organism in this clinical setting is not well known. The purpose of this review is to critically review the literature in an effort to understand the role of P. aeruginosa in the course and pathogenesis of COPD.

RECENT FINDINGS

When examined longitudinally, two distinct patterns of carriage of P. aeruginosa are observed in adults with COPD: short-term colonization followed by clearance and long-term persistence. Acquisition of P. aeruginosa is associated with the occurrence of an exacerbation, indicating that the organism causes exacerbations. Exacerbations caused by P. aeruginosa are more likely to be seen in patients with more advanced COPD, those who have received recent antibiotic therapy and those who require mechanical ventilation for an exacerbation. A subset of adults with COPD becomes chronically colonized with P. aeruginosa, but whether such patients benefit from antimicrobial therapy is not yet known.

SUMMARY

P. aeruginosa has several different manifestations in the setting of COPD. The organism is a colonizer that is cleared quickly, causes acute exacerbations and also may cause chronic infection in a subset of adults with COPD.

Budesonide and the risk of pneumonia: a meta-analysis of individual patient data

BACKGROUND

Concern is continuing about increased risk of pneumonia in patients with chronic obstructive pulmonary disease (COPD) who use inhaled corticosteroids. We aimed to establish the effects of inhaled budesonide on the risk of pneumonia in such patients.

METHODS

We pooled patient data from seven large clinical trials of inhaled budesonide (320-1280 mug/day), with or without formoterol, versus control regimen (placebo or formoterol alone) in patients with stable COPD and at least 6 months of follow-up. The primary analysis compared treatment groups for the risk of pneumonia as an adverse event or serious adverse event during the trial or within 15 days of the trial end. Cox proportional hazards regression was used to analyse the data on an intention-to-treat basis. Data were adjusted for patients' age, sex, smoking status, body-mass index, and postbronchodilator percent of predicted forced expiratory volume in 1 s (FEV(1)).

FINDINGS

We analysed data from 7042 patients, of whom 3801 were on inhaled budesonide and 3241 were on control treatment, with 5212 patient-years of exposure to treatment. We recorded no significant difference between treatment groups for the occurrence of pneumonia as an adverse event (3% [n=122 patients] vs 3% [n=103]; adjusted hazard ratio 1.05, 95% CI 0.81-1.37) or a serious adverse event (1% [n=53] vs 2% [n=50]; 0.92, 0.62-1.35), or for time to pneumonia as an adverse event (log-rank test 0.94) or a serious adverse event (0.61). Increasing age and decreasing percent of predicted FEV(1) were the only two variables that were significantly associated with occurrence of pneumonia as an adverse event or a serious adverse event.

INTERPRETATION

Budesonide treatment for 12 months does not increase the risk of pneumonia in patients with COPD during that time and therefore is safe for clinical use in such patients.

FUNDING

Michael Smith Foundation for Health Research.

Nontypeable Haemophilus influenzae protein E binds vitronectin and is important for serum resistance

Nontypeable Haemophilus influenzae (NTHi) commonly causes local disease in the upper and lower respiratory tract and has recently been shown to interfere with both the classical and alternative pathways of complement activation. The terminal pathway of the complement system is regulated by vitronectin that is a component of both plasma and the extracellular matrix. In this study, we identify protein E (PE; 16 kDa), which is a recently characterized ubiquitous outer membrane protein, as a vitronectin-binding protein of NTHi. A PE-deficient NTHi mutant had a markedly reduced survival in serum compared with the PE-expressing isogenic NTHi wild type. Moreover, the PE-deficient mutant showed a significantly decreased binding to both soluble and immobilized vitronectin. In parallel, PE-expressing Escherichia coli bound soluble vitronectin and adhered to immobilized vitronectin compared with controls. Surface plasmon resonance technology revealed a K(D) of 0.4 microM for the interaction between recombinant PE and immobilized vitronectin. Moreover, the PE-dependent vitronectin-binding site was located at the heparin-binding domains of vitronectin and the major vitronectin-binding domain was found in the central core of PE (aa 84-108). Importantly, vitronectin bound to the surface of NTHi 3655 reduced membrane attack complex-induced hemolysis. In contrast to incubation with normal human serum, NTHi 3655 showed a reduced survival in vitronectin-depleted human serum, thus demonstrating that vitronectin mediates a protective role at the bacterial surface. Our findings show that PE, by binding vitronectin, may play an important role in NTHi pathogenesis.

Pathogenesis of Bacterial Exacerbations of COPD

Acute exacerbations are significant events in the course of COPD. The pathogenesis of exacerbations was poorly understood, specifically, the role of bacteria was highly controversial. Recent observations have demonstrated that bacterial infection is involved in about half of the exacerbations. The predominant mechanism of bacterial exacerbation in COPD appears to be acquisition of new strains of bacterial pathogens from the environment that are able to establish infection in the tracheobronchial tree in COPD because of compromised innate lung defenses. These pathogens interact with airway cells, elicit an inflammatory response, which underlies the pathophysiology and symptoms characteristic of exacerbation. An immune response that can be mucosal, systemic or both develops to the infecting bacterial strain. This immune response contains the infectious process, could eradicate the infecting pathogen and prevent re-infection with the same strain. However, because of antigenic diversity among bacterial strains, this immunity tends to be strain-specific rather than widely protective. Other mechanisms, including increase in bacterial load and interaction with other etiologies such as viruses, also could contribute to bacterial exacerbations. Improved understanding of the host-pathogen interaction in the airways in COPD will lead to novel approaches to prevention and treatment of exacerbations.

Systemic humoral immunity to non-typeable Haemophilus influenzae

Non-typeable Haemophilus influenzae (NTHi) is a major cause of respiratory but rarely systemic infection. The host defence to this bacterium has not been well defined in patients with chronic airway infection. The aim of this study was to assess the effect of humoral immunity in host defence to NTHi. Responses were measured in control and bronchiectasis subjects who had recurrent bronchial infection. Antibody and complement-mediated killing was assessed by incubating NTHi with serum and the role of the membrane-attack complex and classical/alternate pathways of complement activation measured. The effect of one strain to induce protective immunity against other strains was assessed. The effect of antibody on granulocyte intracellular killing of NTHi was also measured. The results showed that both healthy control subjects and bronchiectasis patients all had detectable antibody to NTHi of similar titre. Both groups demonstrated effective antibody/complement-mediated killing of different strains of NTHi. This killing was mediated through the membrane-attack complex and the classical pathway of complement activation. Immunization of rabbits with one strain of NTHi resulted in protection from other strains in vitro. Antibody activated granulocytes to kill intracellular bacteria. These findings may explain why NTHi rarely causes systemic disease in patients with chronic respiratory mucosal infection and emphasize the potential importance of cellular immunity against this bacterium.

Bacteriology in acute exacerbation of chronic obstructive pulmonary disease in patients admitted to hospital

We investigated the bacterial flora and antimicrobial sensitivity in sputum from patients admitted to hospital with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in order to recommend the best empirical treatment for these patients. The survey was a retrospective study of all patients admitted to Hvidovre hospital with the diagnosis AECOPD during 2004. A total of 118 patients were included. Microscopy, culture and sensitivity testing investigated their sputums. Clinical and paraclinical features were collected from the patients' files. Among the 118 patients, 59 (50%) had a positive sputum culture. The group with positive cultures had a higher blood neutrophil count (p=0.03). There were no other clinical differences between the groups with and without positive sputum culture. The majority of patients with positive sputum cultures were infected with bacteria other than S. pneumonia, mostly H. influenzae and Moraxella catarrhalis. Patients with low FEV(1)<1.0 litre were more likely to be infected with Pseudomonas aeruginosa (p=0.03). The sensitivity patterns of the bacteria showed that the majority were resistant to penicillin. If antibiotics are initiated empirically for AECOPD we recommend either cefuroxime for intravenous treatment or amoxicillin-clavulanate for oral treatment.

Mortality of COPD patients infected with multi-resistant Pseudomonas aeruginosa: a case and control study

BACKGROUND

The incidence of infections caused by multiresistant Pseudomonas aeruginosa (MDRP) is increasing, especially in critically ill patients. The relevance of MDRP in the prognosis of chronic obstructive pulmonary disease (COPD) acute exacerbation in patients admitted to the hospital's general ward is not well known.

PATIENTS AND METHODS

Case and control study. Cases were patients admitted for COPD acute exacerbation in which a MDRP was isolated from spontaneous sputum. MDRP was defined as the absence of susceptibility to three or more antibiotic families (betalactams, quinolones, carbapenems and aminoglycosides). Patients currently or previously admitted to the intensive care unit (ICU), who had a recent surgery, neoplasia or immunosuppressive treatment were excluded from the study. Patients from the control group were admitted for COPD acute exacerbation and matched 1:1 with each case-patient in terms of age, sex, date of admission and degree of airway obstruction. Pseudomonas aeruginosa susceptible to all antimicrobials or other microorganisms was isolated from sputum.

RESULTS

During the study period (2000-2005), 50 case-patients and 50 controls were included. Crude mortality at 2 years was 60% for the case-patients and 28% for the control group. In the logistic regression analysis adjusted for age, FEV(1) and number of previous hospital admissions, MDRP infection was associated to an increased mortality in comparison to patients without MDRP (OR = 6.2; IC 95%: 1.7-22.1; p < 0.01).

CONCLUSIONS

In COPD patients admitted to the general ward, acute exacerbation with MDRP in sputum was associated with higher mortality.

Procalcitonin levels in acute exacerbation of COPD admitted in ICU: a prospective cohort study

BACKGROUND

Antibiotics are recommended for severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD) admitted to intensive care units (ICU). Serum procalcitonin (PCT) could be a useful tool for selecting patients with a lower probability of developing bacterial infection, but its measurement has not been investigated in this population.

METHODS

We conducted a single center prospective cohort study in consecutive COPD patients admitted to the ICU for AECOPD between September 2005 and September 2006. Sputum samples or tracheal aspirates were tested for the presence of bacteria and viruses. PCT levels were measured at the time of admittance, six hours, and 24 hours using a sensitive immunoassay.

RESULTS

Thirty nine AECOPD patients were included, 31 of which (79%) required a ventilator support at admission. The median [25%-75% interquartile range] PCT level, assessed in 35/39 patients, was: 0.096 microg/L [IQR, 0.065 to 0.178] at the time of admission, 0.113 microg/L [IQR, 0.074 to 0.548] at six hours, and 0.137 microg/L [IQR, 0.088 to 0.252] at 24 hours. The highest PCT (PCTmax) levels were less than 0.1 microg/L in 14/35 (40%) patients and more than 0.25 microg/L in 10/35 (29%) patients, suggesting low and high probability of bacterial infection, respectively. Five species of bacteria and nine species of viruses were detected in 12/39 (31%) patients. Among the four patients positive for Pseudomonas aeruginosa, one had a PCTmax less than 0.25 microg/L and three had a PCTmax less than 0.1 microg/L. The one patient positive for Haemophilus influenzae had a PCTmax more than 0.25 microg/L. The presence or absence of viruses did not influence PCT at time of admission (0.068 vs 0.098 microg/L respectively, P = 0.80).

CONCLUSION

The likelihood of bacterial infection is low among COPD patients admitted to ICU for AECOPD (40% with PCT < 0.1 microg/L) suggesting a possible inappropriate use of antibiotics. Further studies are necessary to assess the impact of a procalcitonin-based therapeutic strategy in critically ill COPD patients.

Cytotoxic T lymphocyte and natural killer cell responses to non-typeable Haemophilus influenzae

Cytotoxic T lymphocytes (CTL) and natural killer (NK) cells have a key role in host defence against infectious pathogens, but their response to bacteria is not well characterized. Non-typeable Haemophilus influenzae is a major cause of respiratory tract infection including otitis media, sinusitis, tonsillitis and chronic bronchitis (especially in chronic obstructive pulmonary disease and bronchiectasis). This bacterium is also present in the pharynx of most healthy adults. The primary factor that may determine whether clinical disease occurs or not is the nature of the lymphocyte response. Here we examined the CTL cell and NK cell responses to nontypeable H. influenzae in healthy control subjects and in subjects who had bronchiectasis and recurrent bronchial infection with this bacterium. Cells were stimulated with live H. influenzae and intracellular cytokine production and release of cytotoxic granules measured. Control subjects had significantly higher levels of interferon gamma production by both CTL and NK cells, while levels of cytotoxic granule release were similar in both groups. The main lymphocyte subsets that proliferated in response to H. influenzae stimulation were the CTL and NK cells. The results suggest that CTL and NK cell responses may be important in preventing disease from nontypeable H. influenzae infection.

Review: Surfactant protein D: A lung specific biomarker in COPD?

A major impediment in the development of novel drugs for chronic obstructive pulmonary disease (COPD) has been the scarcity of a well-validated, robust, and easily obtainable intermediate end point such as serum biomarkers. To date the best serum biomarkers in COPD have been non-speci“c pro-in”ammatory molecules synthesized largely by extra-pulmonary organs. In COPD, an ideal biomarker would be one that (1) was produced mostly in the lungs (and was reliably measurable in the peripheral circulation using commercially available kits), (2) changed with the clinical status of patients or with relevant exposures; and (3) had inherent functional attributes that suggested a possible causal role in the pathogenesis of the disease. In this paper, we review one promising systemic biomarker that ful“lls some of these criteria, surfactant protein D (SPD).

Pseudomonas aeruginosa in chronic obstructive pulmonary disease

RATIONALE

Pseudomonas aeruginosa is isolated from adults with chronic obstructive pulmonary disease (COPD) in cross-sectional studies. However, patterns of carriage and the role of P. aeruginosa in COPD are unknown.

OBJECTIVES

To elucidate carriage patterns, phenotypes of strains, clinical manifestations, and the antibody response to P. aeruginosa in COPD.

METHODS

A prospective study of adults with COPD was conducted. Isolates of P. aeruginosa were subjected to genotypic and phenotypic analysis. Sputum samples were studied for P. aeruginosa DNA, and immune responses were assayed.

MEASUREMENTS AND MAIN RESULTS

We analyzed longitudinal clinical data, sputum cultures, pulsed-field gel electrophoresis of bacterial DNA, polymerase chain reaction of sputum, and immunoblot assays of serum. Fifty-seven episodes of acquisition of strains of P. aeruginosa were observed in 39 of 126 patients over 10 years. Acquisition of a new strain was associated with exacerbation. Thirty-one episodes of carriage were followed by clearance of the strain; 16 were of short (<1 mo) duration. Thirteen strains demonstrated persistence, and 13 strains were of indeterminate duration. Six strains were mucoid and were more likely to persist than nonmucoid strains (P = 0.005). Antibody responses developed in 53.8% of persistent carriage and in only 9.7% of short-term carriage episodes (P = 0.003). Antibiotics did not account for clearance.

CONCLUSIONS

Two distinct patterns of carriage by P. aeruginosa were observed: (1) short-term colonization followed by clearance and (2) long-term persistence. Mucoid strains showed persistence. Acquisition of P. aeruginosa is associated with the occurrence of an exacerbation. Serum antibody responses do not mediate clearance of P. aeruginosa.

Infections in chronic lung diseases

Chronic lung diseases are prevalent worldwide and cause significant mortality and suffering. This article discusses infections that occur in three chronic lung diseases: chronic obstructive pulmonary disease, bronchiectasis, and cystic fibrosis. Rather than discussing the role of infections as etiology of these diseases, this article focuses on infections that occur in the background of established chronic lung disease.

Role of macrolide therapy in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of death and disability worldwide. The Global Burden of Disease study has concluded that COPD will become the third leading cause of death worldwide by 2020, and will increase its ranking of disability-adjusted life years lost from 12th to 5th. Acute exacerbations of COPD (AECOPD) are associated with impaired quality of life and pulmonary function. More frequent or severe AECOPDs have been associated with especially markedly impaired quality of life and a greater longitudinal loss of pulmonary function. COPD and AECOPDs are characterized by an augmented inflammatory response. Macrolide antibiotics are macrocyclical lactones that provide adequate coverage for the most frequently identified pathogens in AECOPD and have been generally included in published guidelines for AECOPD management. In addition, they exert broad-ranging, immunomodulatory effects both in vitro and in vivo, as well as diverse actions that suppress microbial virulence factors. Macrolide antibiotics have been used to successfully treat a number of chronic, inflammatory lung disorders including diffuse panbronchiolitis, asthma, noncystic fibrosis associated bronchiectasis, and cystic fibrosis. Data in COPD patients have been limited and contradictory but the majority hint to a potential clinical and biological effect. Additional, prospective, controlled data are required to define any potential treatment effect, the nature of this effect, and the role of bronchiectasis, baseline colonization, and other cormorbidities.

Inflammatory profile of new bacterial strain exacerbations of chronic obstructive pulmonary disease

RATIONALE

Whether the airway and systemic inflammatory profile in bacterial exacerbations of chronic obstructive pulmonary disease (COPD) is distinct from nonbacterial exacerbations is unclear. Previous studies have not used molecular typing of bacterial pathogens, which is required to accurately define bacterial infection in COPD. The relationship between clinical severity and course of exacerbation and inflammation is also not fully understood.

OBJECTIVES

To determine if (1) systemic and airway inflammation is distinct in new bacterial strain exacerbations and (2) clinical severity and resolution of exacerbations is related to airway and systemic inflammation.

METHODS

In a prospective longitudinal cohort study in COPD, sputum and serum samples obtained before, at, and following exacerbations during a 2-year period were studied.

MEASUREMENTS AND MAIN RESULTS

Clinical information, molecular typing of bacterial pathogens, sputum IL-8, tumor necrosis factor (TNF)-alpha and neutrophil elastase, and serum C-reactive protein. From 46 patients, 177 exacerbations were grouped as new strain, preexisting strain, other pathogen, and pathogen negative. New strain exacerbations were associated with significantly greater increases from baseline in sputum TNF-alpha and neutrophil elastase, and in serum C-reactive protein compared with the other three groups. Increases in inflammatory markers were similar among the other three groups. Clinical resolution was accompanied by resolution of inflammation to preexacerbation levels, whereas persistent symptoms were paralleled by persistently elevated inflammation. Clinical exacerbation severity was significantly correlated with levels of all four markers.

CONCLUSIONS

Neutrophilic airway inflammation and systemic inflammation are more intense with well-defined bacterial exacerbations than with nonbacterial exacerbations. Clinical course of exacerbation and inflammation are closely linked.

Pathogen-directed therapy in acute exacerbations of chronic obstructive pulmonary disease

Acute exacerbations of chronic obstructive pulmonary disease (COPD) are important events in the natural history of this chronic lung disorder. These events can be caused by a large number of infectious and noninfectious agents and are associated with an increased local and systemic inflammatory response. Their frequency and severity have been linked to progressive deterioration in lung function and health status. Infectious pathogens ranging from viral to atypical and typical bacteria have been implicated in the majority of episodes. Most therapeutic regimens to date have emphasized broad, nonspecific approaches to bronchoconstriction and pulmonary inflammation. Increasingly, therapy that targets specific etiologic pathogens has been advocated. These include clinical and laboratory-based methods to identify bacterial infections. Further additional investigation has suggested specific pathogens within this broad class. As specific antiviral therapies become available, better diagnostic approaches to identify specific pathogens will be required. Furthermore, prophylactic therapy for at-risk individuals during high-risk times may become a standard therapeutic approach. As such, the future will likely include aggressive diagnostic algorithms based on the combination of clinical syndromes and rapid laboratory modalities to identify specific causative bacteria or viruses.

Pseudomonas et bronches

The risk of Pseudomonas aeruginosa (Pa) acquisition, colonization, and infection during chronic bronchial disease varies according to the disease (cystic fibrosis, bronchial dilatation, post-tobacco abuse chronic obstructive bronchopneumonia), its evolutive stage, and a number of known or suspected factors. The involvement of Pa marks an important evolution of the disease, well demonstrated in cystic fibrosis. P. aeruginosa can adhere to epithelial cells (initial colonization) then organizes itself in complex structures evolving from simples microcolonies to macrocolonies in a structured biofilm supporting chronic colonization. P. aeruginosa can produce several factors of virulence, leading to the permanent destruction of host cells, thus inducing the regular liberation of pro-inflammatory mediators implementing a vicious circle worsening these chronic respiratory diseases and favoring their exacerbation. Chronic Pa suppuration has a systemic impact and justifies a global multidisciplinary management. In cystic fibrosis, the presence of P. aeruginosa is a major prognostic element. The current consensus is to detect the primary colonization as early as possible eradication is still possible and to treat it before it evolves to chronicity. But right now, this type of management has not been justified for other chronic bronchial diseases.

Airway bacterial concentrations and exacerbations of chronic obstructive pulmonary disease

RATIONALE

Increased bacterial concentration (load) in the lower airways and new bacterial strain acquisition have been posited as mechanisms for chronic obstructive pulmonary disease (COPD) exacerbations. Bacterial concentrations are higher during exacerbation than during stable disease; however, these studies are cross sectional and devoid of strain typing.

OBJECTIVES

To determine if the increased bacterial concentrations function as a separate mechanism for exacerbation induction independent of new strain acquisition.

METHODS

In a prospective, longitudinal cohort of patients with COPD, the relationship between exacerbation occurrence, sputum bacterial concentrations, and new strain acquisition was examined.

MEASUREMENTS AND MAIN RESULTS

Clinical information, quantitative sputum cultures, and molecular typing of potential bacterial pathogen isolates. Over 81 months, 104 subjects completed 3,009 clinic visits, 560 (19.6%) during exacerbations and 2,449 (80.4%) during stable disease. Among preexisting strains, sputum concentrations of Nontypeable Haemophilus influenzae and Haemophilus haemolyticus were not different in exacerbation versus stable disease. Moraxella catarrhalis (stable, 10(8.38 +/- 0.13) [mean +/- SEM] vs. exacerbation, 10(7.78 +/- 0.26); p = 0.02) and Streptococcus pneumoniae (stable, 10(8.42 +/- 0.21) vs. exacerbation, 10(7.76 +/- 0.52); p = 0.07) concentrations were lower during exacerbations compared with stable periods. Concentrations of new strains of H. influenzae (stable, 10(7.28 +/- 0.15) vs. exacerbation, 10(7.76 +/- 0.17); p = 0.04) and M. catarrhalis (stable, 10(7.85 +/- 0.15) vs. exacerbation, 10(8.37 +/- 0.14); p = 0.02), were increased during exacerbations; however, the differences were small.

CONCLUSIONS

Change in bacterial load is unlikely to be an important mechanism for exacerbations. Better understanding of the host-pathogen interaction, rather than enumerating bacteria in respiratory samples, is required to provide new insights into bacterial infection in COPD.

[Bacterial etiology of chronic bronchitis exacerbations treated by primary care physicians]

OBJECTIVE

Few studies have been carried out to determine the prevalence of microorganisms causing exacerbations of chronic bronchitis in the community setting. The aim of the present study was to determine the bacterial etiology of chronic bronchitis exacerbations in patients not requiring hospitalization.

PATIENTS AND METHODS

This observational, cross-sectional, multicenter study was carried out at the primary care level during 2 weeks (in November 2001 and January 2002). All laboratory work was carried out at a single center. We studied 1,947 patients with mild-moderate exacerbations treated by 650 primary care physicians. All the sputum samples received for centralized processing were subject to Gram staining, microscopic examination, and bacterial culture.

RESULTS

Out of 1,537 cultures of sputum samples collected, 498 had good cell quality for microscopic examination (32.4%). Of the 498 good quality samples analyzed, 246 (49.4%) were positive and 468 isolates were obtained. The most commonly isolated germ was Streptococcus pneumoniae (163 cases, 34.8%), followed by Moraxella catarrhalis (112, 23.9%), and Haemophilus influenzae (59, 12.6%). In 1.2% of the S. pneumoniae isolates resistance was found to amoxicillin; resistance to macrolides was found in 34.3%. The antibiotics most commonly prescribed, however, were macrolides (38.3% of the prescriptions).

CONCLUSIONS

S. pneumoniae was the microorganism most frequently isolated in cases of chronic bronchitis exacerbation treatable in this outpatient setting.

Tratamiento farmacológico de las agudizaciones infecciosas de la EPOC

Las agudizaciones de la enfermedad pulmonar obstructiva crónica (EPOC) son episodios frecuentes y potencialmente graves, que dejan un impacto permanente en la calidad de vida y en la función pulmonar de los pacientes. Hasta un 75% de las agudizaciones tiene una etiología bacteriana, en ocasiones asociada a infección vírica. La tasa de fracaso del tratamiento ambulatorio de las agudizaciones alcanza el 20-25% y la gravedad de la enfermedad de base es el principal factor de riesgo de fracaso. La colonización bacteriana persistente es un factor de riesgo de agudizaciones frecuentes y graves, y de más rápida progresión de la EPOC. Por este motivo el tratamiento antibiótico de las agudizaciones debe perseguir no sólo la curación clínica, sino también la mejor erradicación posible para acelerar la recuperación y prevenir las recaídas. Nuevos ensayos clínicos han demostrado que el antibiótico que consigue una mejor erradicación puede prolongar el tiempo sin síntomas de agudización.

Comment évaluer, orienter et suivre un patient ayant une pneumonie aiguë communautaire ? Une exacerbation de bronchopneumopathie chronique obstructive ?

L'objectif de cette revue est de présenter une analyse bibliographique de la littérature de ces cinq dernières années concernant les pneumonies aiguës communautaires (PAC) et les exacerbations aiguës de bronchopneumopathies chroniques obstructives (EABPCO). La PAC et l'EABPCO sont des pathologies fréquentes grevées d'une mortalité et/ou morbidité encore élevée de nos jours. La connaissance des facteurs de risque d'évolution compliquée et l'identification des signes de gravité souvent liés au risque de mortalité permettent d'orienter le patient pour un traitement ambulatoire, en hospitalisation conventionnelle ou en secteur de réanimation ; des règles prédictives ont été établies dans ce sens. La littérature concernant les critères de sortie d'hospitalisation et le suivi des patients est plus pauvre.