Pseudomonas aeruginosaresistance patterns and clinical outcomes in hospitalized exacerbations of COPD

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

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

Genomic and metabolic versatility of Pseudomonas aeruginosa contributes to its inter-kingdom transmission and survival

Pseudomonas aeruginosa is one of the most versatile bacteria with renowned pathogenicity and extensive drug resistance. The diverse habitats of this bacterium include fresh, saline and drainage waters, soil, moist surfaces, taps, showerheads, pipelines, medical implants, nematodes, insects, plants, animals, birds and humans. The arsenal of virulence factors produced by P. aeruginosa includes pyocyanin, rhamnolipids, siderophores, lytic enzymes, toxins and polysaccharides. All these virulent elements coupled with intrinsic, adaptive and acquired antibiotic resistance facilitate persistent colonization and lethal infections in different hosts. To date, treating pulmonary diseases remains complicated due to the chronic secondary infections triggered by hospital-acquired P. aeruginosa. On the contrary, this bacterium can improve plant growth by suppressing phytopathogens and insects. Notably, P. aeruginosa is one of the very few bacteria capable of trans-kingdom transmission and infection. Transfer of P. aeruginosa strains from plant materials to hospital wards, animals to humans, and humans to their pets occurs relatively often. Recently, we have identified that plant-associated P. aeruginosa strains could be pathologically similar to clinical isolates. In this review, we have highlighted the genomic and metabolic factors that facilitate the dominance of P. aeruginosa across different biological kingdoms and the varying roles of this bacterium in plant and human health.

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

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

Antioxidant and Anti-Inflammatory Effects of Thyme (Thymus vulgaris L.) Essential Oils Prepared at Different Plant Phenophases on Pseudomonas aeruginosa LPS-Activated THP-1 Macrophages

Thyme (Thymus vulgaris L.) essential oil (TEO) is widely used as an alternative therapy especially for infections of the upper respiratory tract. TEO possesses antiviral, antibacterial, and antifungal properties. The emerging antibiotic resistance of bacterial strains, including Pseudomonas aeruginosa, has prompted the urge to find alternative treatments. In the present study, we examined the anti-inflammatory and antioxidant effects of thymol, the main compound of TEO, and two TEOs prepared at the beginning and at the end of the flowering period that may make these oils promising candidates as complementary or alternative therapies against P. aeruginosa infections. The activity measurements of the antioxidant enzymes peroxidase (PX), catalase (CAT), and superoxide dismutase (SOD) as well as the determination of total antioxidant capacity of P. aeruginosa-activated THP-1 cells revealed that thymol and both TEOs increased CAT and SOD activity as well as the antioxidant capacity of the THP-1 cells. The measurements of the proinflammatory cytokine mRNA expression and secreted protein level of LPS-activated THP-1 cells showed that from the two TEOs, only TEO prepared at the beginning of the flowering period acted as a potent inhibitor of the synthesis of IL-6, IL-8, IL-β, and TNF-α. Our results suggest that not only thymol, but also the synergism or the antagonistic effects of the additional compounds of the essential oils are responsible for the anti-inflammatory activity of TEOs.

Role of Host and Bacterial Lipids in Pseudomonas aeruginosa Respiratory Infections

The opportunistic pathogen Pseudomonas aeruginosa is one of the most common agents of respiratory infections and has been associated with high morbidity and mortality rates. The ability of P. aeruginosa to cause severe respiratory infections results from the coordinated action of a variety of virulence factors that promote bacterial persistence in the lungs. Several of these P. aeruginosa virulence mechanisms are mediated by bacterial lipids, mainly lipopolysaccharide, rhamnolipid, and outer membrane vesicles. Other mechanisms arise from the activity of P. aeruginosa enzymes, particularly ExoU, phospholipase C, and lipoxygenase A, which modulate host lipid signaling pathways. Moreover, host phospholipases, such as cPLA2α and sPLA2, are also activated during the infectious process and play important roles in P. aeruginosa pathogenesis. These mechanisms affect key points of the P. aeruginosa-host interaction, such as: i) biofilm formation that contributes to bacterial colonization and survival, ii) invasion of tissue barriers that allows bacterial dissemination, iii) modulation of inflammatory responses, and iv) escape from host defenses. In this mini-review, we present the lipid-based mechanism that interferes with the establishment of P. aeruginosa in the lungs and discuss how bacterial and host lipids can impact the outcome of P. aeruginosa respiratory infections.

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

Background

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

Results

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

Conclusions

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

Pseudomonas aeruginosa Pneumonia: Evolution of Antimicrobial Resistance and Implications for Therapy

Pseudomonas aeruginosa (PA), a non-lactose-fermenting gram-negative bacillus, is a common cause of nosocomial infections in critically ill or debilitated patients, particularly ventilator-associated pneumonia (VAP), and infections of urinary tract, intra-abdominal, wounds, skin/soft tissue, and bloodstream. PA rarely affects healthy individuals, but may cause serious infections in patients with chronic structural lung disease, comorbidities, advanced age, impaired immune defenses, or with medical devices (e.g., urinary or intravascular catheters, foreign bodies). Treatment of pseudomonal infections is difficult, as PA is intrinsically resistant to multiple antimicrobials, and may acquire new resistance determinants even while on antimicrobial therapy. Mortality associated with pseudomonal VAP or bacteremias is high (> 35%) and optimal therapy is controversial. Over the past three decades, antimicrobial resistance (AMR) among PA has escalated globally, via dissemination of several international multidrug resistant "epidemic" clones. We discuss the importance of PA as a cause of pneumonia including health care-associated pneumonia, hospital-acquired pneumonia, VAP, the emergence of AMR to this pathogen, and approaches to therapy (both empirical and definitive).

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

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

Impact of Pseudomonas aeruginosa Infection on Patients with Chronic Inflammatory Airway Diseases

Pseudomonas aeruginosa (P. aeruginosa) is a ubiquitous and opportunistic microorganism and is considered one of the most significant pathogens that produce chronic colonization and infection of the lower respiratory tract, especially in people with chronic inflammatory airway diseases such as asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), and bronchiectasis. From a microbiological viewpoint, the presence and persistence of P. aeruginosa over time are characterized by adaptation within the host that precludes any rapid, devastating injury to the host. Moreover, this microorganism usually develops antibiotic resistance, which is accelerated in chronic infections especially in those situations where the frequent use of antimicrobials facilitates the selection of “hypermutator P. aeruginosa strain”. This phenomenon has been observed in people with bronchiectasis, CF, and the “exacerbator” COPD phenotype. From a clinical point of view, a chronic bronchial infection of P. aeruginosa has been related to more severity and poor prognosis in people with CF, bronchiectasis, and probably in COPD, but little is known on the effect of this microorganism infection in people with asthma. The relationship between the impact and treatment of P. aeruginosa infection in people with airway diseases emerges as an important future challenge and it is the most important objective of this review.

Pharmacotherapeutic management of bronchial infections in adults: non-cystic fibrosis bronchiectasis and chronic obstructive pulmonary disease

INTRODUCTION

Effective management of both acute and chronic bronchial infections is mandatory due to their high frequency rate, the relevant morbidity and mortality and the significant burden to health care systems, especially with the aging of population. Bacteria are the main causative pathogens, followed by viruses, and less commonly by fungi. The clinical evaluation of new therapeutic associations is mandatory to cope with the increases in resistance, in association with better infection control and antimicrobial policies.

AREAS COVERED

The authors searched Medline for any article published in English language up until March 1, 2020 that concerns the treatment of acute exacerbations and chronic infections in chronic obstructive respiratory disease and bronchiectasis.

EXPERT OPINION

As acute exacerbations are a main common and detrimental event in patients with COPD and bronchiectasis, effective antimicrobial therapies and regimens should be optimized. The development of new molecules or combination regimens is vital to patients with severe and/or difficult-to-treat infections. Moreover, chronic infection control is mandatory in these patients to their improve quality of life, respiratory function and prognosis as well as for reducing health care costs.

Why is Disease Penetration so Variable in Alpha-1 Antitrypsin Deficiency? The Contribution of Environmental Factors

Environmental influences on clinical phenotype in alpha-1 antitrypsin deficiency (AATD) include cigarette smoke, occupational exposures, airway/sputum bacteria and outdoor air pollution. This narrative review describes the impact of the major environmental exposures and summarizes their effect on clinical phenotype and outcomes. In general, patients with AATD are more susceptible to pulmonary damage as a result of the relatively unopposed action of neutrophil elastase, in the context of neutrophilic inflammation stimulated by environmental factors. However, the amount of phenotypic variability explicable by environmental factors is insufficient to account for the wide range of clinical presentations observed, suggesting that a combination of genetic and environmental factors is likely to be responsible.

Current Challenges in Chronic Bronchial Infection in Patients with Chronic Obstructive Pulmonary Disease

Currently, chronic obstructive pulmonary disease (COPD) patients and their physicians face a number of significant clinical challenges, one of which is the high degree of uncertainty related to chronic bronchial infection (CBI). By reviewing the current literature, several challenges can be identified, which should be considered as goals for research. One of these is to establish the bases for identifying the biological and clinical implications of the presence of potentially pathogenic microorganisms in the airways that should be more clearly elucidated according to the COPD phenotype. Another urgent area of research is the role of long-term preventive antibiotics. Clinical trials need to be carried out with inhaled antibiotic therapy to help clarify the profile of those antibiotics. The role of inhaled corticosteroids in patients with COPD and CBI needs to be studied to instruct the clinical management of these patients. Finally, it should be explored and confirmed whether a suitable antimicrobial treatment during exacerbations may contribute to breaking the vicious circle of CBI in COPD. The present review addresses the current state of the art in these areas to provide evidence which will enable us to progressively plan better healthcare for these patients.

Risk factors of chronic obstructive pulmonary disease exacerbations

Chronic Obstructive Pulmonary Disease (COPD) is a chronic respiratory disease characterised by persistent respiratory symptoms and airflow limitation. COPD has a major impact on public health, mainly because of its increasing prevalence, morbidity and mortality. The natural course of COPD is aggravated by episodes of respiratory symptom worsening termed exacerbations that contribute to disease progression. Acute Exacerbations of COPD (AECOPD) can be triggered by a multitude of different factors, including respiratory tract infections, various exposures, prior exacerbations, non-adherence to treatment and associated comorbidities. AECOPD are associated with an inexorable decline of lung function and a significantly worse survival outcome. This review will summarise the most important aspects regarding the impact of different factors that contribute to COPD exacerbations.

Impact of Pseudomonas aeruginosa Isolation on Mortality and Outcomes in an Outpatient Chronic Obstructive Pulmonary Disease Cohort

BACKGROUND

Tracheobronchial colonization by Pseudomonas aeruginosa (PA) has been shown to negatively impact outcomes in cystic fibrosis and bronchiectasis. There is uncertainty whether the same association is prevalent in chronic obstructive pulmonary disease (COPD), especially in the outpatient setting. Our objective was to determine (1) whether PA isolation is associated with mortality and (2) changes in exacerbation and hospitalization rates within a longitudinal cohort of COPD outpatients.

METHODS

Pseudomonas aeruginosa colonization was ascertained in monthly sputum cultures in a prospective cohort of COPD patients from 1994 to 2014. All-cause mortality was compared between patients who were colonized during their follow-up period (PA + ) and those who remained free of colonization (PA - ); Cox proportional hazards models were used. Exacerbation and hospitalization rates were evaluated by 2-rate χ 2 and segmented regression analysis for 12 months before and 24 months after PA isolation.

RESULTS

Pseudomonas aeruginosa was isolated from sputum in 73 of 181 (40%) patients. Increased mortality was seen with PA isolation: 56 of 73 (77%) PA +  patients died compared with 73 of 108 (68%) PA - patients (P = .004). In adjusted models, PA +  patients had a 47% higher risk of mortality (adjusted hazard ratio = 1.47; 95% confidence interval, 1.03-2.11; P = .04). Exacerbation rates were higher for the PA +  group during preisolation (15.4 vs 9.0 per 100 person-months, P < .001) and postisolation periods (15.7 vs 7.5, P < .001). Hospitalization rates were higher during the postisolation period among PA +  patients (6.25 vs 2.44, P < .001).

CONCLUSIONS

Tracheobronchial colonization by PA in COPD outpatients was associated with higher morbidity and mortality. This suggests that PA likely contributes to adverse clinical outcomes rather than just a marker of worsening disease.

Long-term Colonization by Campylobacter jejuni Within a Human Host: Evolution, Antimicrobial Resistance, and Adaptation

Background

Campylobacteriosis is inflammation of the gastrointestinal tract as a result of Campylobacter infection. Most campylobacteriosis cases are acute and self-limiting, with Campylobacter excretion ceasing a few weeks after symptoms cease. We identified a patient with fecal specimens positive for Campylobacter jejuni (ST45) intermittently during a 10-year period.

Methods

Sixteen Campylobacter isolates were collected from the patient during 2006-2016. The isolates' genomes were sequenced to determine their relatedness, and their antimicrobial susceptibility patterns and motility were measured to determine the effects of antibiotic therapy and long-term excretion on the Campylobacter population.

Results

Phylogenetic analyses estimated that the isolates shared a date of common ancestor between 1998 and 2006, coinciding with the onset of symptoms for the patient. Genomic analysis identified selection for changes in motility, and antimicrobial susceptibility testing suggested that the Campylobacter population developed resistance to several antibiotics coinciding with periods of antibiotic therapy.

Conclusions

The patient was consistently colonized with organisms from a Campylobacter population that adapted to the internal environment of the patient. Genomic and phylogenetic analyses can give insight into a patient's infection history and the effect of antimicrobial treatment on Campylobacter populations in this unusual situation of long-term colonization of an individual.

Clinical variables predicting the risk of a hospital stay for longer than 7 days in patients with severe acute exacerbations of chronic obstructive pulmonary disease: a prospective study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) patients may experience an acute exacerbation (AECOPD) that requires hospitalisation. The length of hospital stay (LHS) has a great economic impact on the health-care system. Knowing the predictors of prolonged LHS could help to identify possible interventions.

METHODS

We performed a prospective study to identify the clinical predictors of prolonged LHS in patients hospitalised for AECOPD. We divided the study sample by LHS into normal (≤7 days) and prolonged LHS (> 7 days) groups. Outcomes were the need for non-invasive and invasive mechanical ventilation (NIMV and IMV), intensive care unit (ICU) admission, and the 3-year mortality.

RESULTS

We enrolled 437 patients, of which 213 and 224 had normal LHS and prolonged LHS, respectively. Patients with a prolonged LHS had more prior hospitalisations for AECOPD, a worse mMRC (modified Medical Research Council) dyspnoea score, a higher prevalence of long-term oxygen therapy and a higher rate of congestive heart disease. During the current admission, this group also tended to require NIMV, IMV and ICU admission and the mortality risks at 6 months, 1 year and 3 years were higher. In the multivariate regression analysis, an mMRC dyspnoea score ≥ 2 (odds ratio-OR 2.24; 95% confidence interval-CI 1.34 to 3.74; p = 0.002) and the presence of acute respiratory acidosis (OR 2.75; 95% CI 1.49 to 5.05; p = 0.001) predicted a prolonged LHS at admission.

CONCLUSIONS

The presence of an mMRC ≥2 and acute respiratory acidosis at admission independently increased the risk of a prolonged LHS for AECOPD.

Appropriate antibiotic management of bacterial lower respiratory tract infections

Lower respiratory tract infections are the leading cause of infectious disease deaths worldwide and are the fifth leading cause of death overall. This is despite conditions such as pneumococcal infections and influenza being largely preventable with the use of appropriate vaccines. The mainstay of treatment for the most important bacterial lower respiratory tract infections, namely acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and community-acquired pneumonia (CAP), is the use of antibiotics. Yet despite a number of recent publications, including clinical studies as well as several systematic literature reviews and meta-analyses, there is considerable ongoing controversy as to what the most appropriate antibiotics are for the empiric therapy of CAP in the different settings (outpatient, inpatient, and intensive care unit). Furthermore, in the case of AECOPD, there is a need for consideration of which of these exacerbations actually need antibiotic treatment. This article describes these issues and makes suggestions for appropriately managing these conditions, in the setting of the need for antimicrobial stewardship initiatives designed to slow current emerging rates of antibiotic resistance, while improving patient outcomes.

Microorganisms resistant to conventional antimicrobials in acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Antimicrobial treatment for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) remains controversial. In some cases AECOPD are caused by microorganisms that are resistant to treatments recommended by guidelines. Our aims were: 1) identify the risk factors associated with infection by microorganisms resistant to conventional treatment (MRCT), 2) Compare the clinical characteristics and outcomes of patients with AECOPD resulting from MRCT against those with AECOPD from other causes.

METHODS

We prospective analysed a cohort of patients admitted with severe AECOPD (2009 to 2015) who were assigned to three groups: patients with MRCT (those patients with germs resistant to antibiotics recommended in guidelines), patients with microorganisms sensitive to conventional antimicrobial treatment (MSCT), and patients with negative microbiology results who had not previously received antibiotics. Multinomial logistic regression analyses were used to examine the associations between microbial aetiology groups and risk factors. The association between LOS and risk factors was also tested in simple and multiple analyses, and similar inclusion criteria were applied for the linear regression analysis.

RESULTS

Of the 451 patients admitted, 195 patients (43%) were included. Respiratory cultures were positive in 86(44%) and negative in 109(56%). MRCT were isolated in 34 cases (40%) and MSCT in 52 (60%). Patients with MRCT had more AECOPD in the previous year, received more antibiotic treatment in the previous three months, had more severe disease, higher dyspnoea and a positive respiratory culture in the previous year (mainly for Pseudomonas aeruginosa). The following conditions were independent factors for MRCT isolation: non-current smoker (odds ratio [OR] 4.19 [95% confidence interval [CI] 1.29-13.67], p = 0.017), ≥ 2 AECOPD or ≥ 1 admission for AECOPD in the previous year (OR 4.13 [95% CI 1.52-11.17], p = 0.005), C-reactive protein < 5 mg/dL; (OR 3.58 [95% CI 1.41-9.07], p = 0.007). Mortality rates were comparable at 30-days, one year and 3 years; however, patients in the MRCT group had longer hospital stays.

CONCLUSION

In conclusion, there are risk factors for resistant germs in AECOPD; however, the presence of these germs does not increase mortality. Patients with isolation of MRCT had longer length of stay.

Antibiotic-resistant Pseudomonas aeruginosa infection in patients with bronchiectasis: prevalence, risk factors and prognostic implications

Background and aims

Pseudomonas aeruginosa (PA) is the most common pathogen in bronchiectasis and frequently develops resistance to multiple classes of antibiotics, but little is known about the clinical impacts of PA-resistant (PA-R) isolates on bronchiectasis. We, therefore, investigated the prevalence, risk factors and prognostic implications of PA-R isolates in hospitalized bronchiectasis patients.

Patients and methods

Between June 2011 and July 2016, data from adult bronchiectasis patients isolated with PA at the First Affiliated Hospital of Zhengzhou University were retrospectively analyzed. PA was classified as PA-R in case antibiogram demonstrated resistance on at least one occasion.

Results

Seven hundred forty-seven bronchiectasis patients were assessed. Of these, 147 (19.7%) had PA isolate in the sputum or bronchoscopic culture. PA-R and PA-sensitive accounted for 88 (59.9%) and 59 (31.1%) patients, respectively. In multivariate model, factors associated with PA-R isolate in bronchiectasis included prior exposure to antibiotics (odds ratio [OR] =6.18), three or more exacerbations in the previous year (OR =2.81), higher modified Medical Research Council dyspnea scores (OR =1.93) and greater radiologic severity (OR =1.15). During follow-up (median: 26 months; interquartile range: 6–59 months), 36 patients died, of whom 24 (66.7%) had PA-R isolate at baseline. However, PA-R isolate was not associated with greater all-cause mortality in bronchiectasis.

Conclusion

PA-R infection is common among bronchiectasis patients, mainly determined by prior exposure to antibiotics, frequent exacerbations, more pronounced dyspnea and more severe radiologic involvement. However, PA-R isolate is not an independent risk factor for all-cause mortality in bronchiectasis.

Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis Defect

INTRODUCTION

Cigarette smoke (CS) exposure is the leading risk factor for COPD-emphysema pathogenesis. A common characteristic of COPD is impaired phagocytosis that causes frequent exacerbations in patients leading to increased morbidity. However, the underlying mechanism is unclear. Hence, we investigated if CS exposure causes autophagy impairment as a mechanism for diminished bacterial clearance via phagocytosis by utilizing murine macrophages (RAW264.7 cells) and Pseudomonas aeruginosa (PA01-GFP) as an experimental model.

METHODS

Briefly, RAW cells were treated with cigarette smoke extract (CSE), chloroquine (autophagy inhibitor), TFEB-shRNA, CFTR(inh)-172, and/or fisetin prior to bacterial infection for functional analysis.

RESULTS

Bacterial clearance of PA01-GFP was significantly impaired while its survival was promoted by CSE (p < 0.01), autophagy inhibition (p < 0.05; p < 0.01), TFEB knockdown (p < 0.01; p < 0.001), and inhibition of CFTR function (p < 0.001; p < 0.01) in comparison to the control group(s) that was significantly recovered by autophagy-inducing antioxidant drug, fisetin, treatment (p < 0.05; p < 0.01; and p < 0.001). Moreover, investigations into other pharmacological properties of fisetin show that it has significant mucolytic and bactericidal activities (p < 0.01; p < 0.001), which warrants further investigation.

CONCLUSIONS

Our data suggests that CS-mediated autophagy impairment as a critical mechanism involved in the resulting phagocytic defect, as well as the therapeutic potential of autophagy-inducing drugs in restoring is CS-impaired phagocytosis.

The respiratory threat posed by multidrug resistant Gram-negative bacteria

Respiratory infections are a major cause of global mortality and morbidity. In recent years, an increased incidence of multidrug-resistant (MDR) Gram-negative bacteria (GNB) has been described. Microorganisms such as Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae or Acinetobacter baumannii have been identified as causative pathogens of different respiratory tract infections. Several studies have detected MDR-GNB in patients with community-acquired and nosocomial pneumonia. Furthermore, MDR-GNB have also been isolated in patients with chronic obstructive pulmonary disease and bronchiectasis having acute or chronic bronchial infection. Prevalence varies depending on the geographical area but MDR-GNB has been reported in the Asia-Pacific region, Europe and the United States, reaching rates of 70% in hospital-acquired infection. The presence of MDR-GNB has been related to poor clinical outcomes, including increased mortality, although data regarding this relationship are limited. This is probably linked to inappropriate selection of empiric antibiotic treatment; this poses a threat of widespread resistance. GNB antibiotic resistance and the absence of new antibiotics are a major concern given limited treatment options; an aspect that deserves future research. We review current literature, highlight prevalence of MDR-GNB in different respiratory infections and explore their impact on clinical outcomes.

The role of acute and chronic respiratory colonization and infections in the pathogenesis of COPD

COPD is a major global concern, increasingly so in the context of ageing populations. The role of infections in disease pathogenesis and progression is known to be important, yet the mechanisms involved remain to be fully elucidated. While COPD pathogens such as Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae are strongly associated with acute exacerbations of COPD (AECOPD), the clinical relevance of these pathogens in stable COPD patients remains unclear. Immune responses in stable and colonized COPD patients are comparable to those detected in AECOPD, supporting a role for chronic colonization in COPD pathogenesis through perpetuation of deleterious immune responses. Advances in molecular diagnostics and metagenomics now allow the assessment of microbe-COPD interactions with unprecedented personalization and precision, revealing changes in microbiota associated with the COPD disease state. As microbial changes associated with AECOPD, disease severity and therapeutic intervention become apparent, a renewed focus has been placed on the microbiology of COPD and the characterization of the lung microbiome in both its acute and chronic states. Characterization of bacterial, viral and fungal microbiota as part of the lung microbiome has the potential to reveal previously unrecognized prognostic markers of COPD that predict disease outcome or infection susceptibility. Addressing such knowledge gaps will ultimately lead to a more complete understanding of the microbe-host interplay in COPD. This will permit clearer distinctions between acute and chronic infections and more granular patient stratification that will enable better management of these features and of COPD.

Exacerbations in COPD Patients with Bronchiectasis

There is evidence that coexisting bronchiectasis (BE) in patients with chronic obstructive pulmonary disease (COPD) aggravates the course of the disease. In this study, we aimed to evaluate the frequency and severity of bacterial exacerbations in COPD patients with BE. The frequency and duration of bacterial exacerbations treated in a 12-month period, as well as the duration of the exacerbation-free interval, were evaluated in 54 patients with COPD (Group D) who were diagnosed and assessed according to official recommendations. In 27 patients, BE was diagnosed by high-resolution computed tomography (HRCT), whereas an equal number of COPD patients who were confirmed negative for BE by HRCT, served as controls. We found a significantly higher mean number of exacerbations in a 12-month period in COPD patients with BE (2.9 ± 0.5), as compared to their mean number in controls (2.5 ± 0.3) (p = 0.0008). The mean duration of exacerbation, i.e. the mean number of days elapsed before complete resolution of the symptoms or their return to the baseline severity, was significantly longer in COPD patients with BE as compared to their mean duration in controls (6.9 ± 1.8 vs. 5.7 ± 1.4; p = 0.0085). In addition, the mean exacerbation-free interval expressed in days, in patients with COPD with BE, was significantly shorter than in COPD patients in whom BE were excluded (56.4 ± 17.1 vs. 67.2 ± 14.3; p = 0.0149). Overall, our findings indicate that coexisting BE in COPD patients may lead to more frequent exacerbations with a longer duration.

Global impact of bronchiectasis and cystic fibrosis

EDUCATIONAL AIMS

To recognise the clinical and radiological presentation of the spectrum of diseases associated with bronchiectasis.To understand variation in the aetiology, microbiology and burden of bronchiectasis and cystic fibrosis across different global healthcare systems.

Bronchiectasis is the term used to refer to dilatation of the bronchi that is usually permanent and is associated with a clinical syndrome of cough, sputum production and recurrent respiratory infections. It can be caused by a range of inherited and acquired disorders, or may be idiopathic in nature. The most well recognised inherited disorder in Western countries is cystic fibrosis (CF), an autosomal recessive condition that leads to progressive bronchiectasis, bacterial infection and premature mortality. Both bronchiectasis due to CF and bronchiectasis due to other conditions are placing an increasing burden on healthcare systems internationally. Treatments for CF are becoming more effective leading to more adult patients with complex healthcare needs. Bronchiectasis not due to CF is becoming increasingly recognised, particularly in the elderly population. Recognition is important and can lead to identification of the underlying cause, appropriate treatment and improved quality of life. The disease is highly diverse in its presentation, requiring all respiratory physicians to have knowledge of the different "bronchiectasis syndromes". The most common aetiologies and presenting syndromes vary depending on geography, with nontuberculous mycobacterial disease predominating in some parts of North America, post-infectious and idiopathic disease predominating in Western Europe, and post-tuberculosis bronchiectasis dominating in South Asia and Eastern Europe. Ongoing global collaborative studies will greatly advance our understanding of the international impact of bronchiectasis and CF.