Challenges in managing Pseudomonas aeruginosa in non-cystic fibrosis bronchiectasis

Yinhuang buccal tablet alters airway microbiota composition and metabolite profile in healthy humans

ETHNOPHARMACOLOGICAL RELEVANCE

Perturbations in airway microbiota composition and disruption of microbe-metabolite interactions have been observed in respiratory infectious diseases (RIDs). The Yinhuang (YH) buccal tablet, as an ancient Chinese medicinal formula, has been traditionally employed for the management of upper RIDs. However, there is a lack of evidence for the effects of YH buccal tablets on upper respiratory tract microbiota and circulating metabolites.

AIM OF THE STUDY

The aim of this study was to analyze the changes in respiratory microbiota composition and circulating metabolite profile after YH buccal tablets administration.

MATERIALS AND METHODS

Throat swab samples and serum samples were collected from 60 healthy subjects for high-throughput 16S ribosomal RNA gene (16S rRNA) sequencing and non-targeted Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis.

RESULTS

Airway microbial composition changed significantly after YH administration. The abundance of Actinomyces and Prevotella_7 increased, while the abundance of potentially pathogenic Pseudomonas and Corynebacterium decreased. A total of 168 significant HMDB taxonomic metabolites were identified in serum samples, of which lipid metabolites accounted for the largest proportion. Correlation analysis showed that circulatory metabolites were significantly correlated with changes in airway microbiota composition.

CONCLUSIONS

YH buccal tablets can inhibit opportunistic pathogens, increase beneficial microorganisms in the upper respiratory tract, and regulate the body's metabolic pathways. These findings provide insights into the mechanism of action of YH buccal tablets in the treatment and prevention of respiratory diseases.

Impact of Pseudomonas aeruginosa on resource utilization and costs in patients with exacerbated non-cystic fibrosis bronchiectasis

AIMS

Non-cystic fibrosis bronchiectasis (NCFB) is a chronic progressive respiratory disorder occurring at a rate ranging from 4.2 to 278.1 cases per 100,000 persons, depending on age, in the United States. For many patients with NCFB, the presence of Pseudomonas aeruginosa (PA) makes treatment more complicated and typically has worse outcomes. Management of NCFB can be challenging, warranting a better understanding of the burden of illness for NCFB, treatments applied, healthcare resources used, and subsequent treatment costs. Comparing patients diagnosed with exacerbated NCFB, with or without PA on antibiotic utilization, treatments, and healthcare resources utilization and costs was the purpose of this study.

MATERIALS AND METHODS

This was a retrospective cohort study of commercial claims from IQVIA's PharMetrics Plus database (January 1,2006-December 31, 2020). Study patients with a diagnosis of NCFB were stratified into two groups based on the presence or absence of PA, then followed to identify demographic characteristics, comorbid conditions, antibiotic treatment regimen prescribed, healthcare resources utilized, and costs of care.

RESULTS

The results showed that patients with exacerbated NCFB who were PA+ had significantly more oral antibiotic fills per patient per year, more inpatient admissions with a longer length of stay, and more outpatient encounters than those who were PA-. For costs, PA+ patients also had significantly greater total healthcare costs per patient when compared to those who were PA-.

CONCLUSION

Exacerbated NCFB with PA+ was associated with increased antibiotic usage, greater resource utilization, and increased costs. The major contributor to the cost differences was the use of inpatient services. Treatment strategies aimed at reducing the need for inpatient treatment could lessen the disparities observed in patients with NCFB.

A phase 4 multicentre, 2×2 factorial randomised, double-blind, placebo-controlled trial to investigate the efficacy and safety of tobramycin inhalation solution for Pseudomonas aeruginosa eradication in bronchiectasis: ERASE

Chronic Pseudomonas aeruginosa (PA) infection significantly contributes to morbidity and mortality in bronchiectasis patients. Initiating antibiotics early may lead to the eradication of PA. Here we outline the design of a trial (ERASE; NCT06093191) assessing the efficacy and safety of inhaled tobramycin, alone or with oral ciprofloxacin, in bronchiectasis patients with a new isolation of PA. This multicentre, 2×2 factorial randomised, double-blind, placebo-controlled, parallel-group trial includes a 2-week screening period, a 12-week treatment phase (with a combination of ciprofloxacin or a placebo at initial 2 weeks) and a 24-week follow-up. 364 adults with bronchiectasis and a new PA isolation will be randomly assigned to one of four groups: placebo (inhaled saline and ciprofloxacin placebo twice daily), ciprofloxacin alone (750 mg ciprofloxacin and inhaled saline twice daily), inhaled tobramycin alone (inhaled 300 mg tobramycin and ciprofloxacin placebo twice daily) or a combination of both drugs (inhaled 300 mg tobramycin and 750 mg ciprofloxacin twice daily). The primary objective of this study is to assess the proportion of patients successfully eradicating PA in each group by the end of the study. Efficacy will be evaluated based on the eradication rate of PA at other time points (12, 24 and 36 weeks), the occurrence of exacerbations and hospitalisations, time to first pulmonary exacerbations, patient-reported outcomes, symptom measures, pulmonary function tests and the cost of hospitalisations. To date no randomised trial has evaluated the benefit of different PA eradication strategies in bronchiectasis patients. The ERASE trial will therefore generate crucial data to inform future clinical guidelines.

Efficacy of a Pseudomonas aeruginosa serogroup O9 vaccine

There are currently no approved vaccines against the opportunistic pathogen Pseudomonas aeruginosa. Among vaccine targets, the lipopolysaccharide (LPS) O antigen of P. aeruginosa is the most immunodominant protective candidate. There are 20 different O antigens composed of different repeat sugar structures conferring serogroup specificity, and 10 are found most frequently in infection. Thus, one approach to combat infection by P. aeruginosa could be to generate immunity with a vaccine cocktail that includes all these serogroups. Serogroup O9 is 1 of the 10 serogroups commonly found in infection, but it has never been developed into a vaccine, due in part to the acid-labile nature of the O9 polysaccharide. Our laboratory has previously shown that intranasal administration of an attenuated Salmonella strain expressing the P. aeruginosa serogroup O11 LPS O antigen was effective in clearing bacteria and preventing mortality in mice following intranasal challenge with serogroup O11 P. aeruginosa. Consequently, we set out to develop a P. aeruginosa serogroup O9 vaccine using a similar approach. Here, we show that Salmonella expressing serogroup O9 triggered an antibody-mediated immune response following intranasal administration to mice and that it conferred protection from P. aeruginosa serogroup O9 in a murine model of acute pneumonia.

A systematic review on the use of bacteriophage in treating Staphylococcus aureus and Pseudomonas aeruginosa infections in cystic fibrosis

BACKGROUND

Respiratory infections caused by Staphylococcus aureus and Pseudomonas aeruginosa are a major concern for cystic fibrosis (CF) patients due to increasing antibiotic resistance. Bacteriophages, which are viruses that selectively target and kill bacteria, are being studied as an alternative treatment for these infections. This systematic review evaluates the safety and effectiveness of bacteriophages for the treatment of CF-related infections caused by S. aureus and/or P. aeruginosa. We conducted a search for original, published articles in the English language up to March 2023. Studies that administered bacteriophages via intravenous, nebulised, inhaled, or intranasal routes were included, with no comparators required. In vitro and in vivo studies were eligible for inclusion, and only animal in vivo studies that utilised a CF transmembrane conductance regulator (CFTR) animal model were included. Bacteriophage treatment resulted in a decrease in bacterial load in both humans and animals infected with P. aeruginosa. Complete eradication of P. aeruginosa was only observed in one human subject. Additionally, there was a reduction in biofilm, improvement in resistance profile, and reduced pulmonary exacerbations in individual case reports. Evidence suggests that bacteriophage therapy may be a promising treatment option for CF-related infections caused by P. aeruginosa and S. aureus. However, larger and more robust trials are needed to establish its safety and efficacy and create necessary evidence for global legislative frameworks.

Bronchiectasis

Bronchiectasis is a final common pathway of a wide variety of underlying conditions including infectious, autoimmune, allergic, genetic and inflammatory conditions. Patients experience a chronic disease with variable clinical symptoms and course, but most experience cough, sputum production and recurrent exacerbations. Symptoms of bronchiectasis lead to poor quality of life and exacerbations are the major driver of morbidity and mortality. Patients are often chronically infected with bacteria with the most common being Pseudomonas aeruginosa and Haemophilus influenzae. Treatment of bronchiectasis includes standardised testing to identify the underlying cause with targeted treatment if immune deficiency, allergic bronchopulmonary aspergillosis or non-tuberculous mycobacterial infection, for example, are identified. Airway clearance is the mainstay of therapy for patients with symptoms of cough and sputum production. Frequently exacerbating patients may benefit from long term antibiotic or mucoactive therapies. Bronchiectasis is a heterogeneous disease and increasingly precision medicine approaches are advocated to target treatments most appropriately and to limit the emergence of antimicrobial resistance.

Microbiology sampling in non-cystic fibrosis bronchiectasis cases from northern Alberta

Non-cystic fibrosis bronchiectasis (NCFB) is a chronic respiratory disease resulting in chronic cough, thick sputum, and lower airway microbial colonization, akin to patients with cystic fibrosis (CF). NCFB is a common, yet under recognized entity which inflicts significant morbidity and mortality particularly to older individuals, with a rising prevalence in the developed world. Given that sputum cultures are a non-invasive method to characterize the lower airway microbiota in NCFB patients, for which pathogenic organisms are associated with worsened outcomes, we sought to characterize the microbiological pattern and clinical outcomes associated with sputum culture in a cohort of NCFB patients from Western Canada. A total of 20 subjects were prospectively recruited from various bronchiectasis clinics across the Greater Edmonton area. A retrospective chart review and a symptoms questionnaire was performed, gathering information not limited to symptoms, comorbidities, exacerbations, hospitalizations, sputum production, and sputum culture results over the prior 5 years. Subjects reported frequent hospitalization alongside a significant burden of symptoms. A large majority of sputum cultures grew pathogenic organisms such as Haemophilus influenzae and Pseudomonas aeruginosa. We also note the considerable waste and inefficiency associated with sputum cultures, outlining areas for which this important diagnostic modality can be improved. Accurate characterization of the airway microbiota alongside efficient delivery of health services are key to ensuring the proper treatment of individuals with NCFB, given their high disease burden and frequent hospitalization.

Mucosal administration of anti-bacterial antibodies provide long-term cross-protection against Pseudomonas aeruginosa respiratory infection

Bacterial respiratory infections, either acute or chronic, are major threats to human health. Direct mucosal administration, through the airways, of therapeutic antibodies (Abs) offers a tremendous opportunity to benefit patients with respiratory infections. The mode of action of anti-infective Abs relies on pathogen neutralization and crystallizable fragment (Fc)-mediated recruitment of immune effectors to facilitate their elimination. Using a mouse model of acute pneumonia induced by Pseudomonas aeruginosa, we depicted the immunomodulatory mode of action of a neutralizing anti-bacterial Abs. Beyond the rapid and efficient containment of the primary infection, the Abs delivered through the airways harnessed genuine innate and adaptive immune responses to provide long-term protection, preventing secondary bacterial infection. In vitro antigen-presenting cells stimulation assay, as well as in vivo bacterial challenges and serum transfer experiments indicate an essential contribution of immune complexes with the Abs and pathogen in the induction of the sustained and protective anti-bacterial humoral response. Interestingly, the long-lasting response protected partially against secondary infections with heterologous P. aeruginosa strains. Overall, our findings suggest that Abs delivered mucosally promotes bacteria neutralization and provides protection against secondary infection. This opens novel perspectives for the development of anti-infective Abs delivered to the lung mucosa, to treat respiratory infections.

A Double-Blind Randomized Placebo-Controlled Phase 3 Trial of Tobramycin Inhalation Solution in Adults With Bronchiectasis With Pseudomonas aeruginosa Infection

BACKGROUND

Few large-scale studies have demonstrated the efficacy of tobramycin nebulization in bronchiectasis. We evaluated the efficacy and safety of nebulized tobramycin inhalation solution (TIS) in adults with bronchiectasis with Pseudomonas aeruginosa infection.

RESEARCH QUESTION

Can TIS effectively reduce sputum P aeruginosa density and improve the bronchiectasis-specific quality of life in patients with bronchiectasis with P aeruginosa infection?

STUDY DESIGN AND METHODS

This was a phase 3, 16-week, multicenter, randomized, double-blind, placebo-controlled trial. Eligible adults with bronchiectasis were recruited from October 2018 to July 2021. On the basis of usual care, patients nebulized TIS (300 mg/5 mL twice daily) or normal saline (5 mL twice daily) via vibrating-mesh nebulizer. Treatment consisted of two cycles, each consisting of 28 days on-treatment and 28 days off-treatment. The coprimary end points included changes from baseline in P aeruginosa density and Quality-of-Life Bronchiectasis Respiratory Symptoms score on day 29.

RESULTS

The modified intention-to-treat population consisted of 167 patients in the tobramycin group and 172 patients in the placebo group. Compared with placebo, TIS resulted in a significantly greater reduction in P aeruginosa density (adjusted mean difference, 1.74 log₁₀ colony-forming units/g; 95% CI, 1.12-2.35; P < .001) and greater improvement in Quality-of-Life Bronchiectasis Respiratory Symptoms score (adjusted mean difference, 7.91; 95% CI, 5.72-10.11; P < .001) on day 29. Similar findings were observed on day 85. TIS resulted in a significant reduction in 24-h sputum volume and sputum purulence score on days 29, 57, and 85. More patients became culture negative for P aeruginosa in the tobramycin group than in the placebo group on day 29 (29.3% vs 10.6%). The incidence of adverse events and serious adverse events were comparable between the two groups.

INTERPRETATION

TIS is an effective treatment option and has an acceptable safety profile in patients with bronchiectasis with P aeruginosa infection.

TRIAL REGISTRATION

ClinicalTrials.gov; No. NCT03715322; URL: www.

CLINICALTRIALS

gov.

Impact of the SARS-CoV-2 Virus Pandemic on Patients with Bronchiectasis: A Multicenter Study

BACKGROUND

Infection by SARS-CoV-2 has unquestionably had an impact on the health of patients with chronic respiratory airway diseases, such as COPD and asthma, but little information is available about its impact on patients with bronchiectasis. The objective of the present study was to analyze the effect of the SARS-CoV-2 pandemic on the state of health, characteristics, and clinical severity (including the number and severity of exacerbations) of patients with non-cystic fibrosis bronchiectasis.

METHODS

This study was multicenter, observational, and ambispective (with data collected before and during the SARS-CoV-2 pandemic), and included 150 patients diagnosed with non-cystic fibrosis bronchiectasis.

RESULTS

A significant drop was observed in the number and severity of the exacerbations (57% in all exacerbations and 50% in severe exacerbations) in the E-FACED and BSI multidimensional scores, in the pandemic, compared with the pre-pandemic period. There was also a drop in the percentage of sputum samples positive for pathogenic microorganisms in general (from 58% to 44.7%) and, more specifically, Pseudomonas aeruginosa (from 23.3% to 13.3%) and Haemophilus influenzae (from 21.3% to 14%).

CONCLUSIONS

During the SARS-CoV-2 period, a significant reduction was observed in the exacerbations, severity, and isolations of pathogenic microorganisms in patients with bronchiectasis.

Multidrug-resistant Pseudomonas aeruginosa is predisposed to lasR mutation through up-regulated activity of efflux pumps in non-cystic fibrosis bronchiectasis patients

Background

Multidrug-resistant (MDR) Pseudomonas aeruginosa is a frequent opportunistic pathogen that causes significant mortality in patients with non-cystic fibrosis bronchiectasis (NCFB). Although the quorum sensing (QS) system is a potential target for treatment, lasR mutants that present with a QS-deficient phenotype have been frequently reported among clinical P. aeruginosa isolates. We aimed to investigate whether antibiotic resistance would select for lasR mutants during chronic P. aeruginosa lung infection and determine the mechanism underlying the phenomenon.

Methods

We prospectively evaluated episodes of chronic P. aeruginosa lung infections in NCFB patients over a 2-year period at two centers of our institution. QS phenotypic assessments and whole-genome sequencing (WGS) of P. aeruginosa isolates were performed. Evolution experiments were conducted to confirm the emergence of lasR mutants in clinical MDR P. aeruginosa cultures.

Results

We analyzed episodes of P. aeruginosa infection among 97 NCFB patients and found only prior carbapenem exposure independently predictive of the isolation of MDR P. aeruginosa strains. Compared with non-MDR isolates, MDR isolates presented significantly QS-deficient phenotypes, which could not be complemented by the exogenous addition of 3OC12-HSL. The paired isolates showed that their QS-phenotype deficiency occurred after MDR was developed. Whole-genome sequencing analysis revealed that lasR nonsynonymous mutations were significantly more frequent in MDR isolates, and positive correlations of mutation frequencies were observed between genes of lasR and negative-efflux-pump regulators (nalC and mexZ). The addition of the efflux pump inhibitor PAβN could not only promote QS phenotypes of these MDR isolates but also delay the early emergence of lasR mutants in evolution experiments.

Conclusions

Our data indicated that MDR P. aeruginosa was predisposed to lasR mutation through the upregulated activity of efflux pumps. These findings suggest that anti-QS therapy combined with efflux pump inhibitors might be a potential strategy for NCFB patients in the challenge of MDR P. aeruginosa infections.

Poly (acetyl, arginyl) glucosamine disrupts Pseudomonas aeruginosa biofilms and enhances bacterial clearance in a rat lung infection model

Pseudomonas aeruginosa is a common opportunistic pathogen that can cause chronic infections in multiple disease states, including respiratory infections in patients with cystic fibrosis (CF) and non-CF bronchiectasis. Like many opportunists, P. aeruginosa forms multicellular biofilm communities that are widely thought to be an important determinant of bacterial persistence and resistance to antimicrobials and host immune effectors during chronic/recurrent infections. Poly (acetyl, arginyl) glucosamine (PAAG) is a glycopolymer that has antimicrobial activity against a broad range of bacterial species, and also has mucolytic activity, which can normalize the rheological properties of cystic fibrosis mucus. In this study, we sought to evaluate the effect of PAAG on P. aeruginosa bacteria within biofilms in vitro, and in the context of experimental pulmonary infection in a rodent infection model. PAAG treatment caused significant bactericidal activity against P. aeruginosa biofilms, and a reduction in the total biomass of preformed P. aeruginosa biofilms on abiotic surfaces, as well as on the surface of immortalized cystic fibrosis human bronchial epithelial cells. Studies of membrane integrity indicated that PAAG causes changes to P. aeruginosa cell morphology and dysregulates membrane polarity. PAAG treatment reduced infection and consequent tissue inflammation in experimental P. aeruginosa rat infections. Based on these findings we conclude that PAAG represents a novel means to combat P. aeruginosa infection, and may warrant further evaluation as a therapeutic.

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).

Exacerbation of bronchiectasis by Pseudomonas putida complicating COVID-19 disease: A case report

Novel coronavirus infection presents with greater severity in individuals with comorbid chronic lung diseases. Bronchiectasis is an illness characterized by permanent enlargement of the airways, presenting with chronic cough and sputum production and vulnerability to lung infections. Bronchiectasis is not a common comorbid disease in patients with COVID-19 disease and bronchiectasis exacerbation rates were decreased during the pandemic. However, COVID-19 disease is associated with worse outcomes in patients with bronchiectasis and patients with bronchiectasis are more susceptible to SARS-CoV-2 infection development. Pseudomonas putida is an opportunistic pathogen, causing infections mostly in immunocompromised hosts and is not a frequent bacterial colonizer in patients with bronchiectasis. This present study reports a rare case of exacerbation of bronchiectasis by Pseudomonas putida complicating COVID-19 disease in an immunocompetent 70-year-old woman. Clinicians should be aware that SARS-CoV-2 infection is probably a precipitating factor of bronchiectasis exacerbation while bronchiectasis is a risk factor for greater severity of SARS-CoV-2 infection.

Divergent synthesis and biological evaluation of 2-(trifluoromethyl)pyridines as virulence-attenuating inverse agonists targeting PqsR

A short and divergent route towards new derivatives of 2-(trifluoromethyl)pyridines as potent inverse agonists of the bacterial target PqsR against Pseudomonas aeruginosa (PA) infections is described. This Gram-negative pathogen causes severe nosocomial infections and common antibiotic treatment options are rendered ineffective due to resistance issues. Based on an earlier identified optimized hit, we conducted derivatization and rigidification attempts employing two central building blocks. The western part of the molecule is built up via a 2-(trifluoromethyl)pyridine head group equipped with a terminal alkyne. The eastern section is then introduced through aryliode motifs exploiting Sonogashira as well as Suzuki-type chemistry. Subsequent modification provided quick access to an array of compounds, allowed for deep SAR insights, and enabled to optimize the hit scaffold into a lead structure of nanomolar potency combined with favorable in vitro ADME/T features.

Pseudomonas aeruginosa in Bronchiectasis

Pseudomonas aeruginosa (PA) in patients with bronchiectasis (BE) is associated with a poor outcome and quality of life, and its presence is considered a marker of disease severity. This opportunistic pathogen is known for its ability to produce biofilms on biotic or abiotic surfaces and to survive environmental stress exerted by antimicrobials, inflammation, and nutrient or oxygen depletion. The presence of PA biofilms has been linked to chronic respiratory infection in cystic fibrosis but not in BE. There is considerable inconsistency in the reported infection/eradication rates of PA and chronic PA. In addition, inadequate antimicrobial treatment may potentiate the progression from intermittent to chronic infection and also the emergence of antibiotic resistance. A better comprehension of the pathophysiology of PA infections and its implications for BE is urgently needed. This can drive improvements in diagnostic accuracy, can move us toward a new consensus definition of chronic infection, can better define the follow-up of patients at risk of PA, and can achieve more successful eradication rates. In addition, the new technological advances regarding molecular diagnostics, -omics, and biomarkers require us to reconsider our traditional concepts.

Clinical and Radiological Phenotypes and Endotypes

Bronchiectasis is a heterogenous disease with multiple etiologies and associated comorbidities. As bronchiectasis is a complex disease, it is unsound to think of it as a single disease particularly when the differing etiologies are likely to be driving bronchiectasis through initial divergent molecular pathways, known as endotypes, that phenotypically present as the same disease due to protracted airway inflammation, but revealing potential differing underlying mechanisms that may have disparity of drug responses. Improved understanding of the cellular immune, inflammatory, and microbiological milieu associated with clinical and radiological features of bronchiectasis has resulted in the recognition of important endotypes and phenotypes that will allow for personalized treatments to improve quality of life and outcomes of patients with bronchiectasis. Here we discuss clinical and radiological phenotypes, as well as emerging molecular endotypes that are possible treatable traits in bronchiectasis.

In Vitro Activity of the Ultrabroad-Spectrum Beta-Lactamase Inhibitor QPX7728 in Combination with Multiple Beta-Lactam Antibiotics against Pseudomonas aeruginosa

QPX7728 is an ultrabroad-spectrum beta-lactamase inhibitor with potent inhibition of key serine and metallo beta-lactamases. QPX7728 enhances the potency of multiple beta-lactams in beta-lactamase-producing Enterobacterales and Acinetobacter spp. In this study, we evaluated the in vitro activity of QPX7728 (QPX; 8 μg/ml) combined with multiple beta-lactams against clinical isolates of Pseudomonas aeruginosa with various beta-lactam resistance mechanisms. Seven hundred ninety clinical isolates were included in this study; 500 isolates, termed a “representative panel,” were selected to be representative of the MIC distribution of meropenem (MEM), ceftazidime-avibactam (CAZ-AVI), and ceftolozane-tazobactam (TOL-TAZ) resistance for clinical isolates according to 2017 SENTRY surveillance data. An additional 290 selected isolates (“challenge panel”) that were either nonsusceptible to MEM or were resistant to TOL-TAZ or CAZ-AVI were also tested; 61 strains carried metallo-beta-lactamases (MBLs), 211 strains were defective in the carbapenem porin OprD, and 185 strains had the MexAB-OprM efflux pump overproduced based on a phenotypic test. Against the representative panel, susceptibility for all QPX7728/beta-lactam combinations was >90%. For the challenge panel, QPX-ceftolozane (TOL) was the most active combination (78.6% susceptible) followed by equipotent QPX-piperacillin (PIP) and QPX-cefepime (FEP), restoring susceptibility in 70.3% of strains (CLSI breakpoints for the beta-lactam compound alone). For MBL-negative strains, QPX-TOL and QPX-FEP restored the MIC values to susceptibility rates in ∼90% and ∼80% of strains, respectively, versus 68% to 70% for QPX-MEM and QPX-PIP and 63% to 65% for TOL-TAZ and CAZ-AVI, respectively. For MBL-positive strains, QPX-PIP restored the MIC to susceptibility values for ∼70% of strains versus 2% to 40% for other combinations. Increased efflux and impaired OprD had various effect on QPX7728 combination depending on the partner beta-lactam tested. QPX7728 enhanced the potency of multiple beta-lactams against P. aeruginosa, with varied results according to beta-lactamase production and other intrinsic resistance mechanisms.

Personalized approaches to bronchiectasis

Introduction: Interest in bronchiectasis is increasing due to its rising prevalence, associated with aging populations and the extended use of high-resolution chest tomography (HRCT), and the resulting high morbidity, mortality, and demand for resources.Areas covered: This article provides an extensive review of bronchiectasis as a complex and heterogeneous disease, as well as examining the difficulty of establishing useful clinical phenotypes. In keeping with the aims of 'precision medicine', we address the disease of bronchiectasis from three specific perspectives: severity, activity, and impact. We used PubMed to search the literature for articles including the following keywords: personalized medicine, bronchiectasis, biomarkers, phenotypes, precision medicine, treatable traits. We reviewed the most relevant articles published over the last 5 years.Expert opinion: This article reflects on the usefulness of these three dimensions in 'control panels' and clinical fingerprinting, as well as approaches to personalized medicine and the treatable features of bronchiectasis non-cystic fibrosis.

A Potential Quorum-Sensing Inhibitor for Bronchiectasis Therapy: Quercetin-Chitosan Nanoparticle Complex Exhibiting Superior Inhibition of Biofilm Formation and Swimming Motility of Pseudomonas aeruginosa to the Native Quercetin

Quercetin (QUE)—a plant-derived flavonoid, is recently established as an effective quorum sensing (QS) inhibiting agent in Pseudomonas aeruginosa—the main bacterial pathogen in bronchiectasis lungs. Successful clinical application of QUE, however, is hindered by its low solubility in physiological fluids. Herein we developed a solubility enhancement strategy of QUE in the form of a stable amorphous nanoparticle complex (nanoplex) of QUE and chitosan (CHI), which was prepared by electrostatically driven complexation between ionized QUE molecules and oppositely charged CHI. At its optimal preparation condition, the QUE–CHI nanoplex exhibited a size of roughly 150 nm with a 25% QUE payload and 60% complexation efficiency. The complexation with CHI had no adverse effect on the antibacterial and anticancer activities of QUE, signifying the preservation of QUE’s bioactivities in the nanoplex. Compared to the native QUE, the QUE–CHI nanoplex exhibited superior QS inhibition in suppressing the QS-regulated swimming motility and biofilm formation of P. aeruginosa, but not in suppressing the virulence factor production. The superior inhibitions of the biofilm formation and swimming motility afforded by the nanoplex were attributed to (1) its higher kinetic solubility (5-times higher) that led to higher QUE exposures, and (2) the synergistic QS inhibition attributed to its CHI fraction.

Pseudomonas aeruginosa associated with severity of non-cystic fibrosis bronchiectasis measured by the modified bronchiectasis severity score (BSI) and the FACED: The US bronchiectasis and NTM Research Registry (BRR) study

RATIONALE

Non-cystic fibrosis bronchiectasis (NCFB) is characterized by dilated bronchi, poor mucus clearance and susceptibility to bacterial infection. Pseudomonas aeruginosa (PA) is one of the most frequently isolated pathogens in patients with NCFB. The purpose of this study was to evaluate the association between presence of PA and disease severity in patients within the US Bronchiectasis and Nontuberculous mycobacteria (NTM) Research Registry (BRR).

METHODS

Baseline US BRR data from adult patients with NCFB collected between 2008 and 2018 was used for this study. The presence of PA was defined as one or more positive PA cultures within two years prior to enrollment. Modified Bronchiectasis Severity Index (m-BSI) and modified FACED (m-FACED) were computed to evaluate severity of bronchiectasis. Unadjusted and multivariable multinomial regression models were used to assess the association between presence of PA and severity of bronchiectasis.

RESULTS

Average age of the study participants (n = 1831) was 63.7 years (SD = 14.1), 91.5% white, and 78.8% female. Presence of PA was identified in 25.4% of the patients. Patients with presence of PA had significantly lower mean pre-bronchodilator FEV1% predicted compared to those without PA (62.8% vs. 73.7%, p < .0001). In multivariate analyses, patients with presence of PA had significantly greater odds for having high (ORadj = 6.15 (95%CI:3.98-9.50) and intermediate (ORadj = 2.06 (95%CI:1.37-3.09) severity vs. low severity on m-BSI.

CONCLUSION

The presence of PA is common in patients with NCFB within the Bronchiectasis and NTM Research Registry. Severity of bronchiectasis is significantly greater in patients with PA which emphasizes high burden of the disease.

Investigation and Functional Enrichment Analysis of the Human Host Interaction Network with Common Gram-Negative Respiratory Pathogens Predicts Possible Association with Lung Adenocarcinoma

Haemophilus influenzae (Hi), Moraxella catarrhalis (MorCa) and Pseudomonas aeruginosa (Psa) are three of the most common gram-negative bacteria responsible for human respiratory diseases. In this study, we aimed to identify, using the functional enrichment analysis (FEA), the human gene interaction network with the aforementioned bacteria in order to elucidate the full spectrum of induced pathogenicity. The Human Pathogen Interaction Database (HPIDB 3.0) was used to identify the human proteins that interact with the three pathogens. FEA was performed via the ToppFun tool of the ToppGene Suite and the GeneCodis database so as to identify enriched gene ontologies (GO) of biological processes (BP), cellular components (CC) and diseases. In total, 11 human proteins were found to interact with the bacterial pathogens. FEA of BP GOs revealed associations with mitochondrial membrane permeability relative to apoptotic pathways. FEA of CC GOs revealed associations with focal adhesion, cell junctions and exosomes. The most significantly enriched annotations in diseases and pathways were lung adenocarcinoma and cell cycle, respectively. Our results suggest that the Hi, MorCa and Psa pathogens could be related to the pathogenesis and/or progression of lung adenocarcinoma via the targeting of the epithelial cellular junctions and the subsequent deregulation of the cell adhesion and apoptotic pathways. These hypotheses should be experimentally validated.

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.

Neutrophils to Lymphocyte Ratio as a Biomarker in Bronchiectasis Exacerbation: A Retrospective Study

Introduction

Bronchiectasis is a disorder resulting mainly from bronchial inflammation caused by recurrent or chronic infections. It is characterized by permanently dilated airways due to bronchial wall destruction. Exacerbations have a key role in bronchiectasis as they are associated with a negative impact on patient prognosis. Exacerbations are generally infectious events caused mostly by bacterial microorganisms. Infective or inflammatory agents cause neutrophil recruitment into the airways, which leads to proteolytic enzymes such as neutrophil elastase and matrix metalloproteinases release, resulting in airway matrix destruction. Neutrophil to lymphocyte ratio (NLR) is used as a biomarker of inflammation. It is calculated by dividing the number of neutrophils by the number of lymphocytes. Our aim is to evaluate Neutrophils to Lymphocyte Ratio in patients with bronchiectasis exacerbation and its correlation to microbiological data.

Methods 

The study involved patients with a diagnosis of bronchiectasis based on high-resolution computerised tomography (HRCT) of the chest who fulfilled the criteria of bronchiectasis exacerbation. Complete blood counts with differential counts, which included total white blood cells, neutrophils and lymphocytes, were obtained. NLR and C-reactive protein (CRP) levels were measured in patients with bronchiectasis exacerbation and in healthy controls. NLR was calculated as the ratio of the neutrophils to lymphocytes. The mean NLR values in patients with bronchiectasis exacerbation were compared to mean NLR values in healthy controls. The NLR values were compared to CRP levels in patients with bronchiectasis exacerbation. Sputum cultures were performed in all patients. The mean NLR values in patients with positive sputum cultures were compared with mean NLR values in patients with negative sputum cultures, and mean NLR values in patients with isolated Pseudomonas aeruginosa in sputum cultures were compared to mean NLR values in patients with other infectious agents isolated.

Results

The study population consisted of 80 patients with bronchiectasis exacerbation - 54 males and 26 females - with a mean age of 77.3±8.4 years, and 64 healthy controls - 36 males and 28 females - with a mean age of 62.9±15.3 years. The mean CRP levels in patients with bronchiectasis exacerbation were 75.03±73.87 mg/l. The mean NLR value in patients with bronchiectasis exacerbation was 9.2±7.8 and the mean NLR value of controls was 3.1±2.9 (p<0.001). The NLR values in patients with bronchiectasis exacerbation had no linear correlation with CRP values in these patients (r=0.002, p=0.992). Fifty-two patients had positive sputum cultures and 28 patients had negative sputum cultures. The mean NLR value in patients with positive sputum cultures was 10.5±9.1, and in patients with negative sputum cultures, it was 6.7±3.6 (p<0.012). The mean NLR value in patients with P.aeruginosa was 10.1±9.5, and in patients with other microorganisms isolated, it was 10.8±8.9 (p=0.784).

Conclusions

Neutrophil to lymphocyte ratio values are statistically greater in patients with bronchiectasis exacerbation compared to healthy controls. There is no linear correlation between NLR and CRP in these patients. NLR values are statistically greater in patients with positive sputum cultures compared to those with negative sputum cultures. Therefore, NLR can be used for predicting positive cultures in patients with bronchiectasis exacerbation.

The ThiL enzyme is a valid antibacterial target essential for both thiamine biosynthesis and salvage pathways in Pseudomonas aeruginosa

Thiamine pyrophosphate (TPP) is an essential cofactor for various pivotal cellular processes in all living organisms, including bacteria. Thiamine biosynthesis occurs in bacteria but not in humans; therefore, the enzymes in this pathway are attractive targets for antibiotic development. Among these enzymes, thiamine monophosphate kinase (ThiL) catalyzes the final step of this pathway, phosphorylating thiamine monophosphate to produce TPP. Here, we extensively investigated ThiL in Pseudomonas aeruginosa, a major pathogen responsible for hospital-acquired infections. We demonstrate that thiL deletion abolishes not only thiamine biosynthesis but also thiamine salvage capability and results in growth defects of the ΔthiL strain even in the presence of thiamine derivatives, except for TPP. Most importantly, the pathogenesis of the ΔthiL strain was markedly attenuated, compared with that of WT cells, with lower inflammatory cytokine induction and 10³-10⁴-fold decreased bacterial loads in an in vivo infection model in which the intracellular TPP level was in the submicromolar range. To validate P. aeruginosa ThiL (PaThiL) as a drug target, we further characterized its biochemical properties, determining a V _max of 4.0 ± 0.2 nmol·min^-1 and K_m values of 111 ± 8 and 8.0 ± 3.5 μm for ATP and thiamine monophosphate, respectively. An in vitro small-molecule screening assay identified PaThiL inhibitors including WAY213613, a noncompetitive inhibitor with a K_i value of 13.4 ± 2.3 μm and potential antibacterial activity against P. aeruginosa These comprehensive biological and biochemical results indicate that PaThiL represents a potential drug target for the development of an augmented repertoire of antibiotics against P. aeruginosa.

Ternary nanoparticle complex of antibiotic, polyelectrolyte, and mucolytic enzyme as a potential antibiotic delivery system in bronchiectasis therapy

Antibiotic-polyelectrolyte nanoparticle complex (or nanoplex in short) has been recently demonstrated as a superior antibiotic delivery system to the native antibiotic in bronchiectasis therapy owed to its ability to overcome the lung's mucus barrier and generate high localized antibiotic exposure in the infected sites. The present work aimed to further improve the mucus permeability, hence the antibacterial efficacy of the nanoplex, by incorporating mucolytic enzyme papain (PAP) at the nanoplex formation step to produce PAP-decorated antibiotic-polyelectrolyte nanoplex exhibiting built-in mucolytic capability. Ciprofloxacin (CIP) and dextran sulfate (DXT) were used as the models for antibiotics and polyelectrolyte, respectively. The results showed that the PAP inclusion had minimal effects on the physical characteristics, preparation efficiency, and dissolution of the CIP-DXT nanoplex. The optimal CIP-(DXT-PAP) nanoplex exhibited size and zeta potential of approximately 200 nm and -50 mV with CIP and PAP payloads of 60% and 32% (w/w), respectively. The nanoplex was prepared at high efficiency with larger than 80% CIP and PAP utilization rates. The CIP-(DXT-PAP) nanoplex exhibited tenfold improvement in the mucus permeability compared to its CIP-DXT nanoplex counterpart, resulting in the former's superior bactericidal activity against clinical Pseudomonas aeruginosa biofilm in the presence of mucus barrier. A trade-off, nevertheless, existed between antibacterial efficacy and cytotoxicity towards human lung epithelium cells upon the incorporation of PAP above a certain concentration threshold. Therefore, the optimal dosing of the CIP-(DXT-PAP) nanoplex must be carefully determined.

Noncystic fibrosis bronchiectasis management: opportunities and challenges

PURPOSE OF REVIEW

Noncystic fibrosis bronchiectasis is a challenging disease which carries a heavy healthcare burden and significant mortality and morbidity. This review highlights the challenges in the diagnosis of bronchiectasis and discusses the management strategies and research opportunities in this field.

RECENT FINDINGS

The challenges in the management of bronchiectasis appear to be multifactorial, arising from both etiological heterogeneity and disease-specific management. Frequent inflammation and infections not only lead to progressive respiratory failure but also increase the risk of cardiovascular complications. No therapies are approved specifically for adult bronchiectasis, but new guidelines and recent studies outline strategies for control of infection and inflammation and for prevention of frequent exacerbations to improve overall prognosis.

SUMMARY

Recent studies in the management of bronchiectasis are encouraging. Advances have been made in understanding both disease heterogeneity and best practices for care; interventions such as daily mucociliary clearance, eradication of colonized microbial organisms, and control of inflammation may result in favorable outcomes.

Hot topics and current controversies in non-cystic fibrosis bronchiectasis

Non-cystic fibrosis bronchiectasis (NCFB) is a neglected and orphan disease with poor advances through the 20th century. However, its prevalence is rising and with this come new challenges for physicians. Few guidelines are available to guide clinicians on how to diagnose and manage patients with NCFB. Many areas of debate persist, and there is lack of consensus about research priorities most needed to advance patient care and improve clinical outcomes. In this review, we highlight the current hot topics in NCFB and present updated evidence to inform the critical areas of controversy.

Non-cystic fibrosis bronchiectasis (NCFB) is a neglected and orphan disease with poor advances through the 20th century. Physicians should understand available data to provide evidence-based treatments to patients suffering from NCFB.http://bit.ly/2kBGVsx

Efficacy and safety of tobramycin inhalation powder in bronchiectasis patients with P. aeruginosa infection: Design of a dose-finding study (iBEST-1)

In patients with bronchiectasis (BE), infection with Pseudomonas aeruginosa (Pa) results in disease progression, frequent pulmonary exacerbations and lung function decline. However, at present, no inhaled antibiotics have been approved for the treatment of these patients. Tobramycin inhalation powder (TIP), approved for treatment of Pa infection in cystic fibrosis, could be a promising candidate. We aimed to assess effective and well-tolerated doses and regimens of TIP in BE patients with Pa infection. In this phase II, double-blind, placebo-controlled, randomised study, three different daily doses of TIP are administered either as continuous or cyclical regimens. The study protocol comprises 7-28 days of screening, 112 days of double-blind treatment and 56 days of follow-up. The plan was to enrol 180 patients (aged ≥18 years) with BE, documented Pa infection and a history of exacerbations. The primary outcome is change in sputum Pa density from baseline. Key secondary outcomes include number of pulmonary exacerbations, use of antipseudomonal antibiotics, serum and sputum tobramycin concentrations, quality of life and safety. Exploratory endpoints include lung clearance index, sputum inflammatory markers and microbiome analysis. As of October 2018, 107/180 patients were enrolled at 34 sites (six countries) following which recruitment was closed for administrative reasons unrelated to safety findings. Despite a reduced sample size from initially planned enrolment, the unique design may inform the benefit-risk profile of TIP in BE patients with chronic Pa infection. Moreover, several novel and exploratory endpoints (lung clearance index, inflammatory biomarkers, lung microbiome), will contribute to the advancement of research in this area.

Elucidation of the pharmacokinetic/pharmacodynamic determinants of fosfomycin activity against Pseudomonas aeruginosa using a dynamic in vitro model

Objectives

To identify the fosfomycin pharmacokinetic (PK)/pharmacodynamic (PD) index (fT>MIC, fAUC/MIC or fCmax/MIC) most closely correlated with activity against Pseudomonas aeruginosa and determine the PK/PD target associated with various extents of bacterial killing and the prevention of emergence of resistance.

Methods

Dose fractionation was conducted over 24 h in a dynamic one-compartment in vitro PK/PD model utilizing P. aeruginosa ATCC 27853 and two MDR clinical isolates (CR 1005 and CW 7). In total, 35 different dosing regimens were examined across the three strains. Microbiological response was examined by log changes and population analysis profiles. A Hill-type Emax model was fitted to the killing effect data (expressed as the log10 ratio of the area under the cfu/mL curve for treated regimens versus controls).

Results

Bacterial killing of no more than ∼3 log10 cfu/mL was achieved irrespective of regimen. The fAUC/MIC was the PK/PD index most closely correlated with efficacy (R2 = 0.80). The fAUC/MIC targets required to achieve 1 and 2 log10 reductions in the area under the cfu/mL curve relative to growth control were 489 and 1024, respectively. No regimen was able to suppress the emergence of resistance, and near-complete replacement of susceptible with resistant subpopulations occurred with virtually all regimens.

Conclusions

Bacterial killing for fosfomycin against P. aeruginosa was most closely associated with the fAUC/MIC. Suppression of fosfomycin-resistant subpopulations could not be achieved even with fosfomycin exposures well above those that can be safely achieved clinically.

Emerging therapies against infections with Pseudomonas aeruginosa

Infections with Pseudomonas aeruginosa have been marked with the highest priority for surveillance and epidemiological research on the basis of parameters such as incidence, case fatality rates, chronicity of illness, available options for prevention and treatment, health-care utilization, and societal impact. P. aeruginosa is one of the six ESKAPE pathogens that are the major cause of nosocomial infections and are a global threat because of their capacity to become increasingly resistant to all available antibiotics. This review reports on current pre-clinical and clinical advances of anti-pseudomonal therapies in the fields of drug development, antimicrobial chemotherapy, vaccines, phage therapy, non-bactericidal pathoblockers, outer membrane sensitizers, and host defense reinforcement.

Management of bronchiectasis in adults

Once neglected in research and underappreciated in practice, there is renewed interest in bronchiectasis unrelated to cystic fibrosis. Bronchiectasis is a chronic lung disease characterised by chronic cough, sputum production and recurrent pulmonary exacerbations. It is diagnosed radiologically on high resolution computed tomography chest scan by bronchial dilatation (wider than the accompanying artery). The causes of bronchiectasis are diverse and include previous respiratory tract infections, chronic obstructive pulmonary disease, asthma, immunodeficiency and connective tissue diseases. A large proportion of cases are idiopathic, reflecting our incomplete understanding of disease pathogenesis. Progress in the evidence base is reflected in the 2017 European management guidelines and the 2015 update to the Australian guidelines. Effective airway clearance remains the cornerstone of bronchiectasis management. This should be personalised and reviewed regularly by a respiratory physiotherapist. There is now robust evidence for the long term use of oral macrolide antibiotics in selected patients to reduce exacerbation frequency. The routine use of long term inhaled corticosteroids and/or long-acting bronchodilators should be avoided, unless concomitant chronic obstructive pulmonary disease or asthma exists. The evidence for nebulised agents including hypertonic saline, mannitol and antibiotics is evolving; however, access is challenging outside tertiary clinics, and nebulising equipment is required. Smokers should be supported to quit. All patients should receive influenza and pneumococcal vaccination. Patients with impaired exercise capacity should attend pulmonary rehabilitation. There is an important minority of patients for whom aetiology-specific treatment exists. The prevalence of bronchiectasis is increasing worldwide; however, the burden of disease within Australia is not well defined. To this end, the Australian Bronchiectasis Registry began recruitment in 2016 and is interoperable with the European and United States bronchiectasis registries to enable collaborative research. The recent addition of a bronchiectasis diagnosis-related group to the Australian Refined Diagnostic Related Group classification system will allow definition of the disease burden within the Australian hospital system.

Bronchiectasis: A Complex, Heterogeneous Disease

Most areas of respiratory medicine continue to use an Oslerian approach, based on signs and symptoms, in which the disease is the center of all activity. However, this paradigm is changing. Now that lung diseases have been recognized as heterogeneous and complex, we are moving towards more personalized, precise, patient-oriented medicine. The aim of this review was to define the current state of the knowledge on bronchiectasis, or, more accurately, the bronchiectasis syndrome, as a multidimensional, systemic, heterogeneous, complex disease. We explore the advances that have already been made, and above all the many steps that are still to be taken. We also propose some tools which might facilitate the application of these concepts in clinical practice, and help us continue our journey towards a more holistic view of this disease.

An evaluation of inhaled antibiotic liposome versus antibiotic nanoplex in controlling infection in bronchiectasis

Inhaled antibiotic nanoparticles have emerged as an effective strategy to control infection in bronchiectasis lung owed to their mucus-penetrating ability. Using ciprofloxacin (CIP) as the model antibiotic, we evaluated dry powder inhaler (DPI) formulations of two classes of antibiotic nanoparticles (i.e. liposome and nanoplex) in their (1) physical characteristics (i.e. size, zeta potential, CIP payload, preparation efficiency), (2) dissolution in artificial sputum medium, (3) ex vivo mucus permeability, (4) antimicrobial activity against Pseudomonas aeruginosa in mucus, (5) cytotoxicity towards human lung epithelium cells, and (6) in vitro aerosolization efficiency. The results showed that the CIP nanoplex exhibited fast dissolution with CIP supersaturation generation, in contrast to the slower release of the liposome (80 versus 30% dissolution after 1 h). Both nanoparticles readily overcame the mucus barrier attributed to their nanosize and mucus-inert surface (50% permeation after 1 h), leading to their similarly high antipseudomonal activity. The CIP liposome, however, possessed much lower CIP payload than the nanoplex (84% versus 3.5%), resulting in high lipid contents in its DPI formulation that led to higher cytotoxicity and lower aerosolization efficiency. The CIP nanoplex thus represented a superior formulation owed to its simpler preparation, higher CIP payload hence lower dosage, better aerosolization, and lower cytotoxicity.

Novel Inhalable Ciprofloxacin Dry Powders for Bronchiectasis Therapy: Mannitol-Silk Fibroin Binary Microparticles with High-Payload and Improved Aerosolized Properties

Non-cystic fibrosis bronchiectasis (NCFB) is a chronic respiratory disease associated with the high morbidity and mortality. Long-term intermittent therapy by inhalable antibiotics has recently emerged as an effective approach for NCFB treatment. However, the effective delivery of antibiotics to the lung requires administering a high dose to the site of infection. Herein, we investigated the novel inhalable silk-based microparticles as a promising approach to deliver high-payload ciprofloxacin (CIP) for NCFB therapy. Silk fibroin (SF) was applied to improve drug-payload and deposit efficiency of the dry powder particles. Mannitol was added as a mucokinetic agent. The dry powder inhaler (DPI) formulations of CIP microparticles were evaluated in vitro in terms of the aerodynamic performance, particle size distribution, drug loading, morphology, and their solid state. The optimal formulation (highest drug loading, 80%) exhibited superior aerosolization performance in terms of fine particle fraction (45.04 ± 0.84%), emitted dose (98.10 ± 1.27%), mass median aerodynamic diameter (3.75 ± 0.03 μm), and geometric standard deviation (1.66 ± 0.10). The improved drug loading was due to the electrostatic interactions between the SF and CIP by adsorption, and the superior aerosolization efficiency would be largely attributed to the fluffy and porous cotton-like property and low-density structure of SF. The presented results indicated the novel inhalable silk-based DPI microparticles of CIP could provide a promising strategy for the treatment of NCFB.

Paediatric and adult bronchiectasis: Monitoring, cross-infection, role of multidisciplinary teams and self-management plans

Bronchiectasis is a chronic lung disease associated with structurally abnormal bronchi, clinically manifested by a persistent wet/productive cough, airway infections and recurrent exacerbations. Early identification and treatment of acute exacerbations is an integral part of monitoring and annual review, in both adults and children, to minimize further damage due to infection and inflammation. Common modalities used to monitor disease progression include clinical signs and symptoms, frequency of exacerbations and/or number of hospital admissions, lung function (forced expiratory volume in 1 s (FEV₁ )% predicted), imaging (radiological severity of disease) and sputum microbiology (chronic infection with Pseudomonas aeruginosa). There is good evidence that these monitoring tools can be used to accurately assess severity of disease and predict prognosis in terms of mortality and future hospitalization. Other tools that are currently used in research settings such as health-related quality of life (QoL) questionnaires, magnetic resonance imaging and lung clearance index can be burdensome and require additional expertise or resource, which limits their use in clinical practice. Studies have demonstrated that cross-infection, especially with P. aeruginosa between patients with bronchiectasis is possible but infrequent. This should not limit participation of patients in group activities such as pulmonary rehabilitation, and simple infection control measures should be carried out to limit the risk of cross-transmission. A multidisciplinary approach to care which includes respiratory physicians, chest physiotherapists, nurse specialists and other allied health professionals are vital in providing holistic care. Patient education and personalized self-management plans are also important despite limited evidence it improves QoL or frequency of exacerbations.

Bronchiectasis: Treatment decisions for pulmonary exacerbations and their prevention

Interest in bronchiectasis has increased over the past two decades, as shown by the establishment of disease-specific registries in several countries, the publication of management guidelines and a growing number of clinical trials to address evidence gaps for treatment decisions. This review considers the evidence for defining and treating pulmonary exacerbations, the approaches for eradication of newly identified airway pathogens and the methods to prevent exacerbations through long-term treatments from a pragmatic practice-based perspective. Areas for future studies are also explored. Watch the video abstract.

Altered community compositions of Proteobacteria in adults with bronchiectasis

Background

Bronchiectasis is a debilitating disease with chronic airway infection. Proteobacteria, the dominant phylum, can be detected with high-throughput sequencing.

Objective

To stratify Proteobacteria compositions according to culture findings in bronchiectasis.

Patients and methods

We sampled sputum, split for culture and 16srRNA sequencing, from 106 patients with stable bronchiectasis and 17 healthy subjects. Paired sputa from 22 bronchiectasis patients were collected during exacerbations and convalescence.

Results

Forty-five, 41, and 20 patients with clinically stable bronchiectasis had isolated Pseudomonas aeruginosa (PA), other potentially pathogenic microorganisms, and commensals at the initial visit, respectively. The PA group (but not other groups) demonstrated significantly greater relative abundance of Proteobacteria, and lower Shannon–Wiener Diversity Index, Simpson Diversity Index, and richness compared with healthy subjects. Pseudomonas was the dominant genus that discriminated bronchiectasis patients (particularly in the PA group) from healthy subjects. Compared with baseline levels, Proteobacteria community compositions in the PA group, but not in other groups, were more resilient during exacerbations and convalescence.

Conclusion

Proteobacteria community compositions could be partially reflected by conventional sputum bacterial culture. Significantly altered Proteobacteria community compositions – particularly, the increased relative abundance of Pseudomonas and diminished community diversity – represent critical targets for novel interventions to restore normal airway microen-vironment in patients with bronchiectasis.

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.

Current and future pharmacotherapy options for non-cystic fibrosis bronchiectasis

INTRODUCTION

In recent years, there has been an increasing number of clinical trials investigating the effect of pharmacological treatments on patients with bronchiectasis. Areas covered: This review provides an overview of current drugs used in bronchiectasis patients as well as those that could make a future contribution to the management of this disease. Expert commentary: Bronchiectasis is a very heterogeneous disease, so it can be studied from a phenotypic standpoint and its pathophysiological mechanisms (endotypes) can be defined. This provides an interesting field of research as it enables the identification of patients suitable for inclusion in specific clinical trials on new drugs.

A new therapeutic avenue for bronchiectasis: Dry powder inhaler of ciprofloxacin nanoplex exhibits superior ex vivo mucus permeability and antibacterial efficacy to its native ciprofloxacin counterpart

Non-cystic fibrosis bronchiectasis (NCFB) characterized by permanent bronchial dilatation and recurrent infections has been clinically managed by long-term intermittent inhaled antibiotic therapy among other treatments. Herein we investigated dry powder inhaler (DPI) formulation of ciprofloxacin (CIP) nanoplex with mannitol/lactose as the excipient for NCFB therapy. The DPI of CIP nanoplex was evaluated against DPI of native CIP in terms of their (1) dissolution characteristics in artificial sputum medium, (2) ex vivo mucus permeability in sputum from NCFB and healthy individuals, (3) antibacterial efficacy in the presence of sputum against clinical Pseudomonas aeruginosa strains (planktonic and biofilm), and (4) cytotoxicity towards human lung epithelial cells. Despite their similarly fast dissolution rates in sputum, the DPI of CIP nanoplex exhibited superior mucus permeability to the native CIP (5-7 times higher) attributed to its built-in ability to generate highly supersaturated CIP concentration in the sputum. The superior mucus permeability led to the CIP nanoplex's higher antibacterial efficacy (>3 log₁₀ CFU/mL). The DPI of CIP nanoplex exhibited similar cytotoxicity towards the lung epithelial cells as the native CIP indicating its low risk of toxicity. These results established the promising potential of DPI of CIP nanoplex as a new therapeutic avenue for NCFB.

Oral versus inhaled antibiotics for bronchiectasis

BACKGROUND

Bronchiectasis is a chronic inflammatory disease characterised by a recurrent cycle of respiratory bacterial infections associated with cough, sputum production and impaired quality of life. Antibiotics are the main therapeutic option for managing bronchiectasis exacerbations. Evidence suggests that inhaled antibiotics may be associated with more effective eradication of infective organisms and a lower risk of developing antibiotic resistance when compared with orally administered antibiotics. However, it is currently unclear whether antibiotics are more effective when administered orally or by inhalation.

OBJECTIVES

To determine the comparative efficacy and safety of oral versus inhaled antibiotics in the treatment of adults and children with bronchiectasis.

SEARCH METHODS

We identified studies through searches of the Cochrane Airways Group's Specialised Register (CAGR), which is maintained by the Information Specialist for the group. The Register contains trial reports identified through systematic searches of bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, AMED, and PsycINFO, and handsearching of respiratory journals and meeting abstracts. We also searched ClinicalTrials.gov and the WHO trials portal. We searched all databases in March 2018 and imposed no restrictions on language of publication.

SELECTION CRITERIA

We planned to include studies which compared oral antibiotics with inhaled antibiotics. We would have considered short-term use (less than four weeks) for treating acute exacerbations separately from longer-term use as a prophylactic (4 weeks or more). We would have considered both intraclass and interclass comparisons. We planned to exclude studies if the participants received continuous or high-dose antibiotics immediately before the start of the trial, or if they have received a diagnosis of cystic fibrosis (CF), sarcoidosis, active allergic bronchopulmonary aspergillosis or active non-tuberculous Mycobacterial infection.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied study inclusion criteria to the searches and we planned for two authors to independently extract data, assess risk of bias and assess overall quality of the evidence using GRADE criteria. We also planned to obtain missing data from the authors where possible and to report results with 95% confidence intervals (CIs).

MAIN RESULTS

We identified 313 unique records through database searches and a further 21 records from trial registers. We excluded 307 on the basis of title and abstract alone and a further 27 after examining full-text reports. No studies were identified for inclusion in the review.

AUTHORS' CONCLUSIONS

There is currently no evidence indicating whether orally administered antibiotics are more beneficial compared to inhaled antibiotics. The recent ERS bronchiectasis guidelines provide a practical approach to the use of long-term antibiotics. New research is needed comparing inhaled versus oral antibiotic therapies for bronchiectasis patients with a history of frequent exacerbations, to establish which approach is the most effective in terms of exacerbation prevention, quality of life, treatment burden, and antibiotic resistance.