Inhaled antibiotics therapy for stable non-cystic fibrosis bronchiectasis: a meta-analysis

Inhibitors of the Elastase LasB for the Treatment of Pseudomonas aeruginosa Lung Infections

Infections caused by the Gram-negative pathogen Pseudomonas aeruginosa are emerging worldwide as a major threat to human health. Conventional antibiotic monotherapy suffers from rapid resistance development, underlining urgent need for novel treatment concepts. Here, we report on a nontraditional approach to combat P. aeruginosa-derived infections by targeting its main virulence factor, the elastase LasB. We discovered a new chemical class of phosphonates with an outstanding in vitro ADMET and PK profile, auspicious activity both in vitro and in vivo. We established the mode of action through a cocrystal structure of our lead compound with LasB and in several in vitro and ex vivo models. The proof of concept of a combination of our pathoblocker with levofloxacin in a murine neutropenic lung infection model and the reduction of LasB protein levels in blood as a proof of target engagement demonstrate the great potential for use as an adjunctive treatment of lung infections in humans.

Prevalence, trends and outcomes of long-term inhaled antibiotic treatment in people with cystic fibrosis without chronic Pseudomonas aeruginosa infection - A European cystic fibrosis patient registry data analysis

BACKGROUND

Long-term treatment with inhaled antibiotics is recommended for people with cystic fibrosis (pwCF) chronically infected with Pseudomonas aeruginosa (PA). However, pwCF without chronic PA infection are also commonly treated with inhaled antibiotics. Using data from the European Cystic Fibrosis Patient Registry (ECFSPR) we aimed to determine the prevalence and factors associated with inhaled antibiotic treatment in pwCF without chronic PA infection, and long-term outcomes with inhaled antibiotics use.

METHODS

The ECFSPR was searched for pwCF 6 years of age and older who were not chronically infected with PA at baseline. Factors associated with inhaled antibiotic use were first assessed through a logistic regression. From this model a propensity score was computed for each individual, providing the likelihood of being treated with inhaled antibiotics. Long-term outcomes with and without inhaled antibiotics were assessed separately for propensity scores tertiles.

RESULTS

7210 pwCF without chronic PA infection at baseline were included, with 2722 (37.75%) receiving long-term treatment with inhaled antibiotics. Treatment with inhaled antibiotics was more prevalent with severe genotype, diabetes, pancreatic insufficiency, and past infection with chronic PA (OR 3.8, 95% CI, 2.88-5.04). Treatment with inhaled antibiotics was not associated with a reduced risk for acquisition of PA or other resistant pathogens, or with improved lung function decline, mortality, or transplantation.

CONCLUSIONS

Many pwCF without chronic PA infection are receiving long-term treatment with inhaled antibiotics despite lack of support from clinical trials or practice guidelines. We did not observe improve outcomes with inhaled antibiotics. Our findings suggest controlled studies evaluating specific inhaled antibiotic regimens targeting specific pathogens or indications be performed to determine their effect.

Inhaled Antibiotics in Non-cystic Fibrosis Bronchiectasis (NCFB): A Systematic Review of Efficacy and Limitations in Adult Patients

Non-cystic fibrosis bronchiectasis has recently been under the spotlight due to a better detection rate with advanced imaging techniques. Recurrent infections in such patients are the main cause of their deterioration. This invariably leads to a catastrophic wheel of decline in lung function, reinfection, and repeated hospital consultations. The main goal of their management is based on the principles of prevention and vigorous treatment of recurrent infections. This review aimed to gather recent therapeutic options for inhaled antibacterial use in such patients and compare them for their properties of safety and efficacy. Studies done in the last 10 years on adult patients were gathered using the Medical Subject Headings (MeSH) strategy and later sorted using the inclusion/exclusion criteria. Research engines used include Google Scholar, PubMed, and the Saudi Digital Library. Out of the 31,739 articles identified initially, 1362 were screened. The final eight selected papers were assessed for quality by using the quality assessment checklist, the Cochrane bias assessment tool, the Scale for the Assessment of Narrative Review Articles (SANRA) tools and cross-examined by co-authors. We concluded that the use of inhaled antibiotics as an adjuvant and follow-up treatment option is associated with better short and long-term prognoses in patients. They lead to lesser systemic side effects than the oral and intravenous varieties available on the market. However, the establishment of a hierarchy among the subgroups remains a grey area that needs further research.

Testing the effects of combining azithromycin with inhaled tobramycin for P. aeruginosa in cystic fibrosis: a randomised, controlled clinical trial

RATIONALE

Inhaled tobramycin and oral azithromycin are common chronic therapies in people with cystic fibrosis and Pseudomonas aeruginosa airway infection. Some studies have shown that azithromycin can reduce the ability of tobramycin to kill P. aeruginosa. This trial was done to test the effects of combining azithromycin with inhaled tobramycin on clinical and microbiological outcomes in people already using inhaled tobramycin. We theorised that those randomised to placebo (no azithromycin) would have greater improvement in forced expiratory volume in one second (FEV1) and greater reduction in P. aeruginosa sputum in response to tobramycin.

METHODS

A 6-week prospective, randomised, placebo-controlled, double-blind trial testing oral azithromycin versus placebo combined with clinically prescribed inhaled tobramycin in individuals with cystic fibrosis and P. aeruginosa airway infection.

RESULTS

Over a 6-week period, including 4 weeks of inhaled tobramycin, the relative change in FEV1 did not statistically significantly differ between groups (azithromycin (n=56) minus placebo (n=52) difference: 3.44%; 95% CI: -0.48 to 7.35; p=0.085). Differences in secondary clinical outcomes, including patient-reported symptom scores, weight and need for additional antibiotics, did not significantly differ. Among the 29 azithromycin and 35 placebo participants providing paired sputum samples, the 6-week change in P. aeruginosa density differed in favour of the placebo group (difference: 0.75 log10 CFU/mL; 95% CI: 0.03 to 1.47; p=0.043).

CONCLUSIONS

Despite having greater reduction in P. aeruginosa density in participants able to provide sputum samples, participants randomised to placebo with inhaled tobramycin did not experience significantly greater improvements in lung function or other clinical outcomes compared with those randomised to azithromycin with tobramycin.

Safety and Efficacy of Devices Delivering Inhaled Antibiotics among Adults with Non-Cystic Fibrosis Bronchiectasis: A Systematic Review and a Network Meta-Analysis

It remains unknown whether the type of aerosol generating device is affecting efficacy and safety among non-cystic fibrosis bronchiectasis (NCFB) adults. The proposal of this network meta-analysis (NMA) is to evaluate effectiveness and safety of inhaled antibiotics administered via dry powder inhaler (DPI) and via nebulizers (SVN) among adult patients with NCFB. Inclusion criteria were randomized-controlled trials, adults (≥18 years) with NCFB, and inhaled antibiotics administered via DPI as intervention. Search strategy was performed in PubMed, Web of Science, and Cochrane Library from 2000 to 2019. Sixteen trials (2870 patients) were included. Three trials (all ciprofloxacin) used DPIs and thirteen used SVN (three ciprofloxacin). Both DPI and SVN devices achieved similar safety outcomes (adverse events, antibiotic discontinuation, severe adverse events, and bronchospasm). Administration of ciprofloxacin via DPI significantly improved time to first exacerbation (87 days, 95% CI 34.3–139.7) and quality of life (MD −7.52; 95% CI −13.06 to −1.98) when compared with via SVN. No other significant differences were documented in clinical efficacy (at least one exacerbation, FEV₁% predicted) and microbiologic response (bacterial eradication, emergence of new potential pathogens, and emergence of antimicrobial resistance) when comparing devices. Our NMA documented that time to first exacerbation and quality of life, were more favorable for DPIs. Decisions on the choice of devices should incorporate these findings plus other criteria, such as simplicity, costs or maintenance requirements.

ERS International Congress 2021: highlights from the Respiratory Infections Assembly

The European Respiratory Society Annual Congress 2021 took place virtually for the second year running due to the coronavirus pandemic. The congress programme featured more than 400 sessions and 3000 abstract presentations, covering the entire respiratory science and medicine field. In this article, Early Career Members of the Respiratory Infections Assembly summarise a selection of sessions across a broad range of topics, including presentations on bronchiectasis, non-tuberculosis mycobacteria, tuberculosis, cystic fibrosis and COVID-19.

Safety and tolerability of inhaled antibiotics in patients with bronchiectasis

INTRODUCTION

Bronchiectasis is typically treated with inhaled antibiotics in clinical practice. However, there is a striking lack of standardised procedures for the preparation of noncommercial solutions. We used biochemical parameters to analyse the safety and tolerability of inhaled antibiotics in patients with bronchiectasis, and determined potential associations between the inhaled antibiotics used and adherence to the medications and quality of life.

METHODS

We conducted a literature review, biochemical testing, and a pilot study of patients admitted to our hospital with noncystic fibrosis bronchiectasis. The MEDLINE database was searched for studies involving inhaled antibiotics to treat bronchiectasis. We analysed the pH, osmolality, and sodium and chloride ion concentrations of the antibiotics used. The pilot study included patients receiving inhaled antibiotic treatment. Demographic data, adherence, and quality of life were recorded and assessed. We determined potential associations between the study variables.

RESULTS

The literature review identified 429 articles: 106 included precise instructions for diluting antibiotics, and 18 reported data on the biochemical parameters analysed. Laboratory results showed that some antibiotic dilutions were outside the range of tolerability, especially those involving dry powders for intravenous infusion, which must be diluted for their inhalation. Adherence was good in more than 80% of the patients, and higher in men and older patients. Men reported better quality of life. No associations were found between the antibiotics used and the other variables.

CONCLUSION

Regarding the biochemical parameters analysed, there is a lack of information on the tolerability and biochemical safety of noncommercial dilutions of inhaled antibiotics used to treat bronchiectasis.

Pseudomonas aeruginosa in bronchiectasis: infection, inflammation, and therapies

Introduction: Bronchiectasis is a chronic endobronchial suppurative disease characterized by irreversibly dilated bronchi damaged by repeated polymicrobial infections and predominantly, neutrophilic airway inflammation. Some consider bronchiectasis a syndromic consequence of several different causes whilst others view it as an individual disease entity. In most patients, identifying an underlying cause remains challenging. The acquisition and colonization of affected airways by Pseudomonas aeruginosa represent a critical and adverse clinical consequence for its progression and management.Areas covered: In this review, we outline clinical and pre-clinical peer-reviewed research published in the last 5 years, focusing on the pathogenesis of bronchiectasis and the role of P. aeruginosa and its virulence in shaping host inflammatory and immune responses in the airway. We further detail its role in airway infection, the lung microbiome, and address therapeutic options in bronchiectasis.Expert opinion: P. aeruginosa represents a key pulmonary pathogen in bronchiectasis that causes acute and/or chronic airway infection. Eradication can prevent adverse clinical consequence and/or disease progression. Novel therapeutic strategies are emerging and include combination-based approaches. Addressing airway infection caused by P. aeruginosa in bronchiectasis is necessary to prevent airway damage, loss of lung function and exacerbations, all of which contribute to adverse clinical outcome.

Development of Inhalable Nanostructured Lipid Carriers for Ciprofloxacin for Noncystic Fibrosis Bronchiectasis Treatment

Purpose

Ciprofloxacin (CIP) has poor lung targeting after oral inhalation. This study developed optimized inhalable nanostructured lipid carriers (NLCs) for CIP to enhance deposition and accumulation in deeper parts of the lungs for treatment of noncystic fibrosis bronchiectasis (NCFB).

Methods

NLC formulations based on stearic acid and oleic acid were successfully prepared by hot homogenization and in vitro-characterized. CIP-NLCs were formulated into nanocomposite micro particles (NCMPs) for administration in dry powder inhalation (DPI) formulations by spray-drying (SD) using different ratios of chitosan (CH) as a carrier. DPI formulations were evaluated for drug content and in vitro deposition, and their mass median aerodynamic diameter (MMAD), fine particle fraction (FPF), fine particle dose (FPD), and emitted dose (ED) were determined.

Results

The CIP-NLCs were in the nanometric size range (102.3 ± 4.6 nm), had a low polydispersity index (0.267 ± 0.12), and efficient CIP encapsulation (98.75% ± 0.048%), in addition to a spherical and smooth shape with superior antibacterial activity. The in vitro drug release profile of CIP from CIP-NLCs showed 80% release in 10 h. SD of CIP-NLCs with different ratios of CH generated NCMPs with good yield (>65%). The NCMPs had a corrugated surface, but with increasing lipid:CH ratios, more spherical, smooth, and homogenous NCMPs were obtained. In addition, there was a significant change in the FPF with increasing lipid:CH ratios (P ˂ 0.05). NCMP-1 (lipid:CH = 1:0.5) had the highest FPD (45.0 µg) and FPF (49.2%), while NCMP-3 (lipid:CH = 1:1.5) had the lowest FPF (37.4%). All NCMP powders had an MMAD in the optimum size range of 3.9–5.1 μm.

Conclusion

Novel inhalable CIP NCMP powders are a potential new approach to improved target ability and delivery of CIP for NCFB treatment.

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.