The Rationale and Evidence for Use of Inhaled Antibiotics to Control Pseudomonas aeruginosa Infection in Non-cystic Fibrosis Bronchiectasis

Pseudomonas aeruginosa mucinous phenotypes and algUmucABD operon mutant characteristics obtained from inpatients with bronchiectasis and their correlation with acute aggravation

Objective

Although the mechanism is unclear, Pseudomonas aeruginosa (PA) infection directly affects the frequency of acute exacerbations in patients with bronchiectasis. The aims of this article are to analyze the genetic mutation characteristics of the algUmucABD operon in PA, isolated from hospitalized patients with bronchiectasis, and to explore independent risk factors for frequent acute exacerbations of bronchiectasis.

Methods

Based on the number of acute exacerbations that occurred in the past year, these patients with bronchiectasis were divided into those with frequent acute exacerbations (Group A) and those with non-frequent acute exacerbations (Group B). We identified the distribution of mucoid phenotypes (MPs) and alginate morphotypes (AMs) in PA, and classified them into I-IV categories based on their different AMs; otherwise, the gene mutation types (GMTs) of the algUmucABD operon were tested. Subsequently, the relationship between GMT, MP, and AM and the independent risk factors for frequent acute exacerbations in patients with bronchiectasis were explored.

Results

A total of 93 patients and 75 PA strains, from January 2019 to August 2023, were included in this study. The MP and AM distributions of PA were as follows: 64 strains (85.33%) of mucoid (the AMs were 38 strains of type I, 3 strains of type II, and 23 strains of type IV) and 11 strains of non-mucoid (the AM was type III only). Mucoid PA with algU, mucA, mucB, and mucD mutations accounted for 19.61%, 74.51%, 31.37%, and 50.98%, respectively. GMT was divided into the following: mucA mutations only, mucA combined with other gene mutations, other gene mutations without mucA mutations, and without gene mutations. In 91.7% of PA with type I of AM, only mucA mutations occurred, and in both separate MP and AM, the GMT differences were statistically significant. Lastly, the number of lung lobes with bronchiectasis and the number of PA with mucA mutations only were the independent risk factors for frequent acute exacerbations.

Conclusion

The mucA mutation was primarily responsible for the mucoid of MP and type I of AM in PA, and it was also an independent risk factor for frequent exacerbations of bronchiectasis.

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.

The Respiratory Microbiome in Paediatric Chronic Wet Cough: What Is Known and Future Directions

Chronic wet cough for longer than 4 weeks is a hallmark of chronic suppurative lung diseases (CSLD), including protracted bacterial bronchitis (PBB), and bronchiectasis in children. Severe lower respiratory infection early in life is a major risk factor of PBB and paediatric bronchiectasis. In these conditions, failure to clear an underlying endobronchial infection is hypothesised to drive ongoing inflammation and progressive tissue damage that culminates in irreversible bronchiectasis. Historically, the microbiology of paediatric chronic wet cough has been defined by culture-based studies focused on the detection and eradication of specific bacterial pathogens. Various 'omics technologies now allow for a more nuanced investigation of respiratory pathobiology and are enabling development of endotype-based models of care. Recent years have seen substantial advances in defining respiratory endotypes among adults with CSLD; however, less is understood about diseases affecting children. In this review, we explore the current understanding of the airway microbiome among children with chronic wet cough related to the PBB-bronchiectasis diagnostic continuum. We explore concepts emerging from the gut-lung axis and multi-omic studies that are expected to influence PBB and bronchiectasis endotyping efforts. We also consider how our evolving understanding of the airway microbiome is translating to new approaches in chronic wet cough diagnostics and treatments.

Nanomedical research and development in Spain: improving the treatment of diseases from the nanoscale

The new and unique possibilities that nanomaterials offer have greatly impacted biomedicine, from the treatment and diagnosis of diseases, to the specific and optimized delivery of therapeutic agents. Technological advances in the synthesis, characterization, standardization, and therapeutic performance of nanoparticles have enabled the approval of several nanomedicines and novel applications. Discoveries continue to rise exponentially in all disease areas, from cancer to neurodegenerative diseases. In Spain, there is a substantial net of researchers involved in the development of nanodiagnostics and nanomedicines. In this review, we summarize the state of the art of nanotechnology, focusing on nanoparticles, for the treatment of diseases in Spain (2017-2022), and give a perspective on the future trends and direction that nanomedicine research is taking.

The value of biofilm testing to guide antimicrobial stewardship in chronic respiratory diseases

Introduction

Biofilm production is an important yet currently overlooked aspect of diagnostic microbiology that has implications for antimicrobial stewardship. In this study, we aimed to validate and identify additional applications of the BioFilm Ring Test® (BRT) for Pseudomonas aeruginosa (PA) isolates from patients with bronchiectasis (BE).

Materials and methods

Sputa were collected from BE patients who had at least one PA positive culture in the previous year. We processed the sputa to isolate both mucoid and non-mucoid PA, and determined their susceptibility pattern, mucA gene status, and presence of ciprofloxacin mutations in QRDR genes. The Biofilm production index (BPI) was obtained at 5 and 24 hours. Biofilms were imaged using Gram staining.

Results

We collected 69 PA isolates, including 33 mucoid and 36 non-mucoid. A BPI value below 14.75 at 5 hours predicted the mucoid PA phenotype with 64% sensitivity and 72% specificity.

Conclusion

Overall, our findings suggest that the fitness-cost associated with the mucoid phenotype or ciprofloxacin resistance is shown through a time-dependent BPI profile. The BRT has the potential to reveal biofilm features with clinical implications.

Impact of fluoroquinolones and aminoglycosides on P. aeruginosa virulence factor production and cytotoxicity

The opportunistic pathogen Pseudomonas aeruginosa is one of leading causes of disability and mortality worldwide and the world health organisation has listed it with the highest priority for the need of new antimicrobial therapies. P. aeruginosa strains responsible for the poorest clinical outcomes express either ExoS or ExoU, which are injected into target host cells via the type III secretion system (T3SS). ExoS is a bifunctional cytotoxin that promotes intracellular survival of invasive P. aeruginosa by preventing targeting of the bacteria to acidified intracellular compartments. ExoU is a phospholipase which causes destruction of host cell plasma membranes, leading to acute tissue damage and bacterial dissemination. Fluoroquinolones are usually employed as a first line of therapy as they have been shown to be more active against P. aeruginosa in vitrothan other antimicrobial classes. Their overuse over the past decade, however, has resulted in the emergence of antibiotic resistance. In certain clinical situations, aminoglycosides have been shown to be more effective then fluoroquinolones, despite their reduced potency towards P. aeruginosa in vitro. In this study, we evaluated the effects of fluoroquinolones (moxifloxacin and ciprofloxacin) and aminoglycosides (tobramycin and gentamycin) on T3SS expression and toxicity, in corneal epithelial cell infection models. We discovered that tobramycin disrupted T3SS expression and reduced both ExoS and ExoU mediated cytotoxicity, protecting infected HCE-t cells at concentrations below the minimal inhibitory concentration (MIC). The fluoroquinolones moxifloxacin and ciprofloxacin, however, up-regulated the T3SS and did not inhibit and may have increased the cytotoxic effects of ExoS and ExoU.

Management of chronic Pseudomonas aeruginosa infection with inhaled levofloxacin in people with cystic fibrosis

People with cystic fibrosis (CF) are highly susceptible to bacterial infections of the airways. By adulthood, chronic Pseudomonas aeruginosa (Pa) is the most prevalent infective organism and is difficult to eradicate owing to its adaptation to the CF lung microenvironment. Long-term suppressive treatment with inhaled antimicrobials is the standard care for reducing exacerbation frequency, improving quality of life and increasing measures of lung function. Levofloxacin (a fluoroquinolone antimicrobial) has been approved as an inhaled solution in Europe and Canada, for the treatment of adults with CF with chronic P. aeruginosa pulmonary infections. Here, we review the clinical principles relating to the use of inhaled antimicrobials and inhaled levofloxacin for the management of P. aeruginosa infections in patients with CF.

Inhaled antibiotics for treatment of adults with non-cystic fibrosis bronchiectasis: A systematic review and meta-analysis

BACKGROUND

Inhaled antibiotics (IA) in non-cystic fibrosis bronchiectasis (NCFB) are recommended by some clinical practice guidelines for prevention or treatment of NCFB exacerbations.

METHODS

We performed a systematic review and meta-analysis to evaluate the efficacy and safety of IA use for treatment of adults with NCFB and Pseudomonas aeruginosa chronic bronchial infection. The search was performed in the Cochrane Library, PubMed, and Web of Science databases from 2000 to 2019. Studies of IA for treatment of stable or exacerbated NCFB adults (≥18 years) with P. aeruginosa infection were considered eligible. PROSPERO Registration number: CRD42019136154.

RESULTS

Twelve trials (2476 participants) were included. IA therapy increased P. aeruginosa eradication from sputum in patients with exacerbations (OR: 3.19, 95%CI: 1.70-5.99) with similar effects on stable patients (OR: 7.22, 95%CI: 2.81-18.59), and a trend to reduced emergence of new respiratory pathogens (OR: 0.58, 95%CI: 0.28-1.18). IA achieved significant reduced exacerbation rates (RR: 0.90; 95%CI: 0.82-0.98) in stable patients, with a number needed to treat (NNT) of 59, but no significant changes in FEV₁, mortality, hospitalizations or quality of life were identified. In stable patients, IA use increased antimicrobial resistance (RR: 2.10, 95%CI: 1.35-3.27) at the end of therapy, with a number needed to treat of 6.

CONCLUSIONS

IA therapy achieved a statistically significant eradication of P. aeruginosa from sputum, with a 10% reduction of exacerbations in stable patients. This effect has to be balanced with significant increases in antimicrobial resistance. Our meta-analysis failed to show a significant benefit in terms of patient-centered outcomes.

Liposomal drug delivery to manage nontuberculous mycobacterial pulmonary disease and other chronic lung infections

Nontuberculous mycobacterial (NTM) pulmonary disease is a chronic respiratory infection associated with declining lung function, radiological deterioration and significantly increased morbidity and mortality. Patients often have underlying lung conditions, particularly bronchiectasis and COPD. NTM pulmonary disease is difficult to treat because mycobacteria can evade host defences and antimicrobial therapy through extracellular persistence in biofilms and sequestration into macrophages. Management of NTM pulmonary disease remains challenging and outcomes are often poor, partly due to limited penetration of antibiotics into intracellular spaces and biofilms. Efficient drug delivery to the site of infection is therefore a key objective of treatment, but there is high variability in lung penetration by antibiotics. Inhalation is the most direct route of delivery and has demonstrated increased efficacy of antibiotics like amikacin compared with systemic administration. Liposomes are small, artificial, enclosed spherical vesicles, in which drug molecules can be encapsulated to provide controlled release, with potentially improved pharmacokinetics and reduced toxicity. They are especially useful for drugs where penetration of cell membranes is essential. Inhaled delivery of liposomal drug solutions can therefore facilitate direct access to macrophages in the lung where the infecting NTM may reside. A range of liposomal drugs are currently being evaluated in respiratory diseases.

Liposome-encapsulated antibiotics can optimise respiratory disease treatment. Amikacin liposomal inhalation suspension is effective in nontuberculous mycobacterial pulmonary disease that has failed to convert following oral guideline-based therapy.https://bit.ly/3f3ixIu

In Vitro Activity of a Novel Siderophore-Cephalosporin LCB10-0200 (GT-1), and LCB10-0200/Avibactam, against Carbapenem-Resistant Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa Strains at a Tertiary Hospital in Korea

The siderophore-antibiotic conjugate LCB10-0200 (a.k.a. GT-1) has been developed to combat multidrug-resistant Gram-negative bacteria. In this study, the in vitro activity of LCB10-0200 and LCB10-0200/avibactam (AVI) has been investigated against carbapenem-resistant Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa. Minimal inhibitory concentrations (MICs) of LCB10-0200, LCB10-0200/AVI, aztreonam, aztreonam/AVI, ceftazidime, ceftazidime/AVI, and meropenem were measured using the agar dilution method. Whole genome sequencing was performed using Illumina and the resistome was analyzed. LCB10-0200 displayed stronger activity than the comparator drugs in meropenem-resistant E. coli and K. pneumoniae, and the addition of AVI enhanced the LCB10-0200 activity to MIC ≤ 0.12 mg/L for 90.5% of isolates. In contrast, whereas LCB10-0200 alone showed potent activity against meropenem-resistant A. baumannii and P. aeruginosa at MIC ≤ 4 mg/L for 84.3% of isolates, the combination with AVI did not improve its activity. LCB10-0200/AVI was active against CTX-M-, SHV-, CMY-, and KPC- producing E. coli and K. pneumoniae, while LCB10-0200 alone was active against ADC-, OXA-, and VIM- producing A. baumannii and P. aeruginosa. Both LCB10-0200 and LCB10-0200/AVI displayed low activity against IMP- and NDM- producing strains. LCB10-0200 alone exhibited strong activity against selected strains. The addition of AVI significantly increased LCB10-0200 activity against carbapenem-resistant E. coli, K. pneumoniae.

Antimicrobial Resistance in Common Respiratory Pathogens of Chronic Bronchiectasis Patients: A Literature Review

Non-cystic fibrosis bronchiectasis is a chronic disorder in which immune system dysregulation and impaired airway clearance cause mucus accumulation and consequent increased susceptibility to lung infections. The presence of pathogens in the lower respiratory tract causes a vicious circle resulting in impaired mucociliary function, bronchial inflammation, and progressive lung injury. In current guidelines, antibiotic therapy has a key role in bronchiectasis management to treat acute exacerbations and chronic infection and to eradicate bacterial colonization. Contrastingly, antimicrobial resistance, with the risk of multidrug-resistant pathogen development, causes nowadays great concern. The aim of this literature review was to assess the role of antibiotic therapy in bronchiectasis patient management and possible concerns regarding antimicrobial resistance based on current evidence. The authors of this review stress the need to expand research regarding bronchiectasis with the aim to assess measures to reduce the rate of antimicrobial resistance worldwide.

Inhaled tobramycin for chronic infection with pseudomonas aeruginosa in non-cystic fibrosis bronchiectasis: A systematic review and meta-analysis

INTRODUCTION

Non-cystic fibrosis bronchiectasis (NCFBE) is a chronic and progressive disease characterized by the permanent destruction of small and mid-sized airways. Many patients are chronically colonized by Pseudomona aueruginosa, for which oral antibiotics are given. Evidence to support the use of inhaled antibiotics is contradictory.

OBJECTIVE

To describe the clinical effects of inhaled Tobramycin in P. aeruginosa density in sputum and eradication, lung function, bacterial resistance, and exacerbations requiring hospital admission, in the context of patients with NCFBE colonized by P. aeruginosa.

METHODS

We included RCTs comparing inhaled tobramycin to other antibiotics and placebo in patients with NCFBE.

MAIN FINDINGS

5 studies with 211 participants were included. 2 studies reported a significant but transitory decrease in P. aeruginosa density in sputum as compared to placebo. There was a small difference in the eradication of P. aeruginosa among groups, although with very wide confidence intervals. Tobramycin reduced the rate of hospital admissions but no frequency of exacerbations. There was no evidence of an increased rate of bacterial resistance but was associated to respiratory adverse effects.

CONCLUSIONS

Evidence is not robust enough to confirm a benefit of inhaled Tobramycin in reducing P. aeruginosa sputum density or eradication. There was a high attrition rate, in part due to respiratory adverse events after drug administration, which affects interpretation of the data and raises concerns about the tolerability of the drug. Further network meta-analysis should be done to compare the efficacy and safety of different inhaled antibiotics.

Current choices of antibiotic treatment for Pseudomonas aeruginosa infections

PURPOSE OF REVIEW

Pseudomonas aeruginosa is one of the most feared nosocomial pathogens. Treatment of P. aeruginosa infections is challenging because of the limited choices of antibiotics and the emergent resistance of the pathogen. The present review aims at addressing the management of P. aeruginosa infections and highlighting the novel antibiotics that show a future promising role.

RECENT FINDINGS

Novel fluoroquinolones have been recently introduced and show favorable activity. New combinations of β-lactams/β-lactamase inhibitors have been studied in various indications of infections because of P. aeruginosa. Cefiderocol, a new cephalosporin, shows very promising results against P. aeruginosa. Currently, combination therapy is only recommended in limited scenarios. Extended-infusion of β-lactams exhibit clinical benefit. Bacteriophage therapy is a growing field of interest and may have an impactful effect on the treatment of resistant P. aeruginosa.

SUMMARY

Factors that guide clinical decisions for empiric and directed P. aeruginosa therapy include the epidemiology, the patient's risk factors, the site of infection, and the available treatment options. Conventional antipseudomonal antibiotics have been used successfully for a long time, but the increase in worldwide resistance necessitates the need for newer agents. Antimicrobial stewardship is essential to preserve the new drugs and prevent future development of resistance.

Micro/nanosystems and biomaterials for controlled delivery of antimicrobial and anti-biofilm agents

INTRODUCTION

Microbial resistance is a severe problem for clinical practice due to misuse of antibiotics that promotes the development of surviving strategies by bacteria and fungi. Microbial cells surrounded by a self-produced polymer matrix, defined as biofilms, are inherently more difficult to eradicate. Biofilms endow bacteria with a unique resistance against antibiotics and other anti-microbial agents and play a crucial role in chronic infection.

AREAS COVERED

Biofilm-associated antimicrobial resistance in the lung and wounds. Existing inhaled therapies for treatment of biofilm-associated lung infections. Role of pharmaceutical nanotechnologies to fight resistant microbes and biofilms.

EXPERT OPINION

The effectiveness of antibiotics has gradually decreased due to the onset of resistance phenomena. The formation of biofilms represents one of the most important steps in the development of resistance to antimicrobial treatment. The most obvious solution for overcoming this criticality would be the discovery of new antibiotics. However, the number of new molecules with antimicrobial activity brought into clinical development has considerably decreased. In the last decades the development of innovative drug delivery systems, in particular those based on nanotechnological platforms, has represented the most effective and economically affordable approach to optimize the use of available antibiotics, improving their effectiveness profile. Abbreviations AZT: Aztreonam; BAT: Biofilm antibiotic tolerance; CF: Cystic Fibrosis; CIP: Ciprofloxacin; CRS: Chronic Rhinosinusitis; DPPG: 1,2-dipalmytoyl-sn-glycero-3-phosphoglycerol; DSPC: 1,2-distearoyl-sn-glycero-phosphocholine sodium salt; EPS: extracellular polymeric substance; FEV1: Forced Expiratory Volume in the first second; GSNO: S-nitroso-glutathione; LAE: lauroyl arginate ethyl; MIC: Minimum inhibitory Concentration; NCFB: Non-Cystic Fibrosis Bronchiectasis; NTM: Non-Tuberculous Mycobacteria; NTM-LD: Non-tuberculous mycobacteria Lung Disease PA: Pseudomonas aeruginosa; pDMAEMA: poly(dimethylaminoethyl methacrylate);pDMAEMA-co-PAA-co-BMA: poly(dimethylaminoethyl methacrylate)-co-propylacrylic acid-co-butyl methacrylate; PEG: polyethylene glycol; PEGDMA: polyethylene glycol dimethacrylate;PCL: Poly-ε-caprolactone; PLA: poly-lactic acid; PLGA: poly-lactic-co-glycolic acid; PVA: poli-vinyl alcohol; SA: Staphylococcus aureus; TIP: Tobramycin Inhalation Powder; TIS: Tobramycin Inhalation Solution; TPP: Tripolyphosphate.

Preclinical Development of Orally Inhaled Drugs (OIDs)-Are Animal Models Predictive or Shall We Move Towards In Vitro Non-Animal Models?

Respiratory diseases constitute a huge burden in our society, and the global respiratory drug market currently grows at an annual rate between 4% and 6%. Inhalation is the preferred administration method for treating respiratory diseases, as it: (i) delivers the drug directly at the site of action, resulting in a rapid onset; (ii) is painless, thus improving patients' compliance; and (iii) avoids first-pass metabolism reducing systemic side effects. Inhalation occurs through the mouth, with the drug generally exerting its therapeutic action in the lungs. In the most recent years, orally inhaled drugs (OIDs) have found application also in the treatment of systemic diseases. OIDs development, however, currently suffers of an overall attrition rate of around 70%, meaning that seven out of 10 new drug candidates fail to reach the clinic. Our commentary focuses on the reasons behind the poor OIDs translation into clinical products for the treatment of respiratory and systemic diseases, with particular emphasis on the parameters affecting the predictive value of animal preclinical tests. We then review the current advances in overcoming the limitation of animal animal-based studies through the development and adoption of in vitro, cell-based new approach methodologies (NAMs).

Non-CF bronchiectasis: Orphan disease no longer

Bronchiectasis is a complex, chronic respiratory condition, characterized by frequent cough and exertional dyspnea due to a range of conditions that include inherited mucociliary defects, inhalational airway injury, immunodeficiency states and prior respiratory infections. For years, bronchiectasis was classified as either being caused by cystic fibrosis or non-cystic fibrosis. Non-cystic fibrosis bronchiectasis, once considered an orphan disease, is more prevalent worldwide in part due to greater availability of chest computed tomographic imaging. Identification of the cause of non-cystic fibrosis bronchiectasis with the use of chest imaging, laboratory testing, and microbiologic assessment of airway secretions can lead to initiation of specific therapies aimed at slowing disease progression. Nonpharmacologic therapies such as airway clearance techniques and pulmonary rehabilitation improve patient symptoms. Inhaled corticosteroids should not be routinely prescribed unless concomitant asthma or COPD is present. Inhaled antibiotics prescribed to individuals with >3 exacerbations per year are well tolerated, reduce airway bacteria load and may reduce the frequency of exacerbations. Likewise, chronic macrolide therapy reduces the frequency of exacerbations. Medical therapies for cystic fibrosis bronchiectasis may not be effective in treatment of non-cystic fibrosis bronchiectasis.

Reducing the frequency of respiratory tract infections in severe neurological disorders by inhaled antibiotics: a retrospective data analysis

Background

In patients with severe neurological impairment, recurrent respiratory tract infections frequently occur as a result of impaired clearance of airway secretions and microbial airway colonisation. We hypothesised that inhaled antibiotic therapy may improve the morbidity of these patients.

Methods

A retrospective data analysis of 20 patients (11 nontracheotomised and nine tracheotomised) with neurological impairment and microbial airway colonisation was carried out at a children's university hospital. Two questionnaires that asked about the number of respiratory tract infections, antibiotic therapies and hospitalisations were distributed to the patients/caregivers: a first questionnaire representing the 12 months prior to the initiation of inhaled antibiotics and a second questionnaire describing the first 12 months under therapy.

Results

During the first 12 months of therapy, the frequency of respiratory tract infections among all participants was reduced from a mean of 6.8 episodes (median (interquartile range (IQR)) 6.0 (4.0–10.0) episodes) to a mean of 2.5 episodes (median (IQR) 2.0 (1.0–3.0) episodes; p<0.001). In addition, a significant decrease of systemic antibiotic therapies (mean 7.7, median (IQR) 6.0 (4.0–10.0) versus 2.5, 2.5 (0.0–3.75) episodes; p<0.001) and hospitalisations (mean 3.9, median (IQR) 3.5 (1.0–5.0) versus 0.9, 0.0 (0.0–1.0) episodes; p<0.001) was noted. This significant therapeutic effect could be demonstrated in a subgroup analysis in both tracheotomised and nontracheotomised subjects. The reduction of respiratory tract infections and systemic antibiotic therapies (and thus the therapeutic success) was significantly greater in the nontracheotomised group compared with the tracheotomised group.

Conclusions

The presented data suggest that inhaled antibiotics might play a role in treating recurrent respiratory tract infections in neuromuscular diseases.

Inhaled antibiotic therapy offers a novel approach to the prevention of respiratory tract infections in patients with severe neurological impairment who have chronic microbial airway colonisation and recurrent respiratory tract infectionshttp://bit.ly/2HQRyz0

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.

Spotlight on inhaled ciprofloxacin and its potential in the treatment of non-cystic fibrosis bronchiectasis

Non-cystic fibrosis bronchiectasis (NCFB) is a severe chronic illness characterized by irreversible dilation of airways and thickening of bronchial walls, chronic inflammation, repeated infections, and progressive obstruction of the airways. In contrast to cystic fibrosis bronchiectasis (CFB), which is a well-defined genetic disorder, NCFB is a heterogeneous disease caused by many different medical entities. Inhaled antibiotics are effective for patients with CFB, but their efficacy in NCFB has not been proven. The main pathogens involved in the colonization of patients with bronchiectasis are Haemophilus influenza, Moraxella catarrhalis, Staphylococcus aureus, and Pseudomonas aeruginosa. The latter is associated with increased morbidity and mortality. In addition, in NCFB, P. aeruginosa strains are frequently more resistant than those in CFB. At present, there are no approved inhaled antibiotic therapies for NCFB patients. Inhaled ciprofloxacin has been under investigation in the last few years. In two phase II randomized, double-blind, placebo-controlled trials, the use of inhaled ciprofloxacin was significantly associated with reduction in sputum bacterial density and greater eradication rates. In four phase III randomized, double-blind, placebo-controlled trials, the results regarding the time of the first exacerbation and the rate of exacerbations were inconsistent. Specifically, ORBIT-4 and RESPIRE-1 trials showed clinical benefit (prolongation of the time of the first exacerbation and reduced rate of exacerbations in the treatment group compared to the placebo group), whereas the ORBIT-3 and RESPIRE-2 failed to achieve their primary endpoints. The RESPIRE-1 was the first trial that examined the 14-days on/off course separate from the standard 28-days on/off regimen, which is based on CFB protocol treatments. The current data on the efficacy of inhaled ciprofloxacin are encouraging, but further evaluation is needed to determine the appropriate target group and the ideal duration of treatment.