Efficacy of aerosolized tobramycin in patients with cystic fibrosis

Limited effects of azithromycin on the oropharyngeal microbiome in children with CF and early pseudomonas infection

BACKGROUND

Tobramycin inhalation solution (TIS) and chronic azithromycin (AZ) have known clinical benefits for children with CF, likely due to antimicrobial and anti-inflammatory activity. The effects of chronic AZ in combination with TIS on the airway microbiome have not been extensively investigated. Oropharyngeal swab samples were collected in the OPTIMIZE multicenter, randomized, placebo-controlled trial examining the addition of AZ to TIS in 198 children with CF and early P. aeruginosa infection. Bacterial small subunit rRNA gene community profiles were determined. The effects of TIS and AZ were assessed on oropharyngeal microbial diversity and composition to uncover whether effects on the bacterial community may be a mechanism of action related to the observed changes in clinical outcomes.

RESULTS

Substantial changes in bacterial communities (total bacterial load, diversity and relative abundance of specific taxa) were observed by week 3 of TIS treatment for both the AZ and placebo groups. On average, these shifts were due to changes in non-traditional CF taxa that were not sustained at the later study visits (weeks 13 and 26). Bacterial community measures did not differ between the AZ and placebo groups.

CONCLUSIONS

This study provides further evidence that the mechanism for AZ's effect on clinical outcomes is not due solely to action on airway microbial composition.

Stability Considerations for Bacteriophages in Liquid Formulations Designed for Nebulization

Pulmonary bacterial infections present a significant health risk to those with chronic respiratory diseases (CRDs) including cystic fibrosis (CF) and chronic-obstructive pulmonary disease (COPD). With the emergence of antimicrobial resistance (AMR), novel therapeutics are desperately needed to combat the emergence of resistant superbugs. Phage therapy is one possible alternative or adjunct to current antibiotics with activity against antimicrobial-resistant pathogens. How phages are administered will depend on the site of infection. For respiratory infections, a number of factors must be considered to deliver active phages to sites deep within the lung. The inhalation of phages via nebulization is a promising method of delivery to distal lung sites; however, it has been shown to result in a loss of phage viability. Although preliminary studies have assessed the use of nebulization for phage therapy both in vitro and in vivo, the factors that determine phage stability during nebulized delivery have yet to be characterized. This review summarizes current findings on the formulation and stability of liquid phage formulations designed for nebulization, providing insights to maximize phage stability and bactericidal activity via this delivery method.

Lessons from the history of inorganic nanoparticles for inhalable diagnostics and therapeutics

The respiratory tract is one of the most accessible ones to exogenous nanoparticles, yet drug delivery by their means to it is made extraordinarily challenging because of the plexus of aerodynamic, hemodynamic and biomolecular factors at cellular and extracellular levels that synergistically define the safety and efficacy of this process. Here, the use of inorganic nanoparticles (INPs) for inhalable diagnostics and therapies of the lung is viewed through the prism of the history of studies on the interaction of INPs with the lower respiratory tract. The most conceptually and methodologically innovative and illuminative studies are referred to in the chronological order, as they were reported in the literature, and the trends in the progress of understanding this interaction of immense therapeutic and toxicological significance are being deduced from it. The most outstanding actual trends delineated include the diminishment of toxicity via surface functionalization, cell targeting, tagging and tracking via controlled binding and uptake, hybrid INP treatments, magnetic guidance, combined drug and gene delivery, use as adjuvants in inhalable vaccines, and other. Many of the understudied research directions, which have been accomplished by the nanostructured organic polymers in the pulmonary niche, are discussed. The progress in the use of INPs as inhalable diagnostics or therapeutics has been hampered by their well-recognized inflammatory potential and toxicity in the respiratory tract. However, the annual numbers of methodologically innovative studies have been on the rise throughout the past two decades, suggesting that this is a prolific direction of research, its comparatively poor commercial takings notwithstanding. Still, the lack of consensus on the effects of many INP compositions at low but therapeutically effective doses, the plethora of contradictory reports on ostensibly identical chemical compositions and NP properties, and the many cases of antagonism in combinatorial NP treatments imply that the rational design of inhalable medical devices based on INPs must rely on qualitative principles for the most part and embrace a partially stochastic approach as well. At the same time, the fact that the most studied INPs for pulmonary applications have been those with some of the thickest records of pulmonary toxicity, e.g., carbon, silver, gold, silica and iron oxide, is a silent call for the expansion of the search for new inorganic compositions for use in inhalable therapies to new territories.

Antimicrobial Strategies for Cystic Fibrosis

Lung infection is the leading cause of death in cystic fibrosis (CF), and antimicrobial therapies are the backbone of infection management. While many different strategies may be applied, rigorous microbiological surveillance, intensive eradication therapy, and long-term maintenance therapy based on inhaled antibiotics may be considered the main strategy for infection control in individuals with CF. While most of the existing evidence is based on infection with Pseudomonas aeruginosa, other important pathogens causing lung inflammation and deterioration exist and should be treated despite the evidence gap. In this chapter, we describe the approaches to the antimicrobial treatment of the most important pathogens in CF and the evidence behind.

Diagnosing Cystic Fibrosis in Adults

Diagnosing cystic fibrosis (CF) in adulthood is not a rare occurrence for CF centers despite the popular belief that the diagnosis is achieved almost universally in childhood by means of newborn screening or early clinical presentation. The purpose of this review article is to highlight specific considerations of adult diagnosis of CF. Obtaining a diagnosis of CF at any age is exceptionally important to ensure optimal treatment, monitoring, and support. In the new era of more personalized treatment with the advent of transformative therapies targeting the underlying protein defect, accurate diagnosis is of increasing importance. This review highlights the diagnostic algorithm leading to a new diagnosis of CF in adults. The diagnosis is usually confirmed in the presence of a compatible clinical presentation, evidence of cystic fibrosis transmembrane conductance regulator (CFTR) protein dysfunction, and/or identification of variants in the CFTR gene believed to alter protein function. Achieving the diagnosis, however, is not always straightforward as CFTR protein function exists on a continuum with different organs displaying varying sensitivity to diminution in function. We highlight the current knowledge regarding the epidemiology of CF diagnosed in adults and outline the various clinical presentations, including pulmonary and extrapulmonary, which are more common in this population. We expand on the stepwise testing procedures that lead to diagnosis, paying particular attention to additional levels of testing which may be required to achieve an accurate diagnosis. There continues to be an important need for both pulmonary and other specialists to be aware of the potential for later presentation of CF, as the improvements in treatment over decades have had large positive impacts on prognosis for people with this condition.

Anti-Pseudomonas aeruginosa Vaccines and Therapies: An Assessment of Clinical Trials

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes high morbidity and mortality in cystic fibrosis (CF) and immunocompromised patients, including patients with ventilator-associated pneumonia (VAP), severely burned patients, and patients with surgical wounds. Due to the intrinsic and extrinsic antibiotic resistance mechanisms, the ability to produce several cell-associated and extracellular virulence factors, and the capacity to adapt to several environmental conditions, eradicating P. aeruginosa within infected patients is difficult. Pseudomonas aeruginosa is one of the six multi-drug-resistant pathogens (ESKAPE) considered by the World Health Organization (WHO) as an entire group for which the development of novel antibiotics is urgently needed. In the United States (US) and within the last several years, P. aeruginosa caused 27% of deaths and approximately USD 767 million annually in health-care costs. Several P. aeruginosa therapies, including new antimicrobial agents, derivatives of existing antibiotics, novel antimicrobial agents such as bacteriophages and their chelators, potential vaccines targeting specific virulence factors, and immunotherapies have been developed. Within the last 2-3 decades, the efficacy of these different treatments was tested in clinical and preclinical trials. Despite these trials, no P. aeruginosa treatment is currently approved or available. In this review, we examined several of these clinicals, specifically those designed to combat P. aeruginosa infections in CF patients, patients with P. aeruginosa VAP, and P. aeruginosa-infected burn patients.

Development of nintedanib nanosuspension for inhaled treatment of experimental silicosis

Silicosis is an irreversible and progressive fibrotic lung disease caused by massive inhalation of crystalline silica dust at workplaces, affecting millions of industrial workers worldwide. A tyrosine kinase inhibitor, nintedanib (NTB), has emerged as a potential silicosis treatment due to its inhibitory effects on key signaling pathways that promote silica-induced pulmonary fibrosis. However, chronic and frequent use of the oral NTB formulation clinically approved for treating other fibrotic lung diseases often results in significant side effects. To this end, we engineered a nanocrystal-based suspension formulation of NTB (NTB-NS) possessing specific physicochemical properties to enhance drug retention in the lung for localized treatment of silicosis via inhalation. Our NTB-NS formulation was prepared using a wet-milling procedure in presence of Pluronic F127 to endow the formulation with nonadhesive surface coatings to minimize interactions with therapy-inactivating delivery barriers in the lung. We found that NTB-NS, following intratracheal administration, provided robust anti-fibrotic effects and mechanical lung function recovery in a mouse model of silicosis, whereas a 100-fold greater oral NTB dose given with a triple dosing frequency failed to do so. Importantly, several key pathological phenotypes were fully normalized by NTB-NS without displaying notable local or systemic adverse effects. Overall, NTB-NS may open a new avenue for localized treatment of silicosis and potentially other fibrotic lung diseases.

Incidence and associated risk factors for systemic drug levels with inhaled aminoglycoside therapy

OBJECTIVES

To characterize the incidence of and risk factors for a detectable drug level (DDL) in patients that received inhaled aminoglycoside therapy.

METHODS

This retrospective, single-centre study included adult patients who received at least one dose of an inhaled aminoglycoside with a drug level during inpatient hospitalization. Patients were excluded if they received an aminoglycoside intravenously within 7 days or if the drug level was not drawn within 4 h of the next dose. A repeated measures logistic regression model evaluated the association between potential risk factors and a DDL.

RESULTS

Among 286 drug levels, 88 (30.8%) drug levels were detectable. In multivariable analysis, cystic fibrosis (CF) (OR: 3.03; 95% CI: 1.10-8.35), chronic kidney disease (CKD) (OR: 4.25; 95% CI: 1.84-9.83), lung transplant recipient (OR: 3.08; 95% CI: 1.09-8.73), mechanical ventilation (OR: 2.99; 95% CI: 1.25-7.15) and tobramycin (OR: 5.26; 95% CI: 2.35-11.78) were associated with higher odds of a DDL. Among those with a DDL, inhaled aminoglycoside type and drug level concentration were not associated with acute kidney injury (P = 0.161).

CONCLUSIONS

Among 286 drug levels identified among inpatients receiving inhaled aminoglycoside therapy, 88 (30.8%) unique drug levels were detectable. Based on the results of this study, periodic trough concentrations should be considered for patients receiving inhaled aminoglycoside therapy with CF, CKD, lung transplantation, mechanical ventilation or tobramycin.

Role of inhaled antibiotics in the era of highly effective CFTR modulators

Recurrent and chronic bacterial infections are common in people with cystic fibrosis (CF) and contribute to lung function decline. Antibiotics are the mainstay in the treatment of exacerbations and chronic bacterial infection in CF. Inhaled antibiotics are effective in treating chronic respiratory bacterial infections and eradicating Pseudomonas aeruginosa from the respiratory tract, with limited systemic adverse effects. In the past decade, highly effective cystic fibrosis transmembrane conductance regulator (CFTR) modulators have become a new therapy that partially corrects/opens chloride transport in patients with selected CFTR mutations, restoring mucus hydration and improving mucociliary clearance. The recent triple CFTR modulator combination is approved for ∼80-90% of the CF population and significantly reduces pulmonary exacerbations and improves respiratory symptoms and lung function. CFTR modulators have shifted the focus from symptomatic treatment to personalised/precision medicine by targeting genotype-specific CFTR defects. While these are highly effective, they do not fully normalise lung physiology, stop inflammation or resolve chronic lung damage, such as bronchiectasis. The impact of these new drugs on lung health is likely to change the future management of chronic pulmonary infections in people with CF. This article reviews the role of inhaled antibiotics in the era of CFTR modulators.

Pseudomonas aeruginosa: Infections, Animal Modeling, and Therapeutics

Pseudomonas aeruginosa is an important Gram-negative opportunistic pathogen which causes many severe acute and chronic infections with high morbidity, and mortality rates as high as 40%. What makes P. aeruginosa a particularly challenging pathogen is its high intrinsic and acquired resistance to many of the available antibiotics. In this review, we review the important acute and chronic infections caused by this pathogen. We next discuss various animal models which have been developed to evaluate P. aeruginosa pathogenesis and assess therapeutics against this pathogen. Next, we review current treatments (antibiotics and vaccines) and provide an overview of their efficacies and their limitations. Finally, we highlight exciting literature on novel antibiotic-free strategies to control P. aeruginosa infections.

Inhaled anti-pseudomonal antibiotics for long-term therapy in cystic fibrosis

BACKGROUND

Inhaled antibiotics are commonly used to treat persistent airway infection with Pseudomonas aeruginosa that contributes to lung damage in people with cystic fibrosis. Current guidelines recommend inhaled tobramycin for individuals with cystic fibrosis and persistent Pseudomonas aeruginosa infection who are aged six years or older. The aim is to reduce bacterial load in the lungs so as to reduce inflammation and deterioration of lung function. This is an update of a previously published review.

OBJECTIVES

To evaluate the effects of long-term inhaled antibiotic therapy in people with cystic fibrosis on clinical outcomes (lung function, frequency of exacerbations and nutrition), quality of life and adverse events (including drug-sensitivity reactions and survival).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched ongoing trials registries. Date of last search: 28 June 2022.

SELECTION CRITERIA

We selected trials where people with cystic fibrosis received inhaled anti-pseudomonal antibiotic treatment for at least three months, treatment allocation was randomised or quasi-randomised, and there was a control group (either placebo, no placebo or another inhaled antibiotic).

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, judged the risk of bias, extracted data from these trials and judged the certainty of the evidence using the GRADE system.

MAIN RESULTS

The searches identified 410 citations to 125 trials; 18 trials (3042 participants aged between five and 45 years) met the inclusion criteria. Limited data were available for meta-analyses due to the variability of trial design and reporting of results. A total of 11 trials (1130 participants) compared an inhaled antibiotic to placebo or usual treatment for a duration between three and 33 months. Five trials (1255 participants) compared different antibiotics, two trials (585 participants) compared different regimens of tobramycin and one trial (90 participants) compared intermittent tobramycin with continuous tobramycin alternating with aztreonam. One trial (18 participants) compared an antibiotic to placebo and also to a different antibiotic and so fell into both groups. The most commonly studied antibiotic was tobramycin which was studied in 12 trials. Inhaled antibiotics compared to placebo We found that inhaled antibiotics may improve lung function measured in a variety of ways (4 trials, 814 participants). Compared to placebo, inhaled antibiotics may also reduce the frequency of exacerbations (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.47 to 0.93; 3 trials, 946 participants; low-certainty evidence). Inhaled antibiotics may lead to fewer days off school or work (quality of life measure) (mean difference (MD) -5.30 days, 95% CI -8.59 to -2.01; 1 trial, 245 participants; low-certainty evidence). There were insufficient data for us to be able to report an effect on nutritional outcomes and there was no effect on survival. There was no effect on antibiotic resistance seen in the two trials that were included in meta-analyses. We are uncertain of the effect of the intervention on adverse events (very low-certainty evidence), but tinnitus and voice alteration were the only events occurring more often in the inhaled antibiotics group. The overall certainty of evidence was deemed to be low for most outcomes due to risk of bias within the trials and imprecision due to low event rates. Different antibiotics or regimens compared Of the eight trials comparing different inhaled antibiotics or different antibiotic regimens, there was only one trial for each unique comparison. We found no differences between groups for any outcomes except for the following. Aztreonam lysine for inhalation probably improved forced expiratory volume at one second (FEV1) % predicted compared to tobramycin (MD -3.40%, 95% CI -6.63 to -0.17; 1 trial, 273 participants; moderate-certainty evidence). However, the method of defining the endpoint was different to the remaining trials and the participants were exposed to tobramycin for a long period making interpretation of the results problematic. We found no differences in any measure of lung function in the remaining comparisons. Trials measured pulmonary exacerbations in different ways and showed no differences between groups except for aztreonam lysine probably leading to fewer people needing treatment with additional antibiotics than with tobramycin (RR 0.66, 95% CI 0.51 to 0.86; 1 trial, 273 participants; moderate-certainty evidence); and there were fewer hospitalisations due to respiratory exacerbations with levofloxacin compared to tobramycin (RR 0.62, 95% CI 0.40 to 0.98; 1 trial, 282 participants; high-certainty evidence). Important treatment-related adverse events were not very common across comparisons, but were reported less often in the tobramycin group compared to both aztreonam lysine and colistimethate. We found the certainty of evidence for these comparisons to be directly related to the risk of bias within the individual trials and varied from low to high.

AUTHORS' CONCLUSIONS

Long-term treatment with inhaled anti-pseudomonal antibiotics probably improves lung function and reduces exacerbation rates, but pooled estimates of the level of benefit were very limited. The best evidence available is for inhaled tobramycin. More evidence from trials measuring similar outcomes in the same way is needed to determine a better measure of benefit. Longer-term trials are needed to look at the effect of inhaled antibiotics on quality of life, survival and nutritional outcomes.

Inhaled antibiotics for pulmonary exacerbations in cystic fibrosis

BACKGROUND

Cystic fibrosis is a genetic disorder in which abnormal mucus in the lungs is associated with susceptibility to persistent infection. Pulmonary exacerbations are when symptoms of infection become more severe. Antibiotics are an essential part of treatment for exacerbations and inhaled antibiotics may be used alone or in conjunction with oral antibiotics for milder exacerbations or with intravenous antibiotics for more severe infections. Inhaled antibiotics do not cause the same adverse effects as intravenous antibiotics and may prove an alternative in people with poor access to their veins. This is an update of a previously published review.

OBJECTIVES

To determine if treatment of pulmonary exacerbations with inhaled antibiotics in people with cystic fibrosis improves their quality of life, reduces time off school or work, and improves their long-term lung function.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Group's Cystic Fibrosis Trials Register. Date of the last search: 7 March 2022. We also searched ClinicalTrials.gov, the Australia and New Zealand Clinical Trials Registry and WHO ICTRP for relevant trials. Date of last search: 3 May 2022.

SELECTION CRITERIA

Randomised controlled trials in people with cystic fibrosis with a pulmonary exacerbation in whom treatment with inhaled antibiotics was compared to placebo, standard treatment or another inhaled antibiotic for between one and four weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected eligible trials, assessed the risk of bias in each trial and extracted data. They assessed the certainty of the evidence using the GRADE criteria. Authors of the included trials were contacted for more information.

MAIN RESULTS

Five trials with 183 participants are included in the review. Two trials (77 participants) compared inhaled antibiotics alone to intravenous antibiotics alone and three trials (106 participants) compared a combination of inhaled and intravenous antibiotics to intravenous antibiotics alone. Trials were heterogenous in design and two were only available in abstract form. Risk of bias was difficult to assess in most trials but, for four out of five trials, we judged there to be a high risk from lack of blinding and an unclear risk with regards to randomisation. Results were not fully reported and only limited data were available for analysis. One trial was a cross-over design and we only included data from the first intervention arm. Inhaled antibiotics alone versus intravenous antibiotics alone Only one trial (18 participants) reported a perceived improvement in lifestyle (quality of life) in both groups (very low-certainty evidence). Neither trial reported on time off work or school. Both trials measured lung function, but there was no difference reported between treatment groups (very low-certainty evidence). With regards to our secondary outcomes, one trial (18 participants) reported no difference in the need for additional antibiotics and the second trial (59 participants) reported on the time to next exacerbation. In neither case was a difference between treatments identified (both very low-certainty evidence). The single trial (18 participants) measuring adverse events and sputum microbiology did not observe any in either treatment group for either outcome (very low-certainty  evidence). Inhaled antibiotics plus intravenous antibiotics versus intravenous antibiotics alone Inhaled antibiotics plus intravenous antibiotics may make little or no difference to quality of life compared to intravenous antibiotics alone. None of the trials reported time off work or school. All three trials measured lung function, but found no difference between groups in forced expiratory volume in one second (two trials; 44 participants; very low-certainty evidence) or vital capacity (one trial; 62 participants). None of the trials reported on the need for additional antibiotics. Inhaled plus intravenous antibiotics may make little difference to the time to next exacerbation; however, one trial (28 participants) reported on hospital admissions and found no difference between groups. There is likely no difference between groups in adverse events (very low-certainty evidence) and one trial (62 participants) reported no difference in the emergence of antibiotic-resistant organisms (very low-certainty evidence).

AUTHORS' CONCLUSIONS

We identified only low- or very low-certainty evidence to judge the effectiveness of inhaled antibiotics for the treatment of pulmonary exacerbations in people with cystic fibrosis. The included trials were not sufficiently powered to achieve their goals. Hence, we are unable to demonstrate whether one treatment was superior to the other or not. Further research is needed to establish whether inhaled tobramycin may be used as an alternative to intravenous tobramycin for some pulmonary exacerbations.

Aerosol therapy during mechanical ventilation in intensive care units: A questionnaire-based survey of 2203 ICU medical staff in China

Background

To describe the current status of aerosol therapy during mechanical ventilation (MV) and the practice, knowledge, and beliefs about aerosol therapy in physicians working in the intensive care unit (ICU) in China.

Methods

A physician self-administered questionnaire-based cross-sectional survey was carried out from January 2019 to July 2019. An electronic questionnaire was designed, and physicians who worked regularly in ICUs across several hospitals were contacted through WeChat. Answers to all questions and the general characteristics of physicians who answered the questionnaire were collected and analyzed.

Results

A total of 2203 medical staff who regularly worked in the ICUs completed this questionnaire (9.0% missing data); 87.7% of the participants were doctors. Most respondents claimed that they often administered aerosolization therapy. Ultrasonic atomizer (50.7%) and jet nebulizer (48.6%) were the most commonly used atomization devices. Bronchodilators (65.8%) and steroids (66.3%) were the most frequently aerosolized drugs during MV. During nebulization, ventilator settings were never changed by 32.7% of respondents. Only 49.1% of respondents knew the appropriate place for a nebulizer. Further, 62.7% of respondents using heated humidifiers reported turning them off during nebulization. Specific knowledge about droplet size and nebulization yield was poor. Respondents from tertiary hospitals and those with higher technical title or work experience tended to have better accuracy than those from primary hospitals or with lower technical titles (P < 0.050).

Conclusions

Aerosol therapy was commonly used during MV, and the most frequent drugs were bronchodilators and steroids. Scientific knowledge about the optimal implementation of aerosol therapy during MV seemed deficient.

Gram-negative bacteria act as a reservoir for aminoglycoside antibiotics that interact with host factors to enhance bacterial killing in a mouse model of pneumonia

In vitro exposure of multiple Gram-negative bacteria to an aminoglycoside (AG) antibiotic has previously been demonstrated to result in bacterial alterations that interact with host factors to suppress Gram-negative pneumonia. However, the mechanisms resulting in suppression are not known. Here, the hypothesis that Gram-negative bacteria bind and retain AGs, which are introduced into the lung and interact with host defenses to affect bacterial killing, was tested. Following in vitro exposure of one of several, pathogenic Gram-negative bacteria to the AG antibiotics kanamycin or gentamicin, AGs were detected in bacterial cell pellets (up to 208 μg/mL). Using inhibitors of AG binding and internalization, the bacterial outer membrane was implicated as the predominant kanamycin and gentamicin reservoir. Following intranasal administration of gentamicin-bound bacteria or gentamicin solution at the time of infection with live, AG-naïve bacteria, gentamicin was detected in the lungs of infected mice (up to 8 μg/g). Co-inoculation with gentamicin-bound bacteria resulted in killing of AG-naïve bacteria by up to 3-log₁₀, mirroring the effects of intranasal gentamicin treatment. In vitro killing of AG-naïve bacteria mediated by kanamycin-bound bacteria required the presence of detergents or pulmonary surfactant, suggesting that increased bacterial killing inside the murine lung is facilitated by the detergent component of pulmonary surfactant. These findings demonstrate that Gram-negative bacteria bind and retain AGs that can interact with host-derived pulmonary surfactant to enhance bacterial killing in the lung. This may help explain why AGs appear to have unique efficacy in the lung and might expand their clinical utility.

Increasing life expectancy in cystic fibrosis: Advances and challenges

Since the first description of cystic fibrosis in 1938, there have been significant advances in both quality of life and longevity for people living with this disease. In this article we describe the milestones of the last 80 years and what we perceive to be the remaining barriers to normalcy for this population.

Effects of long-term tobramycin inhalation solution (TIS) once daily on exacerbation rate in patients with non-cystic fibrosis bronchiectasis

BACKGROUND

Use of long-term tobramycin inhalation solution (TIS) has been shown beneficial in cystic fibrosis (CF) and earlier findings also suggest a benefit in non-CF bronchiectasis. We investigated the efficacy and safety of maintenance TIS once daily (OD) in frequent exacerbating bronchiectasis patients chronically infected by different pathogens sensitive for tobramycin.

OBJECTIVE

The primary outcome was the frequency of exacerbations during the 12-month study period. Secondary outcomes were time to first exacerbation, change in lung function and quality of life (QoL), bacterial analysis and safety.

MATERIALS/PATIENTS

IN THIS MULTICENTER RCT PATIENTS AGED ≥ 18-YEAR-OLD WERE INCLUDED WITH CONFIRMED BRONCHIECTASIS AND ≥ 2 EXACERBATIONS IN THE PRECEDING YEAR. PATIENTS WERE ASSIGNED (1:1) TO RECEIVE TIS OR PLACEBO OD FOR 1-YEAR.: RESULTS: 58 patients were included of which 52 were analyzed in the mITT analysis. TIS reduced exacerbation frequency with a RR of 0.74 (95% CI 0.49-1.14) (p = 0.15). Within the TIS population a decrease in number of exacerbations was found (2; p = 0.00), which was also seen in the placebo-treated patients (1.5; p = 0.00). In the TIS-treated patients the QoL improved (LRTI-VAS p = 0.02 Leicester Cough p = 0.02) without additional safety concerns. No differences were found for the other secondary outcomes.

CONCLUSION

Long-term TIS OD is a safe treatment modality and showed a non-significant reduced exacerbation frequency of 0.74 as compared to placebo in bronchiectasis patients chronically infected by tobramycin sensitive pathogens. TIS OD may be a potential therapeutic strategy in selected patients with bronchiectasis suffering from a high burden of disease.

TRAIL REGISTRATION NUMBER

The BATTLE study was registered at Clinical trials.gov number: NCT02657473 . Date: 13 august 2016.

Effect of Concomitant Azithromycin and Tobramycin Use on Cystic Fibrosis Pulmonary Exacerbation Treatment

Rationale: Pulmonary exacerbations (PExs) are associated with significant morbidity in people with cystic fibrosis (CF). Severe PExs are treated with intravenous antibiotics, including tobramycin. CF care guidelines recommend continuing chronic maintenance medications during PEx treatment. Azithromycin (AZM) is one of the most widely prescribed chronic medications for CF in the United States. Recent evidence has identified a potential antagonistic relationship between AZM and tobramycin.Objectives: To determine whether, among PEx treated with intravenous tobramycin, concomitant AZM use is associated with worse clinical outcomes.Methods: Retrospective cohort study using the CF Foundation Patient Registry-Pediatric Health Information System (CFFPR-PHIS)-linked dataset. People with CF age 6-21 years were included if they were hospitalized between 2006 and 2016 for a PEx. Inverse probability of treatment weighing was used to minimize the effects of confounders, including indication bias. Associations of concomitant treatment with AZM and lung function outcomes were determined using linear mixed-effect models and generalized estimating equations. Cox proportional hazard regression models were used to evaluate associations with time to next PEx.Results: Among the 10,660 people with CF included in the CFFPR-PHIS-linked dataset, 2,294 children and adolescents with 5,022 PExs that had intravenous tobramycin use were identified. A little less than half (n = 2,247; 45%) of all PExs were treated concomitantly with AZM and intravenous tobramycin. AZM use both at the most recent outpatient clinic encounter and during PEx treatment in combination with intravenous tobramycin was associated with a significantly lower absolute improvement in percentage-predicted forced expiratory volume in 1 second (ppFEV₁) (-0.93%; 95% confidence interval [CI], -1.78 to -0.07; P = 0.033), a lesser odds of returning to 90% or more of baseline ppFEV₁ (odds ratio, 0.79; 95% CI, 0.68-0.93; P = 0.003), and a shorter time to next PEx requiring intravenous antibiotics (hazard ratio, 1.22; 95% CI, 1.14-1.31; P < 0.001) compared with intravenous tobramycin use without concomitant AZM.Conclusions: Concomitant AZM and intravenous tobramycin use for in-hospital PEx treatment was associated with poorer clinical outcomes than treatment with intravenous tobramycin without AZM. These results support the hypothesis that an antagonistic relationship between these two medications might exist.

Therapeutic Approach of Chronic Pseudomonas Infection in Cystic Fibrosis-A Network Meta-Analysis

Pseudomonas infection is a major determinant of morbidity and mortality in cystic fibrosis (CF). Maintaining optimal lung function in CF patients carrying Pseudomonas remains a challenge. Our study aims to investigate the efficacy of antipseudomonal inhaled antibiotics in CF patients with chronic Pseudomonas infection. A Bayesian network meta-analysis of randomized controlled trials was conducted. The main outcomes were changes in: (a) forced respiratory volume (FEV1), (b) Pseudomonas aeruginosa sputum density, and (c) CF Questionnaire Revised Respiratory Symptom Score (CFQR-RSS) at 4 weeks follow-up. Eighteen trials which reported on treatment with aztreonam lysine, tobramycin, colistin, levofloxacin, fosfomycin/tobramycin, and amikacin in various dosages were eligible for inclusion. In terms of change in FEV1%, aztreonam lysine (t.i.d., 75 mg) with a 28-day run in the tobramycin phase, aztreonam lysine (b.i.d., 75 mg) with a 28-day run in the tobramycin phase had the highest probability of being the most effective treatment (SUCRAs were 77, 76%, respectively). Regarding change in Pseudomonas sputum density, aztreonam lysine (b.i.d., 75 mg) with a 28-day run in the tobramycin phase, aztreonam lysine (t.i.d., 75 mg) with a 28-day run in the tobramycin phase had the highest probability of being the most effective treatment (SUCRAs were 90, 86%, respectively). Regarding change in CFQR-RSS, aztreonam lysine (t.i.d., 75 mg) and aztreonam lysine (b.i.d., 75 mg) with a 28-day run in the tobramycin inhalation solution phase had the highest probability of being the most effective treatments (SUCRA:74% and 72%, respectively). Regarding changes in FEV1% and Pseudomonas sputum density, aztreonam lysine with a run in tobramycin phase may be the best treatment option in treating chronic Pseudomonas in CF. According to CFQR-RSS no significant differences were found. Given the limitations of the studies included, validation trials are called for.

Assessment of treatment burden and complexity in cystic fibrosis: A quality improvement project

BACKGROUND

Treatment regimens for cystic fibrosis (CF) continue to evolve and grow in complexity. Treatment regimen burden, and associated sequelae, are incompletely understood.

OBJECTIVE

Quality improvement (QI) methods were used to investigate treatment burden of CF care, family and care team partnerships, and potential interventions to reduce burden.

METHODS

Patients 6-24 years with CF and caregivers of patients 6-13 years were surveyed. Portions of validated tools and existing surveys measured burden and family-care team partnership. An automated report calculated treatment complexity. Plan-do-study-act cycles tested survey administration during CF visits and run charts tracked progress. Interventions to reduce burden were tracked, and bidirectional assessments explored partnerships among patients, families and clinicians.

RESULTS

Over 6 months, 110 patients and 62 caregivers completed assessments. Caregivers reported lower burden/higher quality of life (74.0, range 22.2-100) than patients (66.5, range 16.7-100). The mean treatment complexity score was 17.2 (range 6-34). Treatment complexity and burden increased with patient age (p < .05 and p < .01 respectively). Lower lung function correlated with higher patient-reported burden (p < .01) and higher treatment complexity (p < .0001). As burden increased, providers more often performed select interventions (discussed combining treatments, simplified regimens, or involved other team members (p < .05 for each)). Families reported high partnership (mean scores 4.7-4.8, 5 = high), and providers reported high utilization of partnership tools (tool used in 77% of encounters).

CONCLUSION

We assessed, quantified, and responded to treatment burden and complexity in real-time during outpatient CF visits. Systematic and individualized assessments of treatment complexity and burden may enhance treatment adherence while preserving quality of life.

Status of inhalable antimicrobial agents for lung infection: progress and prospects

Introduction: Available parenteral and oral administration of antimicrobial agents (AMAs) in respiratory infections often show less penetration into the lung parenchyma. Due to inappropriate dose availability, the rate of antibiotic resistance is increasing gradually. Inhaled antibiotics intensely improve the availability of drugs at the site of respiratory infections. This targeted delivery minimizes systemic exposure and associated toxicity.Area covers: This review was performed by searching in the scientific database like PubMed and several trusted government sites like fda.gov, cdc.gov, ClinicalTrials.gov, etc. For better understanding, AMAs are classified in different stages of approval. Mechanism and characterization of pulmonary drug deposition section helps to understand the effective delivery of AMAs to the respiratory tract. There is a need for proper adoption of delivery devices for inhalable AMAs. Thus, delivery devices are extensively explained. Inspiratory flow has a remarkable impact on the delivery device that has been explained in detail.Expert opinion: Pulmonary delivery restricts the bulk administration of drugs in comparison with other routes. Therefore, novel AMAs with higher bactericidal activity at lower concentrations need to be synthesized. Extensive research is indeed in developing innovative delivery devices that would able to deliver higher doses of AMAs through the pulmonary route.

Update on Respiratory Fungal Infections in Cystic Fibrosis Lung Disease and after Lung Transplantation

Cystic fibrosis is the most common autosomal-recessive metabolic disease in the Western world. Impaired trans-membrane chloride transport via the cystic fibrosis transmembrane conductance regulator (CFTR) protein causes thickened body fluids. In the respiratory system, this leads to chronic suppurative cough and recurrent pulmonary infective exacerbations, resulting in progressive lung damage and respiratory failure. Whilst the impact of bacterial infections on CF lung disease has long been recognized, our understanding of pulmonary mycosis is less clear. The range and detection rates of fungal taxa isolated from CF airway samples are expanding, however, in the absence of consensus criteria and univocal treatment protocols for most respiratory fungal conditions, interpretation of laboratory reports and the decision to treat remain challenging. In this review, we give an overview on fungal airway infections in CF and CF-lung transplant recipients and focus on the most common fungal taxa detected in CF, Aspergillus fumigatus, Candida spp., Scedosporium apiospermum complex, Lomentospora species, and Exophiala dermatitidis, their clinical presentations, common treatments and prophylactic strategies, and clinical challenges from a physician’s point of view.

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.

Sputum microbiota in adults with CF associates with response to inhaled tobramycin

BACKGROUND

Inhaled tobramycin powder/solution (TIP/S) use has resulted in improved clinical outcomes in patients with cystic fibrosis (CF) with chronic Pseudomonas aeruginosa. However, TIP/S effect on the CF sputum microbiome has not been explored. We hypothesised that TIP/S has additional 'off-target' effects beyond merely P. aeruginosa and that baseline microbiome prior to initiation of therapy is associated with subsequent patient response.

METHODS

We drew sputum samples from a prospectively collected biobank. Patients were included if they had one sputum sample in the 18 months before and after TIP/S. Bacterial 16S rRNA gene profiling was used to characterise the sputum microbiome.

RESULTS

Forty-one patients met our inclusion criteria and 151 sputum samples were assessed. At baseline, median age was 30.4 years (IQR 24.2-35.2) and forced expiratory volume in 1 (FEV₁) second was 57% predicted (IQR 44-74). Nineteen patients were defined a priori as responders having no net decrease in FEV₁ in the year following TIP/S. No significant changes were observed in key microbiome metrics of alpha (within-sample) or beta (between-sample) diversity for samples collected before and after TIP/S. However, significant beta-diversity (Bray-Curtis) differences were noted at baseline between patients based on response status. Notably, responders were observed to have a higher abundance of Staphylococcus in pretherapy baseline samples.

CONCLUSIONS

Our longitudinal study demonstrates that the sputum microbiome of patients with CF is relatively stable following inhaled tobramycin over many months. Intriguingly, our findings suggest that baseline microbiome may associate with patient response to TIP/S-suggesting the sputum microbiome could be used to personalise therapy.

Cystic fibrosis - Ten promising therapeutic approaches in the current era of care

INTRODUCTION

Cystic fibrosis (CF) is a genetic disease affecting multiple organ systems. Research and innovations in novel therapeutic agents and health care delivery have resulted in dramatic improvements in quality of life and survival for people with CF. Despite this, significant disease burden persists for many and this is compounded by disparities in treatment access and care which globally necessitates further work to improve outcomes. Because of the advent of numerous therapies which include gene-targeted modulators in parallel with specialized care delivery models, innovative efforts continue.

AREAS COVERED

In this review, we discuss the available data on investigational agents in clinical development and currently available treatments for CF. We also evaluate approaches to care delivery, consider treatment gaps, and propose future directions for advancement.

EXPERT OPINION

Since the discovery of the CF gene, CFTR modulators have provided a hallmark of success, even though it was thought not previously possible. This has led to reinvigorated efforts and innovations in treatment approaches and care delivery. Numerous challenges remain because of genetic and phenotypic heterogeneity, access issues, and therapeutic costs, but the collaborative approach between stakeholders for continued innovation fuels optimism. Abbreviations: CF cystic fibrosis; CFF Cystic Fibrosis Foundation (USA); CFTR cystic fibrosis transmembrane regulator; CRISPR clustered regularly interspaced short palindromic repeats; COX cyclo oxygenase; FDA US Food and Drug Administration; FEV1% forced expiratory volume in one second % predicted; F508del deletion of phenylalanine (F) in the 508th position (most common mutation); G551D substitution of the amino acid glycine by aspartate at position 551 in the nucleotide binding domain-1 of the CFTR gene; LMIC low- and middle-income country; LTB4 leukotriene B4; MDT multi-disciplinary care team; NO nitric oxide; NSAIDs non-steroidal anti-inflammatory drugs; SLPI secretory leukocyte protease inhibitor.

Efficacy and safety of TOBI Podhaler in Pseudomonas aeruginosa-infected bronchiectasis patients: iBEST study

The study aimed to determine the efficacy of a safe and well-tolerated dose and regimen of tobramycin inhalation powder (TIP) on Pseudomonas aeruginosa sputum density in patients with bronchiectasis.

This is a phase II, double-blind, randomised study in bronchiectasis patients aged ≥18 years with chronic P. aeruginosa infection. Patients were randomised 1:1:1 to either cohort A: three capsules of TIP once daily (84 mg); cohort B: five capsules once daily (140 mg) or cohort C: four capsules twice daily (224 mg). Within each cohort, patients were further randomised 2:2:1 either to TIP continuously, TIP cyclically (alternating 28 days of TIP and placebo) or placebo for 16 weeks, respectively and were followed up for 8 weeks.

Overall, 107 patients were randomised to cohorts A (n=34), B (n=36) and C (n=37). All three TIP doses significantly reduced the P. aeruginosa sputum density from baseline to day 29 versus placebo in a dose-dependent manner (p≤0.0001, each). A smaller proportion of patients in the continuous-TIP (34.1%) and cyclical-TIP (35.7%) groups experienced pulmonary exacerbations versus placebo (47.6%) and also required fewer anti-pseudomonal antibiotics (38.6% on continuous TIP and 42.9% on cyclical TIP) versus placebo (57.1%) although not statistically significant. Pulmonary exacerbation of bronchiectasis was the most frequent (37.4%) adverse event. Overall, TIP was well tolerated, however, 23.4% of the patients discontinued the study drug due to adverse events.

Continuous- and cyclical-TIP regimens with all three doses were safe and effective in reducing the P. aeruginosa sputum density in patients with bronchiectasis and chronic P. aeruginosa infection.

Co-Amorphization of Kanamycin with Amino Acids Improves Aerosolization

Different formulation techniques have been investigated to prepare highly aerosolizable dry powders to deliver a high dose of antibiotics to the lung for treating local infections. In this study, we investigated the influence of the co-amorphization of a model drug, kanamycin, with selected amino acids (valine, methionine, phenylalanine, and tryptophan) by co-spray drying on its aerosolization. The co-amorphicity was confirmed by thermal technique. The physical stability was monitored using low-frequency Raman spectroscopy coupled with principal component analysis. Except for the kanamycin-valine formulation, all the formulations offered improved fine particle fraction (FPF) with the highest FPF of 84% achieved for the kanamycin-methionine formulation. All the co-amorphous formulations were physically stable for 28 days at low relative humidity (25 °C/<15% RH) and exhibited stable aerosolization. At higher RH (53%), even though methionine transformed into its crystalline counterpart, the kanamycin-methionine formulation offered the best aerosolization stability without any decrease in FPF. While further studies are warranted to reveal the underlying mechanism, this study reports that the co-amorphization of kanamycin with amino acids, especially with methionine, has the potential to be developed as a high dose kanamycin dry powder formulation.

Scope and limitations on aerosol drug delivery for the treatment of infectious respiratory diseases

The rise of antimicrobial resistance has created an urgent need for the development of new methods for antibiotics delivery to patients with pulmonary infections in order to mainly increase the effectiveness of the drugs administration, to minimize the risk of emergence of resistant strains, and to prevent patients reinfection. Since bacterial resistance is often related to antibiotic concentration, their pulmonary administration could eradicate strains resistant to the same drug at the concentration achieved through the systemic circulation. Pulmonary administration offers several advantages; it directly targets the site of the infection which allows the inhaled dose of the drug to be reduced compared to that administered orally or parenterally while keeping the same local effect. The review article is made with an objective to compile information about various existing modern technologies developed to provide greater patient compliance and reduce the undesirable side effect of the drugs. In conclusion, aerosol antibiotic delivery appears as one of the best technologies for the treatment of pulmonary infectious diseases and able to limit the systemic adverse effects related to the high drug dose and to make life easier for the patients.

Tobramycin Serum Concentrations in Tracheostomy-Dependent Children Receiving Inhaled Tobramycin

Introduction: In recent years, administration of inhaled aminoglycosides has gained popularity in tracheostomy-dependent pediatric patients because of medication delivery to the target site of action while minimizing systemic absorption and adverse effects. A recent report of detectable serum tobramycin concentrations in critically ill children receiving inhaled tobramycin 300 mg every 12 h prompted our investigation in tracheostomy-dependent pediatric patients receiving inhaled tobramycin 80 mg every 8 h. Methods: Serum tobramycin trough concentrations were obtained from tracheostomy-dependent pediatric patients receiving treatment with inhaled tobramycin 80 mg every 8 h for the treatment of tracheitis. Patient data, including demographic data, medical history, renal function, and serum concentrations, were collected. Results: Twelve patients with a median age of 0.5 (0.3-6.1) years had serum tobramycin concentrations evaluated. Eleven of the 12 patients had undetectable trough concentrations (<0.6 mcg/mL). All of these patients had normal blood urea nitrogen (BUN) and serum creatinine (SCr) for age and no history of kidney disease. One patient had a detectable trough concentration of 2.1 mcg/mL. This patient was 11 months old and had polycystic kidney disease with an elevated BUN and SCr for age. Conclusions: Detectable serum concentration from systemic absorption of inhaled tobramycin 80 mg every 8 h is unlikely in tracheostomy-dependent pediatric patients with normal renal function. However, in tracheostomy-dependent pediatric patients with a history of renal dysfunction or elevations in BUN or SCr, inhaled tobramycin should be used with caution. Monitoring serum concentrations to guide dose modification should be considered in these patients.

Gut Check Time: Antibiotic Delivery Strategies to Reduce Antimicrobial Resistance

Antimicrobial resistance (AMR) has developed into a huge threat to global health, and reducing it is an urgent priority for public health authorities. The importance of a healthy and balanced gut microbiome has been identified as a key protective factor against AMR development, but this can be significantly affected by antibiotic therapy, resulting in dysbiosis and reduction of taxonomic richness. The way in which antibiotics are administered could form an important part of future antimicrobial stewardship strategies, where drug delivery is ideally placed to play a key role in the fight against AMR. This review focuses on drug delivery strategies for antibiotic administration, including avoidance of the gut microbiome and targeted delivery approaches, which may reduce AMR.

Efficacy of inhaled ciprofloxacin agents for the treatment of bronchiectasis: a systematic review and meta-analysis of randomized controlled trials

Background:

The efficacy of inhaled ciprofloxacin agents in the treatment of patients with bronchiectasis is controversial. The objective of the study was to review systematically the efficacy of inhaled ciprofloxacin agents in patients with bronchiectasis.

Methods:

We searched PubMed, EMBASE, and Cochrane Library databases for randomized controlled trials (RCTs) evaluating inhaled ciprofloxacin agents among patients with bronchiectasis. Data were pooled using a meta-analysis technique.

Results:

Two phase II and four phase III RCTs were included with a total of 1685 patients. Treatment durations of phase III studies were 48 weeks, while those of phase II studies were shorter. Pooled analysis of overall studies exhibited a statistically significant benefit of inhaled ciprofloxacin agents in three exacerbation outcome measures, including time to first exacerbation (hazard ratio 0.74, 95% confidence interval [CI] 0.63–0.86, I² 23%), exacerbation frequency (risk ratio [RR] 0.73, 95% CI 0.61–0.86, I² 42%), and exacerbation proportion (RR 0.85, 95% CI 0.76–0.96, I² 25%) without significant heterogeneity. Outcomes evaluating pulmonary function, quality of life, and adverse events were not significantly different between the two groups. Although eradication of respiratory pathogens was more frequently observed, the emergence of ciprofloxacin resistance was also significantly higher in the ciprofloxacin group.

Conclusions:

A meta-analysis of RCTs of inhaled ciprofloxacin agents showed clinical benefit in terms of pulmonary exacerbations in patients with bronchiectasis. Since a significant increase of resistance was also noticed, clinical trials with a longer study period are required for a conclusive assessment.

The reviews of this paper are available via the supplemental material section.

Off-label use of intravenous antimicrobials for inhalation in patients with cystic fibrosis

Management of infections in patients with cystic fibrosis (CF) presents challenges for healthcare providers, including the eradication of initial acquisition, treatment of acute exacerbations, and chronic infection with suppressive therapy. Inhaled antimicrobial therapy for infections in patients with CF has been used in these capacities, often in an effort to achieve optimal concentrations in sputum for antimicrobial efficacy while mitigating potential toxicities associated with systemic therapy. Unfortunately, there are few commercially available products formulated for inhalation, resulting in the off-label use of other formulations, such as intravenous products, administered via nebulization. This review aims to examine the evidence supporting the efficacy of these off-label formulations for management of acute and chronic infections associated with CF, as well as adverse effects associated with their use.

Targeting airway inflammation in cystic fibrosis

Introduction: The major cause of morbidity and mortality in patients with cystic fibrosis (CF) is lung disease. Inflammation in the CF airways occurs from a young age and contributes significantly to disease progression and shortened life expectancy. Areas covered: In this review, we discuss the key immune cells involved in airway inflammation in CF, the contribution of the intrinsic genetic defect to the CF inflammatory phenotype, and anti-inflammatory strategies designed to overcome what is a critical factor in the pathogenesis of CF lung disease. Review of the literature was carried out using the MEDLINE (from 1975 to 2018), Google Scholar and The Cochrane Library databases. Expert opinion: Therapeutic interventions specifically targeting the defective CF transmembrane conductance regulator (CFTR) protein have changed the clinical landscape and significantly improved the outlook for CF. As survival estimates for people with CF increase, long-term management has become an important focus, with an increased need for therapies targeted at specific elements of inflammation, to complement CFTR modulator therapies.

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.

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

Optimizing outcomes of pulmonary exacerbations in cystic fibrosis

PURPOSE OF REVIEW

Pulmonary exacerbations are described as worsening of the daily symptoms of cystic fibrosis airways disease, typically with increased cough and sputum production. There are often associated signs such as weight loss and reduced lung function. These events occur frequently and are associated with considerable cost and morbidity. Although approved maintenance therapies are shown to reduce exacerbations, they still occur and are associated with poor outcomes despite treatment. Guidelines to define best practices found a paucity of evidence upon which to base recommendations.

RECENT FINDINGS

There are ongoing studies that are trying to build the evidence upon which to improve our practice. Antibiotics remain a core aspect of treatment, but there is high variance in practice patterns including selection of antibiotics and duration of therapy. In addition, there is a discordance between antibiotic susceptibility test results and clinical outcomes, suggesting we need better approaches to guide antibiotic selection.

SUMMARY

Treatment durations are highly variable but recent evidence has demonstrated worse outcomes with shorter durations; longer durations may be associated with complications of treatment, suggesting an optimal duration could be identified. New studies aim to define best practices to improve outcomes with treatment of pulmonary exacerbations.

Vestibulotoxicity in a patient without renal failure after inhaled tobramycin

Aminoglycoside antibiotics have a long history of use in the control of gram-negative bacterial infections, but their systemic use has been complicated by known ototoxicity and nephrotoxicity. Because of the utility of these medications in patients with frequent pulmonary infections, there has been a move towards the use of inhaled agents, in particular tobramycin, due to a lower rate of systemic complications. Inhaled tobramycin is generally consider to be safe from otologic complications, with only two previous reports of ototoxicity, both in patients who had underlying chronic renal disease. Here we present the first case of a patient developing isolated vestibular toxicity, without associated hearing loss or evidence of renal insufficiency, in a patient receiving inhaled tobramycin. This is an extremely rare complication of an inhaled aminoglycoside and underscores the importance of careful monitoring despite perceived safety.

Cystic fibrosis - an example of personalized and precision medicine

Cystic fibrosis (CF) is a severe, monogenic, autosomal recessive disease caused by mutations in the CFTR (cystic fibrosis transmembrane regulator) gene, where disturbed chloride and bicarbonate transportation in epithelial cells results in a multiorgan disease with primarily pulmonary infections and pancreatic insufficiency. In 1968, the Copenhagen CF Center was established, and centralized care of CF patients with monthly control was introduced. Close monitoring and treatment of Pseudomonas lung infection as well as segregation of patients with different infection status improved the clinical outcome as well as survival. Prophylactic basic treatment as well as infection treatments follow specific algorithms. A variety of comorbidities have all along the pulmonary infection control necessitated personalized care, adjusted to the patients' phenotype. With the introduction of CFTR modulators, the treatment has shifted from prophylactic, symptomatic type toward a new era of precision medicine targeting the basic defect according to the patients' CFTR genotype. Future directions will focus on further improvement of the CFTR modulators and gene therapy, as well as modifier genes and CF phenotype.

Tobramycin reduces key virulence determinants in the proteome of Pseudomonas aeruginosa outer membrane vesicles

Tobramycin is commonly used to treat Pseudomonas aeruginosa lung infections in patients with Cystic Fibrosis (CF). Tobramycin treatment leads to increased lung function and fewer clinical exacerbations in CF patients, and modestly reduces the density of P. aeruginosa in the lungs. P. aeruginosa resides primarily in the mucus overlying lung epithelial cells and secretes outer membrane vesicles (OMVs) that diffuse through the mucus and fuse with airway epithelial cells, thus delivering virulence factors into the cytoplasm that modify the innate immune response. The goal of this study was to test the hypothesis that Tobramycin reduces the abundance of virulence factors in OMVs secreted by P. aeruginosa. Characterization of the proteome of OMVs isolated from control or Tobramycin-exposed P. aeruginosa strain PAO1 revealed that Tobramycin reduced several OMV-associated virulence determinants, including AprA, an alkaline protease that enhances P. aeruginosa survival in the lung, and is predicted to contribute to the inhibitory effect of P. aeruginosa on Phe508del-CFTR Cl^- secretion by primary human bronchial epithelial cells. Deletion of the gene encoding AprA reduced the inhibitory effect of P. aeruginosa on Phe508del-CFTR Cl^- secretion. Moreover, as predicted by our proteomic analysis, OMVs isolated from Tobramycin treated P. aeruginosa had a diminished inhibitory effect on Phe508del-CFTR Cl^- secretion compared to OMVs isolated from control P. aeruginosa. Taken together, our proteomic analysis of OMVs and biological validation suggest that Tobramycin may improve lung function in CF patients infected with P. aeruginosa by reducing several key virulence factors in OMVs that reduce CFTR Cl^- secretion, which is essential for bacterial clearance from the lungs.

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.

Inhaled Tobramycin in Children with Acute Bacterial Rhinopharyngitis

Antibiotic abuse for treating rhinopharyngitis induces the occurrence of resistant bacteria. As topical drugs might reduce this phenomenon, the aims of our study were to evaluate inhaled tobramycin in children with acute bacterial rhinopharyngitis and to compare it with oral amoxicillin/clavulanate. The trial was conducted as randomized, parallel group and double blind. Children, aged 3–6 years, with acute bacterial rhinopharyngitis were treated with 15 mg of aerosolized tobramycin (Group A) or 50 mg/Kg of amoxicillin/clavulanate (Group B) twice daily for 10 days. The following parameters were assessed: nasal obstruction, mucopurulent rhinorrhea, post-nasal drip, adenoidal hypertrophy, tympanic inflammation, tympanogramm, rhinomanometry and cultures. Of 416 patients screened, 311 children (178 females and 133 males), median age 4.5 years, completed the study: 156 in Group A and 155 in Group B. Both treatments improved all parameters (p<0.01 for all). Intergroup analysis showed that inhaled tobramycin induced a better improvement versus amoxicillin/clavulanate concerning nasal obstruction (p<0.05), adenoidal hypertrophy (p<0.01), tympanic inflammation (p<0.01), rhinomanometry (p<0.01) and cultures (p<0.05). In conclusion, inhaled tobramycin may represent a valid treatment for acute bacterial rhinopharyngitis in children, as it is effective, safe, economic and simple to use.

Inhaled antibiotics for pulmonary exacerbations in cystic fibrosis

BACKGROUND

Cystic fibrosis is a genetic disorder in which abnormal mucus in the lungs is associated with susceptibility to persistent infection. Pulmonary exacerbations are when symptoms of infection become more severe. Antibiotics are an essential part of treatment for exacerbations and inhaled antibiotics may be used alone or in conjunction with oral antibiotics for milder exacerbations or with intravenous antibiotics for more severe infections. Inhaled antibiotics do not cause the same adverse effects as intravenous antibiotics and may prove an alternative in people with poor access to their veins. This is an update of a previously published review.

OBJECTIVES

To determine if treatment of pulmonary exacerbations with inhaled antibiotics in people with cystic fibrosis improves their quality of life, reduces time off school or work and improves their long-term survival.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Group's Cystic Fibrosis Trials Register. Date of the last search: 03 October 2018.We searched ClinicalTrials.gov, the Australia and New Zealand Clinical Trials Registry and WHO ICTRP for relevant trials. Date of last search: 09 October 2018.

SELECTION CRITERIA

Randomised controlled trials in people with cystic fibrosis with a pulmonary exacerbation in whom treatment with inhaled antibiotics was compared to placebo, standard treatment or another inhaled antibiotic for between one and four weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected eligible trials, assessed the risk of bias in each trial and extracted data. They assessed the quality of the evidence using the GRADE criteria. Authors of the included trials were contacted for more information.

MAIN RESULTS

Four trials with 167 participants are included in the review. Two trials (77 participants) compared inhaled antibiotics alone to intravenous antibiotics alone and two trials (90 participants) compared a combination of inhaled and intravenous antibiotics to intravenous antibiotics alone. Trials were heterogenous in design and two were only available in abstract form. Risk of bias was difficult to assess in most trials, but for all trials we judged there to be a high risk from lack of blinding and an unclear risk with regards to randomisation. Results were not fully reported and only limited data were available for analysis.Inhaled antibiotics alone versus intravenous antibiotics aloneOnly one trial (n = 18) reported a perceived improvement in lifestyle (quality of life) in both groups (very low-quality of evidence). Neither trial reported on time off work or school. Both trials measured lung function, but there was no difference reported between treatment groups (very low-quality evidence). With regards to our secondary outcomes, one trial (n = 18) reported no difference in the need for additional antibiotics and the second trial (n = 59) reported on the time to next exacerbation. In neither case was a difference between treatments identified (both very low-quality evidence). The single trial (n = 18) measuring adverse events and sputum microbiology did not observe any in either treatment group for either outcome (very low-quality evidence).Inhaled antibiotics plus intravenous antibiotics versus intravenous antibiotics aloneNeither trial reported on quality of life or time off work or school. Both trials measured lung function, but found no difference between groups in forced expiratory volume in one second (one trial, n = 28, very low-quality evidence) or vital capacity (one trial, n = 62). Neither trial reported on the need for additional antibiotics or the time to the next exacerbation; however, one trial (n = 28) reported on hospital admissions and found no difference between groups. Both trials reported no difference between groups in adverse events (very low-quality evidence) and one trial (n = 62) reported no difference in the emergence of antibiotic-resistant organisms (very low-quality evidence).

AUTHORS' CONCLUSIONS

There is little useful high-level evidence to judge the effectiveness of inhaled antibiotics for the treatment of pulmonary exacerbations in people with cystic fibrosis. The included trials were not sufficiently powered to achieve their goals. Hence, we are unable to demonstrate whether one treatment was superior to the other or not. Further research is needed to establish whether inhaled tobramycin may be used as an alternative to intravenous tobramycin for some pulmonary exacerbations.

Gallium disrupts bacterial iron metabolism and has therapeutic effects in mice and humans with lung infections

The lack of new antibiotics is among the most critical challenges facing medicine. The problem is particularly acute for Gram-negative bacteria. An unconventional antibiotic strategy is to target bacterial nutrition and metabolism. The metal gallium can disrupt bacterial iron metabolism because it substitutes for iron when taken up by bacteria. We investigated the antibiotic activity of gallium ex vivo, in a mouse model of airway infection, and in a phase 1 clinical trial in individuals with cystic fibrosis (CF) and chronic Pseudomonas aeruginosa airway infections. Our results show that micromolar concentrations of gallium inhibited P. aeruginosa growth in sputum samples from patients with CF. Ex vivo experiments indicated that gallium inhibited key iron-dependent bacterial enzymes and increased bacterial sensitivity to oxidants. Furthermore, gallium resistance developed slowly, its activity was synergistic with certain antibiotics, and gallium did not diminish the antibacterial activity of host macrophages. Systemic gallium treatment showed antibiotic activity in murine lung infections. In addition, systemic gallium treatment improved lung function in people with CF and chronic P. aeruginosa lung infection in a preliminary phase 1 clinical trial. These findings raise the possibility that human infections could be treated by targeting iron metabolism or other nutritional vulnerabilities of bacterial pathogens.

Pharmacokinetics and pharmacodynamics of high doses of inhaled dry powder drugs

For many years, administration of drugs by inhalation has been the mainstay treatment for obstructive respiratory disorders such as asthma and chronic obstructive pulmonary disease. Antibiotics and other drugs have been administered for decades as aerosols to treat other pulmonary disease in a clinical setting, but it was until the early 1980's that colistin was formally marketed as a solution for nebulization in Europe (Colomycin, Pharmax, Bexley). The solubility of other drugs and the size of the dose required to achieve therapeutic concentrations at the site of action, made treatment times long and difficult to be performed at home. High dose dry powder delivery is a potentially effective way to deliver low potency drugs such as antibiotics. There are three major barriers to achieving the desired pharmacodynamic effect with these compounds: aerosol delivery, lung deposition and clearance. The powder formulation and device technology influence aerosol generation and may influence the size of the dose that can be achieved by inhalation in one puff. The site of deposition in the lungs is dictated by mechanisms of deposition which are influenced by the aerosol properties, particularly aerodynamic particle size distribution and the anatomy and physiology of the lungs. Finally, mechanisms of clearance dictate the local and systemic disposition of the drug, which in turn affects its pharmacokinetics and ultimately the pharmacodynamic effect and efficacy of treatment. Each of these factors will be considered and the implications for antimicrobial agent delivery as a high dose delivery example will be given.

Daily spirometry in an acute exacerbation of adult cystic fibrosis patients

To help answer the question of length of intravenous antibiotics during an acute exacerbation of cystic fibrosis (CF), we had subjects to follow daily home spirometry while on intravenous antibiotics. CF patients, 18 and older, with an acute exacerbation requiring intravenous antibiotics had a daily FEV1. The average time to a 10% increase over their initial sick FEV1 was calculated, as well as the time to a new baseline. A total of 25 subjects completed the study. Ten of the 25 subjects did not have a sustainable 10% increase in FEV1. Of the 15 subjects with a sustainable 10% increase in FEV1, it took 5.2 days (±4.5) after day 1, while a new baseline was achieved on average at 6.6 days (±4.8) after day 1. Given the wide range of time to a 10% improvement and new baseline, it is recommended there should be flexibility in length of intravenous antibiotics in CF, not by a preset number.