Macrolides for Clinically Significant Bronchiectasis in Adults: Who Should Receive This Treatment?

New insights into iron uptake in Streptococcus mutans: evidence for a role of siderophore-like molecules

Streptococcus mutans, a gram-positive coccus commonly found in the human oral cavity, is the primary causative agent of dental caries as well as infective endocarditis. Bacteria produce potent iron chelators called siderophores to absorb iron. Because, there are few studies on siderophore-mediated iron transport in S. mutans, the current study investigates the presence of such a mechanism in S. mutans GS-5. Deferration of culture medium and different concentrations of 2, 2'-Bipyridyl has been used to simulate iron-restricted conditions. Iron restriction alters the colony morphology and slows bacterial growth. Cross-feeding conditioned medium into an iron-restricted medium promotes bacterial growth, indicating the presence of siderophore-like molecules. This was further confirmed by Chrome Azurol S (CAS) assay and Modified CAS-agar assay. Cśaky's and Arnow's assays detected the presence of hydroxamate and catecholate-type molecules in optimal and iron-restricted conditions, respectively. Further, the siderophore-like molecules were extracted and purified with thin layer chromatography (TLC). TLC elutes were also found to be positive for iron-chelation in CAS-agar assay and aided growth of S. mutans under iron-restricted conditions. LC-MS analysis of culture supernatants under iron-restricted conditions identified iron-binding small molecules, including a catechol structural motif. Computational analysis utilizing KEGG and BLASTp suggested homologues of siderophore biosynthesis and transport proteins, including genes associated with mutanobactin production. These findings indicate a possible siderophore-mediated iron uptake mechanism in S. mutans GS-5, warranting further molecular studies and advanced spectroscopic characterization of this unidentified siderophore. Once confirmed, this mechanism can be used as a potential drug target to control streptococcal infection.

Baseline characteristics of patients in the Chinese Bronchiectasis Registry (BE-China): a multicentre prospective cohort study

BACKGROUND

Bronchiectasis is a disease with a global impact, but most published data come from high-income countries. We aimed to describe the clinical characteristics of patients with bronchiectasis in China.

METHODS

The Chinese Bronchiectasis Registry (BE-China) is a prospective, observational cohort enrolling patients from 111 hospitals in China. Data on demographics, comorbidities, and aetiological testing results were collected from adult patients with bronchiectasis at baseline and annual follow-up. Patients who met the inclusion criteria (age ≥18 years; received chest high-resolution CT in the past year showing bronchiectasis affecting one or more lung lobes; and clinical history consistent with bronchiectasis, including chronic cough, daily sputum production, and history of exacerbations) were included. Patients with known cystic fibrosis were excluded. To investigate variations according to different economic regions, two groups were compared based on whether per capita disposable income of residents was greater than US$5553. Clinical characteristics were compared with the European (EMBARC) registry and other national registries.

FINDINGS

Between Jan 10, 2020, and March 31, 2024, 10 324 patients from 97 centres were included in the study. Among 9501 participants with available data, the most common cause of bronchiectasis was post-infective disease (4101 [43·2%] patients), followed by idiopathic (2809 [29·6%] patients). 6676 (70·0%) of 9541 patients with available data had at least one exacerbation in the year before enrolment and 5427 (57·2%) of 9489 patients with available data were hospitalised at least once due to exacerbations. Treatments commonly used in high-income countries, such as inhaled antibiotics and macrolides, were infrequently used in China. Implementation of airway clearance in China was scarce, with only 1177 (12·2%) of 9647 patients having used at least one method of airway clearance. Compared with upper-middle-income regions, patients from lower-middle-income regions were younger (61·0 years [SD 14·0] vs 63·9 years [14·2]) with a higher proportion of pulmonary comorbidities (521 [17·8%] of 2922 patients vs 639 [8·6%] of 7402 with chronic obstructive pulmonary disease and 194 [6·6%] of 2922 patients vs 364 [4·9%] of 7402 patients with asthma), a higher tuberculosis burden (442 [16·0%] of 2768 patients vs 715 [10·6%] of 6733 patients), more severe radiological involvement (1160 [42·4%] of 2736 patients vs 2415 [35·4%] of 6816 patients with cystic bronchiectasis), more exacerbations (median 1·4 [IQR 0-2] in both groups; mean 1·4 [SD 1·6] vs 1·2 [1·4] in the previous year) and hospitalisations (1662 [60·6%] of 2743 patients vs 3765 [55·8%] of 6746 patients hospitalised at least once in the previous year), and poorer quality of life (median 57·4 [IQR 53·5-63·1] vs 58·7 [54·8-64·8] assessed by the Bronchiectasis Health Questionnaire).

INTERPRETATION

The clinical characteristics of patients with bronchiectasis in China show differences compared with cohorts in Europe and India. Bronchiectasis is more severe with a higher burden of exacerbations in lower-income regions. The management of patients with bronchiectasis in China urgently needs standardisation and improvement.

FUNDING

National Natural Science Foundation of China, Innovation Program of the Shanghai Municipal Education Commission, Program of the Shanghai Municipal Science and Technology Commission, and Program of the Shanghai Shenkang Development Center.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Investigation and Management of Bronchiectasis in Nontuberculous Mycobacterial Pulmonary Disease

Patients with nontuberculous mycobacterial (NTM) lung infection require life-long attention to their bronchiectasis, whether or not their NTM infection has been cured. The identification of the cause of bronchiectasis and/or coexisting diseases is important because it may affect therapeutic strategies. Airway clearance is the mainstay of bronchiectasis management. It can include multiple breathing techniques, devices, and mucoactive agents. The exact airway clearance regimen should be customized to each individual patient. Chronic pathogenic airway bacteria, such as Pseudomonas aeruginosa, may warrant consideration of eradication therapy and/or chronic use of maintenance inhaled antibiotics.

Daily versus three-times-weekly azithromycin in Chinese patients with non-cystic fibrosis bronchiectasis: protocol for a prospective, open-label and randomised controlled trial

INTRODUCTION

Non-cystic fibrosis bronchiectasis (NCFB) brought a heavy healthcare burden worldwide. Macrolide maintenance therapy was proved to be helpful in reducing exacerbation of NCFB. However, the optimal dosing regimens of macrolides have not been determined, and its efficacy in Chinese NCFB population has not been validated. This protocol describes a head-to-head clinical trial designed to compare the efficacy of two dosing regimens of azithromycin in Chinese NCFB population.

METHODS AND ANALYSIS

This prospective, open-label and randomised controlled trial will be conducted in the First People's Hospital of Jiashan, China. Eligible patients with high-resolution CT defined NCFB will be randomly divided into three groups, which will receive either 250 mg daily azithromycin, or 500 mg three-times-weekly azithromycin or no treatment for 6 months. They will be followed up for another 6 months without treatment. The primary outcome is the mean rate of protocol-defined pulmonary exacerbation at 6 months.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the First People's Hospital of Jiashan Ethics Committee. The findings will be disseminated in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ChiCTR2100052906.

Expert recommendations on the role of macrolides in chronic respiratory diseases

Background:

India contributes to 32% of the total global disability-adjusted life years, due to chronic respiratory diseases. This has led to a high rate of health loss from these diseases. Antibiotics are commonly used in the management of respiratory disorders. With excellent tissue penetration, prolonged tissue persistence, and favorable side effect profile, macrolides are one of the best treatment options being recommended for respiratory, urogenital, dermal, and other bacterial infections. Still, there is a lack of clinical trial data on the use of macrolides in the management of respiratory chronic disease, and hence, there is a need for clinical guidance on their use in Indian setting.

Methods:

A systematic review of the literature was conducted on PubMed, Cochrane database, and Google Scholar. Existing guidelines, meta-analyses, systematic reviews, randomized controlled trials (RCTs), non-RCTs, landmark studies, and key-cited articles were selected. Recommendations were based on available evidence and expert panel's logical empiricism and consensus.

Results and Discussion:

This article discusses evidence-based and clinical practice based management of chronic respiratory conditions including chronic obstructive pulmonary disease, asthma, bronchiectasis, diffusive panbronchiolitis, and organizing pneumonia. The authors reviewed different respiratory conditions, role of macrolides in their management, adverse events and antimicrobial resistance associated with macrolides, evidence review of various clinical trials, guideline recommendations, and clinical recommendations.

Azithromycin Prescribing by Respiratory Pediatricians in Australia and New Zealand for Chronic Wet Cough: A Questionnaire-Based Survey

Aims: To determine how respiratory pediatricians across Australia and New Zealand prescribe azithromycin for children with chronic wet cough, including recurrent protracted bacterial bronchitis, chronic suppurative lung disease (CSLD) and bronchiectasis. Methods: A prospective web-based questionnaire was emailed to members of the Pediatric Special Interest Group of the Thoracic Society of Australia and New Zealand (TSANZ) between April and May 2018. It comprised eight demographic and 15 clinically focused questions. Results: Of the 73 respiratory pediatricians listed across Australia and New Zealand, 29 (40%) responded and all prescribed azithromycin for chronic wet cough. Twelve (41%) indicated that they would consider prescribing a short-course (2-4 weeks) of azithromycin for children with a chronic wet cough. Although most respondents reported prescribing long-term (>4-weeks) azithromycin for either CSLD (n = 23, 79%) or bronchiectasis (n = 24, 83%), only nine (31%) respondents would commence treatment if in the previous 12-months these children experienced three non-hospitalized exacerbations and just 12 (41%) would do so if there had been two hospitalisations for severe exacerbations during the same period in accordance with the TSANZ national guidelines. A lower threshold for prescribing azithromycin was described for Indigenous children or if co-morbidities were present. None prescribed azithromycin for >24-months. Macrolide-resistance was reported in Streptococcus pneumoniae and Staphylococcus aureus. Conclusion: Although Australian and New Zealand respiratory pediatricians in this survey prescribed azithromycin for chronic wet cough most often in children with either CSLD or bronchiectasis, many did so outside the current national guidelines. Reasons for this need exploring.

Application of Antibiotics/Antimicrobial Agents on Dental Caries

Dental caries is the most common oral disease. The bacteriological aetiology of dental caries promotes the use of antibiotics or antimicrobial agents to prevent this type of oral infectious disease. Antibiotics have been developed for more than 80 years since Fleming discovered penicillin in 1928, and systemic antibiotics have been used to treat dental caries for a long time. However, new types of antimicrobial agents have been developed to fight against dental caries. The purpose of this review is to focus on the application of systemic antibiotics and other antimicrobial agents with respect to their clinical use to date, including the history of their development, and their side effects, uses, structure types, and molecular mechanisms to promote a better understanding of the importance of microbial interactions in dental plaque and combinational treatments.

Bronchiectasis update

PURPOSE OF REVIEW

Bronchiectasis, once thought to be an orphan disease, is being diagnosed with increased frequency in the United States and around the world. The present review aims to provide an update on recent publications on the diagnosis and management of bronchiectasis.

RECENT FINDINGS

Two large bronchiectasis patient registries have published initial reports regarding demographics and other patient data in 2017. Updates on the microbiology, microbiome, and inflammation in patients with bronchiectasis are clarifying the complexities of airway infection in this disease. A consensus definition of 'exacerbation' in bronchiectasis has been agreed upon this year. Reports on novel treatments, including the repurposing of older therapies, have also been published in 2016-2017. A new European guideline for the management of adult bronchiectasis is also now available.

SUMMARY

Bronchiectasis, a resurgent disease, is now being better defined with a rapidly expanding portfolio of demographic, clinical, and therapeutic research and publications.

A review of non-cystic fibrosis bronchiectasis in children with a focus on the role of long-term treatment with macrolides

Bronchiectasis is a rare chronic airway disease arising from several respiratory and systemic diseases. The grade of evidence for specific treatment of childhood bronchiectasis unrelated to cystic fibrosis (CF) is low with very few randomized controlled trials. Treatment has been based mainly on evidence from studies in adults with non-cystic fibrosis bronchiectasis and patients with cystic fibrosis. Recently, long-term treatment with macrolides has been proposed. These molecules offer the advantage of anti-inflammatory and immunomodulatory properties in addition to their antibacterial properties. A total of three randomized double-blind placebo-controlled trials conducted in adults showed that macrolides taken for 6-12 months led to a significant reduction in exacerbation rates. Only one long-term, randomized double-blind placebo-controlled trial was conducted in the pediatric population. It showed that azithromycin administered weekly for up to 24 months reduced pulmonary exacerbations. Further randomized controlled studies are needed to determine the optimal dose and duration of treatment with macrolides. The clinical profile of children who would benefit from this treatment also needs to be determined.

Azithromycin or erythromycin? Macrolides for non-cystic fibrosis bronchiectasis in adults: A systematic review and adjusted indirect treatment comparison

Non-cystic fibrosis (non-CF) bronchiectasis is a condition characterized by an airway inflammatory response to bacterial pathogens. Frequent exacerbations have a major influence on the quality of life. Macrolide antibiotics have not only antibacterial but also immune-regulation effects. It is proved that macrolides have a benefit in preventing exacerbations. However, it is still uncertain whether azithromycin or erythromycin is more effective and safe. The purpose of this study was to answer the following question: Which kind of macrolide antibiotic is more effective and safe in preventing non-CF bronchiectasis exacerbation? We conducted a systematic review to identify randomized clinical trials published up to May 2017 that reported on macrolides for non-CF bronchiectasis and an adjusted indirect treatment comparison (AITC) between macrolides to evaluate their efficacy and safety. The direct comparison meta-analysis found that macrolides decreased the rate of exacerbation of non-CF bronchiectasis (risk ratio (RR) = 0.45; 95% confidence interval (CI) 0.36-0.55) with heterogeneity ( I2 = 63.7%, p = 0.064). The AITC showed that azithromycin had a significantly lower bronchiectasis exacerbation rate than erythromycin (RR = 0.35; 95% CI: 0.403-0.947). Azithromycin increased the risk of diarrhea and abnormal pain. This meta-analysis suggested that long-term treatment with macrolides significantly reduced the incidence of non-CF bronchiectasis exacerbation. Moreover, azithromycin is more efficient than roxithromycin and erythromycin in preventing exacerbation.

Bronchiectasis: Treatment decisions for pulmonary exacerbations and their prevention

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

Non-cystic fibrosis bronchiectasis in the elderly: current perspectives

Bronchiectasis is a chronic lung disease with permanently damaged airways predisposing to recurrent respiratory tract infections. There is an increasing prevalence of bronchiectasis in the elderly, affecting approximately 10 patients per 1,000 population. Studies have shown that older, frailer patients tend to have a more severe and symptomatic disease, with those aged 80 and above with worse quality of life, increased hospitalization and increased mortality. These patients will be encountered by clinicians working in all aspects of elderly care. This review covers the various investigations and aspects of treatment for bronchiectasis and how they may be utilized in a more older and generally frailer population.

Phosphoinositide 3-kinase δ (PI3Kδ) in respiratory disease

Defining features of chronic airway diseases include abnormal and persistent inflammatory processes, impaired airway epithelial integrity and function, and increased susceptibility to recurrent respiratory infections. Phosphoinositide 3-kinases (PI3K) are lipid kinases, which contribute to multiple physiological and pathological processes within the airway, with abnormal PI3K signalling contributing to the pathogenesis of several respiratory diseases. Consequently, the potential benefit of targeting PI3K isoforms has received considerable attention, being viewed as a viable therapeutic option in inflammatory and infectious lung disorders. The class I PI3K isoform, PI3Kδ (Phosphoinositide 3-kinases δ) is of particular interest given its multiple roles in modulating innate and adaptive immune cell functions, airway inflammation and corticosteroid sensitivity. In this mini-review, we explore the role of PI3Kδ in airway inflammation and infection, focusing on oxidative stress, ER stress, histone deacetylase 2 and neutrophil function. We also describe the importance of PI3Kδ in adaptive immune cell function, as highlighted by the recently described Activated PI3K Delta Syndrome, and draw attention to some of the potential clinical applications and benefits of targeting this molecule.

The Role of Other Bacteria, Fungi, and Viruses in Bronchiectasis

Bronchiectasis, a heterogeneous disease, is characterized by a vicious cycle of airway infection and inflammation that results in structural damage to the airways and the surrounding lung parenchyma [1]. Many microorganisms have been associated with bronchiectasis, both as a complication of the anatomic abnormalities and possibly as a cause of the structural disease as well [2, 3]. Diverse polymicrobial communities are present in the airways of patients with bronchiectasis [4]. Studies using standard microbiologic culture techniques have demonstrated the presence of bacterial, fungal, and viral pathogens in the lungs of bronchiectasis patients both when the patient is clinically stable and when there is an exacerbation of disease [2, 5]. Newer molecular techniques have broadened our understanding of the microbiome in bronchiectasis patients [4, 6]. Pseudomonas aeruginosa has been repeatedly shown to be a problematic pathogen in patients with bronchiectasis and is associated with a worse prognosis [7, 8]. Multiple epidemiologic reports have shown that approximately 20–35% of patients worldwide with bronchiectasis are chronically infected with P. aeruginosa [2, 9, 10]. Several antibiotic trials have been published where the main target of therapy is Pseudomonas aeruginosa [11–17]. (See Chap. 10.1007/978-3-319-61452-6_11 for a full review of P. aeruginosa infections associated with bronchiectasis.) Another problematic group of pathogens, nontuberculous mycobacteria (NTM), is a common infecting organism in bronchiectasis, particularly in the United States and in parts of Asia [2, 18]. NTM infection is fully discussed in Chap. 10.1007/978-3-319-61452-6_13. In this chapter, we will review the role of bacterial pathogens other than P. aeruginosa and the impact of fungal and viral infections in bronchiectasis patients. (See Table 13.1.)

An update on the pharmacotherapeutic management of lower respiratory tract infections

INTRODUCTION

Our knowledge about lower respiratory tract infections (LRTIs) has improved substantially in the last years, but the management of respiratory infections is still a challenge and we are still far from using precision medicine in their treatment. Areas covered: The approaches developed in recent years to improve the pharmacotherapeutic management of LRTIs, such as novel diagnostic assays to facilitate medical decision-making, attempts for selecting an optimal empiric antibiotic regimen, and the role of new and possibly unproven adjunctive therapies, are described. Expert opinion: Early and appropriate antibiotics remain the cornerstone in the treatment of LRTIs. The updated trend is to apply antimicrobial stewardship principles and initiatives to optimize both the management and the outcomes of LTRIs. Biomarkers, mainly C-reactive protein (CRP) and procalcitonin (PCT), can improve the diagnostic and prognostic assessment of LRTIs and aid to guide antibiotic therapy. The widespread use of antimicrobial agents has greatly contributed to faster development of antibiotic resistance and the emergence of opportunistic pathogens, which substitute the indigenous microbiota. However, very few new antibiotics in development to overcome existing resistance and ensure continued success in the treatment of LRTIs have been approved, likely because antibiotic stewardship programs discourage the use of new agents.

Bronchiectasis in the Last Five Years: New Developments

Bronchiectasis, a chronic lung disease characterised by cough and purulent sputum, recurrent infections, and airway damage, is associated with considerable morbidity and mortality. To date, treatment options have been limited to physiotherapy to clear sputum and antibiotics to treat acute infections. Over the last decade, there has been significant progress in understanding the epidemiology, pathophysiology, and microbiology of this disorder. Over the last five years, methods of assessing severity have been developed, the role of macrolide antibiotic therapy in reducing exacerbations cemented, and inhaled antibiotic therapies show promise in the treatment of chronic Pseudomonas aeruginosa infection. Novel therapies are currently undergoing Phase 1 and 2 trials. This review aims to address the major developments within the field of bronchiectasis over this time.