Protracted Bacterial Bronchitis in Children: Natural History and Risk Factors for Bronchiectasis

Exploiting haem-iron dependence of nontypeable Haemophilus influenzae: an avenue for future therapeutic development

Nontypeable Haemophilus influenzae (NTHi) is a major respiratory pathogen that imposes a substantial disease burden, globally. Further amplifying the burden of NTHi-associated infections is the rapidly expanding spectrum and prevalence of antibiotic resistance, and the lack of an effective vaccination strategy. In 2017, the World Health Organization list of "priority pathogens", highlighted the urgent need for new therapeutic agents against NTHi. Consequently, alternative preventative or treatment approaches that do not rely on antibiotic susceptibility or stable vaccine targets are becoming more attractive. The nutritional dependency for haem/iron at all stages of NTHi pathogenesis exposes a vulnerability that may be exploited for the development of such therapies. This review explores the role of haem/iron in all facets of NTHi pathogenesis, the host-bacterial competition for this vital nutrient, and the therapeutic potential of strategies that interfere with its acquisition.

Long-Term Pulmonary Sequelae 5-14 Years After Protracted Bacterial Bronchitis in Early Childhood

BACKGROUND

There is little information about long-term changes in pulmonary function tests (PFTs) many years after protracted bacterial bronchitis (PBB), the most common cause of chronic wet cough in early childhood.

METHODS

Of 200 consecutively recruited children with a previously proven diagnosis of PBB 62 (12.2 years, female 48%) were interviewed after 7.7 (5.4-14.7) years about their previous and current symptoms and pulmonary function tests (PFTs: spirometry, body plethysmography, nitrogen multi-breath washout, exhaled nitric oxide and nasal nitric oxide) were performed. Children with persistent symptoms were offered lung imaging.

RESULTS

11 (17.7%) patients suffered from chronic or recurring wet cough years after their first PBB episode. 15 (24.19%) had at least one abnormal spirometry parameter. FEV1 was abnormal in eight of 62 (12.9%), LCI 2.5% in seven of 56 (12.5%), FVC in 12 of 62 (19.35%) and FEV1/FVC in five of 62 (8.06%) cases. PFT did not differ between children with and without wet cough. Lung MRI/CT demonstrate in four of nine cases abnormalities of the bronchial walls, including one with incipient bronchiectasis.

CONCLUSION

After PBB in early childhood, a significant proportion of children suffer from respiratory symptoms many years later, some have an objectively reduced lung function and structural changes of the bronchial wall despite adequate initial therapy. Wet cough alone seems not to be a sensitive clinical predictor. Due to the retrospective study design, we cannot proof any causal relationship. However, to detect late bronchopulmonary sequelae, continuous follow-up of these children should become mandatory.

Mucolytics for children with chronic suppurative lung disease

BACKGROUND

Chronic suppurative lung disease (CSLD) is an umbrella term to define the spectrum of endobronchial suppurative lung disease, including bronchiectasis and protracted bacterial bronchitis (PBB), associated with chronic wet or productive cough. Research that explores new therapeutic options in children with CSLD has been identified by clinicians and patients as one of the top research priorities. Mucolytic agents work to improve mucociliary clearance and interrupt the vicious vortex of airway infection and inflammation, hence they have potential as a therapeutic option.

OBJECTIVES

To assess the effects of mucolytics for reducing exacerbations, improving quality of life and other clinical outcomes in children with CSLD (including PBB and bronchiectasis), and to assess the risk of harm due to adverse events.

SEARCH METHODS

An Information Specialist searched the Cochrane Airways Trials Register to June 2022, and a review author searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase databases to 27 September 2024. Other review authors handsearched respiratory journals.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), of both cross-over and parallel design, that compared a mucolytic with a placebo or 'no intervention' control group and included children (aged 18 years and under) with any type of CSLD (including PBB and bronchiectasis). We excluded studies with adult participants and studies in children with cystic fibrosis, empyema, pulmonary abscess or bronchopulmonary fistula.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed titles and abstracts to assess eligibility for inclusion. The authors then assessed study quality and extracted data. They assessed the quality of the study using the Cochrane risk of bias tool (RoB 2), and used GRADE to assess the certainty of evidence. Outcomes of interest to be analysed included: i) for maintenance or stable state: rate of exacerbations, ii) for exacerbation state: time to resolution of respiratory exacerbation, iii) lung function - forced expiratory volume in one second (FEV1) and forced vital capacity (FVC), iv) quality of life and v) adverse events. Only one study met the inclusion criteria, so we could not perform a meta-analysis. Data were continuous, so we reported outcomes as mean differences.

MAIN RESULTS

The sole included RCT was a cross-over study of 63 children in the total cohort, with reported data and analysis of only 52 children (26 per arm) with non-cystic fibrosis bronchiectasis. The study compared 3% hypertonic saline nebulised before chest physiotherapy with a control arm (physiotherapy alone), with each phase lasting eight weeks. Children in the hypertonic saline arm had a mean age of 9.80 (SD 2.97) years and 42.3% were male; those in the control arm had a mean age of 9.10 (SD 2.40) years and 38.4% were male. Only results of the first arm of the cross-over study were included in this review. The RCT reported a clinically important difference between the groups for our review's primary outcome: rate of respiratory exacerbations. The mean number of exacerbations per child-year was 2.50 (SD 0.64) in the intervention group and 7.80 (SD 1.05) in the control group (mean difference (MD) -5.30, 95% CI -5.77 to -4.83; 1 study, 52 participants; very low-certainty evidence). The RCT also reported that the percentage point improvement in mean % predicted FEV1 and FVC from baseline to week eight was better with hypertonic saline compared to control. Mean FEV1 improvement was 14.15% (SD 5.50) in the intervention group versus 5.04% (SD 5.55) in the control group (MD 9.11%, 95% CI 6.11 to 12.11; 1 study, 52 participants; very low-certainty evidence). While for FVC, the mean improvement was 13.77% (SD 5.73) compared with 7.54% (SD 4.90), respectively (MD 6.23%, 95% CI 3.33 to 9.13; 1 study, 52 participants; very low-certainty evidence). Quality of life measures were not used. We judged the study to have a high risk of bias due to unblinding, missing data, deviation from the intended intervention and reporting bias with measurement and selection of outcome measures. The authors reported that there were no dropouts due to adverse events. No data were available regarding quality of life. The included study assessed mucolytic use during a stable state, and we found no studies of mucolytic use during an exacerbation. We also found no studies assessing oral mucolytics, other inhaled mucolytics, use in PBB, or in settings other than hospital outpatients. We also found two ongoing studies, one using hypertonic saline and one using an oral mucolytic agent erdosteine, which will potentially be included in future updates of this review.

AUTHORS' CONCLUSIONS

This systematic review is limited to a single small study, which we judged to be at high risk of bias. It remains uncertain whether regular nebulised hypertonic saline during a stable state reduces exacerbations or improves lung function. Further multi-centre, well-designed RCTs of longer duration that investigate various mucolytics are required to answer this important clinical question.

Assessing the feasibility of breath collection from conscious young children to support volatilome analysis: insights into age limitations and breath sampling requirements

Breath volatile organic compounds (VOCs) are increasingly under consideration as biomarkers of respiratory disease. Although numerous studies have identified VOCs that distinguish patient groups, a lack of standardisation among published studies has impeded translation into clinical diagnostics. Standardised breath collection protocols have been proposed for adults and children aged >4 years, but optimal methods for collecting breath from younger children remain to be determined. The aim of this study was to assess the feasibility and acceptability of breath sampling among a young paediatric cohort. A total of 61 children (age 6 months-12 years) were recruited prospectively to observational studies of chronic cough at two study sites. Mixed expiratory breath was collected into 1 l Tedlar Bags using either a drinking straw, mouthpiece, or mask. After concentrating onto thermal desorption tubes, the breath was analysed using two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. Breath collection via a mouthpiece was highly feasible for children aged >2 years. Mask-based collection was required for younger children but was poorly tolerated. Drinking straw-based collections were unsuitable for some children aged <4 years due to challenges maintaining a sufficient seal. At least 700 ml of breath was sampled from 72.6% of children. The number of peaks per sample, total peak area per sample, and composition of breath VOCs were all consistent with successful breath sampling. The high feasibility of breath collection via a mouthpiece in our study suggests established protocols designed for children aged over 4 years can be used with confidence for children from as young as 2 years of age.

Welcome to Asthma Neverland

Asthma is a multifactorial disease with heterogeneous clinical and pathophysiological phenotypes. Classical symptoms of asthma are wheeze, cough and breathlessness, and occasionally chest tightness. These symptoms are common to many respiratory and non-respiratory conditions, and misdiagnosis of asthma is frequent. There is no definitive test for the diagnosis of asthma, but a combination of a suggestive medical history, physical examination, lung function tests, and additional investigations will maximize the chances of making a correct diagnosis. Despite clear statements in international asthma guidelines, there are many gaps when performing diagnostic steps in current medical practice. An incomplete medical history, poor attention to the nature of respiratory sounds, failure to carry out objective tests, and inadequate estimation of the response to anti-asthma therapy are the main factors responsible for misdiagnosis of asthma. The use of wrong and potentially dangerous therapies, and high consumption of healthcare resources are the inevitable consequences of misdiagnosis. The main alternative diagnoses to asthma, clinical clues and objective tests useful for specific diagnoses are critically discussed.

Lung function trajectories in children with early diagnosis of non-cystic fibrosis bronchiectasis: a retrospective observational study

BACKGROUND

Non-cystic fibrosis (non-CF) bronchiectasis (BE) is defined as a clinical syndrome of recurrent, persistent wet cough and abnormal bronchial dilatation on chest High Resolution Computed Tomography (HRCT) scans. The aims of this study were to characterize the pattern of the trajectories of lung function parameters and to consider the relationship between the lung function and radiological severity according to the modified Reiff score.

METHODS

The study retrospectively considered 86 children (46.5% male, median age of 4 years) with non-CF BE, admitted at the Paediatric Pneumology Unit of Buzzi Children's Hospital from January 2015 to December 2022. The diagnosis of BE was made according to the presence of a suggestive clinical history and symptoms and key features of BE evidenced on chest HRCT scans. The modified Reiff score was adapted to quantify the severity of BE. Spirometry (COSMED MicroQuark spirometer) was performed at median age of 5.78 years (baseline or T0) and after 1 and 2 years from the baseline (T1 and T2, respectively). The general trends of lung function parameters were estimated by ANOVA models for repeated measurements. For each lung function parameter, a longitudinal regression model was fitted. The analysis was performed with the software R release 4.2.3. The statistical significance was deemed when the p-value resulted lower than 0.05.

RESULTS

The general trends of lung function parameters showed a statistically significant variation of forced vital capacity (FVC%) and forced expiratory volume in 1s (FEV1%) from T0 to T1 (p = 0.0062, 0.0009) and no significant change for FVC%, FEV1% and forced expiratory flow 25-75% of VC (FEF25/75%) from T1 to T2 (p = 0.145, 0.210, 0.600, respectively). Notably, we found no correlation between the age at diagnosis and the lung function parameters at T0 (r = 0.149, 0.103 and 0.042 for FVC%, FEV1% and FEF25/75%, respectively). Instead, a poor negative correlation resulted between the Reiff score and FVC%, FEV1% e FEF25/75% at baseline (Spearman coefficients: rho=-0.156, -0.204, -0.103, respectively).

CONCLUSIONS

A stable pulmonary function is detectable within 2 years follow up from baseline spirometry. The modified Reiff score should be considered as a good tool not only to quantify the radiological lung involvement but also the degree of pulmonary function impairment.

Role of Spirometry, Radiology, and Flexible Bronchoscopy in Assessing Chronic Cough in Children

Chronic cough in children is a common and multifaceted symptom, often requiring a comprehensive approach for accurate diagnosis and effective management. This review explores the use of spirometry, radiology (chest X-rays and computed tomography (CT) scans), and flexible bronchoscopy in the assessment of chronic cough in children through current guidelines and studies. The strengths, clinical indications, and limitations of each modality are examined. Spirometry, radiology, and in some cases flexible bronchoscopy are integral to the assessment of chronic cough in children; however, a tailored approach, leveraging the strengths of each modality and guided by clinical indications, enhances diagnostic accuracy and therapeutic outcomes of pediatric chronic cough.

Postinfectious Pulmonary Complications: Establishing Research Priorities to Advance the Field: An Official American Thoracic Society Workshop Report

Continued improvements in the treatment of pulmonary infections have paradoxically resulted in a growing challenge of individuals with postinfectious pulmonary complications (PIPCs). PIPCs have been long recognized after tuberculosis, but recent experiences such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic have underscored the importance of PIPCs following other lower respiratory tract infections. Independent of the causative pathogen, most available studies of pulmonary infections focus on short-term outcomes rather than long-term morbidity among survivors. In this document, we establish a conceptual scope for PIPCs with discussion of globally significant pulmonary pathogens and an examination of how these pathogens can damage different components of the lung, resulting in a spectrum of PIPCs. We also review potential mechanisms for the transition from acute infection to PIPC, including the interplay between pathogen-mediated injury and aberrant host responses, which together result in PIPCs. Finally, we identify cross-cutting research priorities for the field to facilitate future studies to establish the incidence of PIPCs, define common mechanisms, identify therapeutic strategies, and ultimately reduce the burden of morbidity in survivors of pulmonary infections.

Rasch validation of the short form (8 item) PC-QoL questionnaire and applicability of use as a health state classification system for a new preference-based measure

BACKGROUND

The parent-proxy paediatric chronic cough quality of life questionnaire (PC-QoL) is a commonly used measure of spillover quality of life in parents of children with chronic cough. To date, spillover health utility in these parents is not routinely estimated largely due to the lack of a suitable instrument. Their perspective is not included in economic evaluations of interventions for their children. We explored developing a health state classification system based on the PC-QoL for measuring health utility spill over in this population.

METHODS

This study included PC-QoL 8-item responses of 653 parents participating in a prospective cohort study about paediatric chronic cough. Exploratory factor analysis (EFA) and Rasch analysis were used to examine dimensionality and select potential items and level structure.

RESULTS

EFA indicated that the PC-QoL had one underlying domain. Rasch analysis indicated threshold disordering in all items which improved when items were collapsed from seven to four levels. Two demonstrated differential item functioning (DIF) by diagnosis or ethnicity and were excluded from the final scale. This scale satisfied Rasch assumptions of local independence and unidimensionality and demonstrated acceptable fit to the Rasch model. It was presented to and modified by an expert panel and a consumer panel. The resulting classification system had six items, each with four levels.

DISCUSSION

The PC-QoL can conform to a Rasch model with minor modifications. It may be a good basis for the classification system of a child cough-specific PBM. A valuation study is required to estimate preference weights for each item and to estimate health utility in parents of children with chronic cough.

Cough in Protracted Bacterial Bronchitis and Bronchiectasis

Chronic cough in children is a common condition for which patients seek medical attention, and there are many etiologies. Of the various causes of chronic cough in children, protracted bacterial bronchitis (PBB) is one of the commonest causes, and bronchiectasis is one of the most serious. Together, they lie on different ends of the spectrum of chronic wet cough in children. Cough is often the only symptom present in children with PBB and bronchiectasis. This review highlights the role of cough as a marker for the presence of these conditions, as well as an outcome endpoint for treatment and research.

Lung microbiome: new insights into bronchiectasis' outcome

The present treatments for bronchiectasis, which is defined by pathological dilatation of the airways, are confined to symptom relief and minimizing exacerbations. The condition is becoming more common worldwide. Since the disease's pathophysiology is not entirely well understood, developing novel treatments is critically important. The interplay of chronic infection, inflammation, and compromised mucociliary clearance, which results in structural alterations and the emergence of new infection, is most likely responsible for the progression of bronchiectasis. Other than treating bronchiectasis caused by cystic fibrosis, there are no approved treatments. Understanding the involvement of the microbiome in this disease is crucial, the microbiome is defined as the collective genetic material of all bacteria in an environment. In clinical practice, bacteria in the lungs have been studied using cultures; however, in recent years, researchers use next-generation sequencing methods, such as 16S rRNA sequencing. Although the microbiome in bronchiectasis has not been entirely investigated, what is known about it suggests that Haemophilus, Pseudomonas and Streptococcus dominate the lung bacterial ecosystems, they present significant intraindividual stability and interindividual heterogeneity. Pseudomonas and Haemophilus-dominated microbiomes have been linked to more severe diseases and frequent exacerbations, however additional research is required to fully comprehend the role of microbiome in the evolution of bronchiectasis. This review discusses recent findings on the lung microbiota and its association with bronchiectasis.

Chronic Bronchitis in Children and Adults: Definitions, Pathophysiology, Prevalence, Risk Factors, and Consequences

The complex nature of chronic bronchitis (CB) and changing definitions have contributed to challenges in understanding its aetiology and burden. In children, CB is characterised by persistent airway inflammation often linked to bacterial infections and is therefore termed "protracted bacterial bronchitis" (PBB). Longitudinal studies suggest that CB in childhood persists into adulthood in a subgroup. It can also be associated with future chronic respiratory diseases including asthma, bronchiectasis, and chronic obstructive pulmonary disease (COPD). Adult CB is traditionally associated with smoking, occupational exposures, and lower socioeconomic status. The interplay between risk factors, childhood CB, adult CB, and other chronic respiratory diseases is intricate, requiring comprehensive longitudinal studies for a clearer understanding of the natural history of CB across the lifespan. Such longitudinal studies have been scarce to date given the logistic challenges of maintaining them over time. In this review, we summarise current evidence on the evolution of the definitions, pathophysiology, risk factors, and consequences of childhood and adulthood chronic bronchitis.

Heme sequestration by hemophilin from Haemophilus haemolyticus reduces respiratory tract colonization and infection with non-typeable Haemophilus influenzae

Iron acquisition is a key feature dictating the success of pathogen colonization and infection. Pathogens scavenging iron from the host must contend with other members of the microbiome similarly competing for the limited pool of bioavailable iron, often in the form of heme. In this study, we identify a beneficial role for the heme-binding protein hemophilin (Hpl) produced by the non-pathogenic bacterium Haemophilus haemolyticus against its close relative, the opportunistic respiratory tract pathogen non-typeable Haemophilus influenzae (NTHi). Using a mouse model, we found that pre-exposure to H. haemolyticus significantly reduced NTHi colonization of the upper airway and impaired NTHi infection of the lungs in an Hpl-dependent manner. Further, treatment with recombinant Hpl was sufficient to decrease airway burdens of NTHi without exacerbating lung immunopathology or systemic inflammation. Instead, mucosal production of the neutrophil chemokine CXCL2, lung myeloperoxidase, and serum pro-inflammatory cytokines IL-6 and TNFα were lower in Hpl-treated mice. Mechanistically, H. haemolyticus suppressed NTHi growth and adherence to human respiratory tract epithelial cells through the expression of Hpl, and recombinant Hpl could recapitulate these effects. Together, these findings indicate that heme sequestration by non-pathogenic, Hpl-producing H. haemolyticus is protective against NTHi colonization and infection.

IMPORTANCE

The microbiome provides a critical layer of protection against infection with bacterial pathogens. This protection is accomplished through a variety of mechanisms, including interference with pathogen growth and adherence to host cells. In terms of immune defense, another way to prevent pathogens from establishing infections is by limiting the availability of nutrients, referred to as nutritional immunity. Restricting pathogen access to iron is a central component of this approach. Here, we uncovered an example where these two strategies intersect to impede infection with the respiratory tract bacterial pathogen Haemophilus influenzae. Specifically, we find that a non-pathogenic (commensal) bacterium closely related to H. influenzae called Haemophilus haemolyticus improves protection against H. influenzae by limiting the ability of this pathogen to access iron. These findings suggest that beneficial members of the microbiome improve protection against pathogen infection by effectively contributing to host nutritional immunity.

Lung microbiome: new insights into the pathogenesis of respiratory diseases

The lungs were long thought to be sterile until technical advances uncovered the presence of the lung microbial community. The microbiome of healthy lungs is mainly derived from the upper respiratory tract (URT) microbiome but also has its own characteristic flora. The selection mechanisms in the lung, including clearance by coughing, pulmonary macrophages, the oscillation of respiratory cilia, and bacterial inhibition by alveolar surfactant, keep the microbiome transient and mobile, which is different from the microbiome in other organs. The pulmonary bacteriome has been intensively studied recently, but relatively little research has focused on the mycobiome and virome. This up-to-date review retrospectively summarizes the lung microbiome's history, composition, and function. We focus on the interaction of the lung microbiome with the oropharynx and gut microbiome and emphasize the role it plays in the innate and adaptive immune responses. More importantly, we focus on multiple respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD), fibrosis, bronchiectasis, and pneumonia. The impact of the lung microbiome on coronavirus disease 2019 (COVID-19) and lung cancer has also been comprehensively studied. Furthermore, by summarizing the therapeutic potential of the lung microbiome in lung diseases and examining the shortcomings of the field, we propose an outlook of the direction of lung microbiome research.

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

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

Extracellular traps are evident in Romanowsky-stained smears of bronchoalveolar lavage from children with non-cystic fibrosis bronchiectasis

BACKGROUND AND OBJECTIVE

The importance of extracellular traps (ETs) in chronic respiratory conditions is increasingly recognized but their role in paediatric bronchiectasis is poorly understood. The specialized techniques currently required to study ETs preclude routine clinical use. A simple and cost-effective ETs detection method is needed to support diagnostic applications. We aimed to determine whether ETs could be detected using light microscopy-based assessment of Romanowsky-stained bronchoalveolar lavage (BAL) slides from children with bronchiectasis, and whether the ETs cellular origin could be determined.

METHODS

Archived Romanowsky-stained BAL slides from a cross-sectional study of children with bronchiectasis were examined for ETs using light microscopy. The cellular origin of individual ETs was determined based on morphology and physical contact with surrounding cell(s).

RESULTS

ETs were observed in 78.7% (70/89) of BAL slides with neutrophil (NETs), macrophage (METs), eosinophil (EETs) and lymphocyte (LETs) ETs observed in 32.6%, 51.7%, 4.5% and 9%, respectively. ETs of indeterminate cellular origin were present in 59.6% of slides. Identifiable and indeterminate ETs were co-detected in 43.8% of slides.

CONCLUSION

BAL from children with bronchiectasis commonly contains multiple ET types that are detectable using Romanowsky-stained slides. While specialist techniques remain necessary to determining the cellular origin of all ETs, screening of Romanowsky-stained slides presents a cost-effective method that is well-suited to diagnostic settings. Our findings support further research to determine whether ETs can be used to define respiratory endotypes and to understand whether ETs-specific therapies may be required to resolve airway inflammation among children with bronchiectasis.

Respiratory Comorbidities Associated with Bronchiectasis in Patients with Common Variable Immunodeficiency in the USIDNET Registry

BACKGROUND

Bronchiectasis is a major respiratory complication in patients with common variable immunodeficiency (CVID) and is associated with recurrent pulmonary infections. However, it is unclear whether other infections or non-infectious respiratory conditions are related to its development.

OBJECTIVE

To identify respiratory comorbidities associated with bronchiectasis in patients with CVID.

METHODS

A total of 1470 CVID patients enrolled in the USIDNET registry were included in a cross-sectional analysis. The primary outcome of our study was to determine the clinical characteristics and other respiratory conditions associated with respiratory comorbidities and physician-reported bronchiectasis.

RESULTS

One hundred ninety-seven CVID patients were noted to have bronchiectasis (13.4%). Affected patients were significantly older than patients without bronchiectasis (median age 54 years vs. 49 years, p = 0.0004). These patients also had lower serum IgA (13 mg/dL IQR 60 mg/dL vs. 28.4 mg/dL IQR 66 mg/dL, p = 0.000). Notably, chronic rhinosinusitis (OR = 1.69 95%CI 1.05-2.75), sinusitis (OR = 2.06 95%CI 1.38-3.09), pneumonia (OR = 2.70 95%CI 1.88-3.88), COPD (OR = 2.66 95%CI 1.51-4.67), and interstitial lung disease (OR = 2.34 95%CI 1.41-3.91) were independently associated with the development of bronchiectasis in this population.

CONCLUSION

These data suggest that lower and upper respiratory infections, chronic lower airway disease, and interstitial lung diseases are independently associated with bronchiectasis in CVID patients. Further study into predisposing conditions related to the development of bronchiectasis in CVID patients may allow prediction and early intervention strategies to prevent the development of this complication.

Predictive power of chest radiography for infectious or inflammatory lung disease

OBJECTIVE

Children frequently present with chronic cough, recurrent respiratory infections, and dysphagia. These symptoms are poor predictors of significant inflammatory lung disease, such as from chronic aspiration. Bronchoalveolar lavage (BAL) is the gold standard for identification of lung infection and airway inflammation but is expensive and requires sedation. Chest X-rays (CXR) are inexpensive, low-radiation tests that do not require sedations and can document findings associated with infectious or inflammatory lung disease. The accuracy of CXR to predict or exclude infectious or inflammatory lung disease has not been directly evaluated and is unknown.

METHODS

Retrospective cohort of all pediatric patients who underwent FFB with BAL within 2 weeks of a CXR. Blinded CXR images reviewed for findings consistent with inflammatory disease by two senior pediatric radiologists. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for CXR to identify significant inflammation and/or infection on BAL were calculated.

RESULTS

Three hundred and forty-four subjects included. Two hundred and sixty-three had positive CXR (77%), 183 had inflammatory BAL (53%), and 110 had infection (32%). The sensitivity of CXR changes for BAL inflammation, infection, and either inflammation or infection was 84.7, 90.9, and 85.3, respectively. The PPV of CXR was 58.9, 38.0, and 59.7. The NPV of CXR was 65.0, 87.5, and 66.3.

CONCLUSIONS

Although CXR are inexpensive, do not require sedation, and are of low radiation dose, the ability of an entirely normal CXR to exclude active inflammatory or infectious lung disease is limited.

Chronic Cough and Causes in Children

Coughing is a natural means to clear the airway [...].

Yardstick for managing cough. Part 2: in children

Nationwide statistics in the United States and Australia reveal that cough of undifferentiated duration is the most common complaint for which patients of all ages seek medical care in the ambulatory setting. Management of chronic cough is one of the most common reasons for new patient visits to respiratory specialists. Because symptomatic cough is such a common problem and so much has been learned about how to diagnose and treat cough of all durations but especially chronic cough, this 2-part yardstick has been written to review in a practical way the evidence-based guidelines most of which have been developed from high-quality systematic reviews on how best to manage cough of all durations in adults, adolescents, and children. Chronic cough in children is often benign and self-limiting. Using established and validated protocols and specific pointers (clues in history, findings on examination) can aid the clinician in identifying causes when present and improve outcomes. In this manuscript, part 2 of the 2-part series, we provide evidence-based, expert opinion recommendations on the management of chronic cough in the pediatric patient (<14 years of age).

Clinical features and pathogen distributions of microbiological-based protracted bacterial bronchitis in children of different ages in Northeast China

Background

Protracted bacterial bronchitis (PBB) is often diagnosed clinically according to chronic wet cough, which can be resolved by appropriate antibiotics. Though rarely performed in PBB diagnosis, bacterial cultures by sputum or bronchoalveolar lavage (BAL) fluid can provide etiological features, which may be different in western countries and different areas of China. This study aimed to investigate the clinical and etiological features and outcomes in children of different ages with PBB in northeast China.

Methods

We retrospectively analyzed children diagnosed with PBB by positive BAL fluid or sputum bacterial cultures between 2017 and 2021. Children were divided into three age groups: <1 year (infants), 1-5 years (younger children), and ≥6 years (older children). Clinical characteristics, chest radiographic findings, bronchoscopy findings, microbiological findings, treatment strategies, and outcomes were reviewed and compared among the age groups. Factors associated with remission during follow-up were examined using logistic regression.

Results

A total of 45 children with PBB were included, consisting of 24 (53.3%) infants. The infants were often boys and had a shorter cough duration, a lower proportion of expectoration, a greater proportion of wheezing, and less bronchial wall thickening on high-resolution computed tomography compared to older children (P < 0.05). No significant differences were found among the age groups regarding macroscopic findings, except for a higher proportion of tracheobronchial malacia in infants than in older children (P = 0.013). The most commonly cultured bacteria were Haemophilus influenzae (42.2%), followed by Streptococcus pneumoniae (22.2%) and Klebsiella pneumoniae (20.0%). Compared to older children, infants had a higher remission (P = 0.009) and relatively lower relapse rates (P = 0.059). Short duration of cough (OR = 0.58, 95% CI: 0.34-0.99, P = 0.046) and absence of recurrent cephalosporins before diagnosis (OR = 0.05, 95% CI: 0.00-0.73, P = 0.028) were associated with remission.

Conclusions

Infants are more prone to PBB, with increased wheezing. Gram-negative bacilli infections are common in infants in northeast China. Older children with PBB should be carefully assessed, treated and followed up, particularly those with long duration of cough and poor response to antibiotic treatments.

Immunomodulators Containing Epicor, Colostrum, Vitamin D, Zinc, Lactobacilli and Bifidobacterium Reduce Respiratory Exacerbations in Children and Adults with Chronic Pulmonary Diseases

(1) Background: A number of studies have demonstrated the connection between developing or exacerbating chronic respiratory diseases in adults and children. However, still, few studies focus on reducing exacerbations via immunomodulation. (2) Methods: In this pilot study, a total of 25 pediatric and adult patients with bronchial asthma (BA) and chronic obstructive pulmonary disease (COPD)/persistent bacterial bronchitis (PBB) were included, administered over-the-counter (OTC) immunomodulators and followed up for 6 or 12 months. (3) Results: We observed a decrease in the frequency of exacerbations with slight improvements in functional respiratory indicators in adults on their second and third visits and a reduced number of exacerbations and improved spirometry indices in children with BA, although exacerbations requiring hospital admission remained at a similar rate. (4) Conclusions: We confirmed that the number of exacerbations of underlying chronic respiratory disease in adults and children could be reduced after the administration of OTC immunomodulators, probably by optimizing the immune resistance to common viral infections.

Protocol for CLASSIC PBB: comparison of lower airway sampling strategies in children with protracted bacterial bronchitis

BACKGROUND

Protracted bacterial bronchitis (PBB) is an endobronchial infection and a the most common cause of chronic wet cough in young children. It is treated with antibiotics, which can only be targeted if the causative organism is known. As most affected children do not expectorate sputum, lower airway samples can only be obtained by bronchoalveolar lavage (BAL) samples taken during flexible bronchoscopy (FB-BAL). This is invasive and is therefore reserved for children with severe or relapsing cases. Most children with PBB are treated empirically with broad spectrum antibiotics. CLASSIC PBB will compare the pathogen yield from two less invasive strategies with that from FB-BAL to see if they are comparable.

METHODS

131 children with PBB from four UK centres referred FB-BAL will be recruited. When attending for FB-BAL, they will have a cough swab and an induced sputum sample obtained. The primary outcome will be the discordance of the pathogen yield from the cough swab and the induced sputum when compared with FB-BAL. Secondary outcomes will be the sensitivity of each sampling strategy, the success rate of the induced sputum in producing a usable sample and the tolerability of each of the three sampling strategies.

DISCUSSION

If either or both of the two less invasive airway sampling strategies are shown to be a useful alternative to FB-BAL, this will lead to more children with PBB having lower airway samples enabling targeted antibiotic prescribing. It would also reduce the need for FB, which is known to be burdensome for children and their families.

TRIAL REGISTRATION NUMBER

ISRCTN79883982.

Non-Cystic Fibrosis Bronchiectasis in Pediatric Age: A Case Series in a Metropolitan Area of Northern Italy

Non-cystic fibrosis bronchiectasis is an emergent disease characterized by endobronchial suppuration, dilated airways with neutrophilic inflammation and chronic wet cough due to recurrent lower airway infections. A regular clinical follow-up and adequate management of exacerbations are essential to reduce symptoms and the worsening of lung injury. We report a retrospective study comprising 15 children and adolescents with NCFB followed in our hospital center of pediatric pulmonology. We retrospectively analyzed the main comorbidities associated with the presence of NCFB, the radiological aspect associated with the different etiologies and the therapeutic approach used. We also emphasized the importance of an effective preventive strategy to reduce and prevent pulmonary exacerbations.

Childhood 'bronchitis' and respiratory outcomes in middle-age: a prospective cohort study from age 7 to 53 years

BACKGROUND

Chronic bronchitis in childhood is associated with a diagnosis of asthma and/or bronchiectasis a few years later, however, consequences into middle-age are unknown.

OBJECTIVE

To investigate the relationship between childhood bronchitis and respiratory-related health outcomes in middle-age.

DESIGN

Cohort study from age 7 to 53 years.

SETTING

General population of European descent from Tasmania, Australia.

PARTICIPANTS

3202 participants of the age 53-year follow-up (mean age 53, range 51-55) of the Tasmanian Longitudinal Health Study cohort who were born in 1961 and first investigated at age 7 were included in our analysis.

STATISTICAL METHODS

Multivariable linear and logistic regression. The association between parent reported childhood bronchitis up to age 7 and age 53-year lung conditions (n=3202) and lung function (n=2379) were investigated.

RESULTS

Among 3202 participants, 47.5% had one or more episodes of childhood bronchitis, classified according to severity based on the number of episodes and duration as: 'non-recurrent bronchitis' (28.1%); 'recurrent non-protracted bronchitis' (18.1%) and 'recurrent-protracted bronchitis' (1.3%). Age 53 prevalence of doctor-diagnosed asthma and pneumonia (p-trend <0.001) and chronic bronchitis (p-trend=0.07) increased in accordance with childhood bronchitis severities. At age 53, 'recurrent-protracted bronchitis' (the most severe subgroup in childhood) was associated with doctor-diagnosed current asthma (OR 4.54, 95% CI 2.31 to 8.91) doctor-diagnosed pneumonia (OR=2.18 (95% CI 1.00 to 4.74)) and, paradoxically, increased transfer factor for carbon monoxide (z-score +0.51 SD (0.15-0.88)), when compared with no childhood bronchitis.

CONCLUSION

In this cohort born in 1961, one or more episodes of childhood bronchitis was a frequent occurrence. 'Recurrent-protracted bronchitis', while uncommon, was especially linked to multiple respiratory outcomes almost five decades later, including asthma, pneumonia and raised lung gas transfer. These findings provide insights into the natural history of childhood 'bronchitis' into middle-age.

A multi‐disciplinary approach to chronic cough in children

Objectives

(1) To highlight the important causes of chronic and recurrent cough in children. (2) To discuss multidisciplinary approach to management of chronic/recurrent pediatric cough.

Methods

Review of scholarly articles, guidelines, expert panels via PubMed and Google Scholar.

Conclusion

Chronic cough (CC) in children is mainly attributed to persistent bacterial bronchitis, asthma, nonspecific cough, and gastroesophageal reflux disease (GERD) symptoms. A multi‐disciplinary approach is cost‐effective and aids with earlier diagnosis and appropriate treatment. Congenital or acquired narrowing of the subglottis is the leading ENT cause for recurrent croup (RC) in children. Laryngeal cleft‐type 1 is commonly seen in children with recurrent aspiration and CC. Children are usually referred to pulmonologists for wet cough not responding to treatment. Eosinophilic esophagitis (EoE) and GERD should be considered in the differential diagnosis of CC in children with both respiratory symptoms and failure to thrive.

Level of Evidence: 2a

Is secondary tracheomalacia associated with airway inflammation and infection?

BACKGROUND

Recurrent lower respiratory tract infections are among the most prevalent symptoms in secondary tracheomalacia due to mediastinal vascular anomalies (MVAs). It is not known whether this condition could result in persistent lower respiratory tract inflammation and subclinical infection.

METHODS

A retrospective study was performed on records of children with tracheomalacia due to MVAs and recurrent respiratory infections who underwent computed tomography scan, bronchoscopy, and bronchoalveolar lavage (BAL) as part of their clinical evaluation.

RESULTS

Thirty-one children were included in the study: 21 with aberrant innominate artery, four with right aortic arch, one with double aortic arch, and five with aberrant innominate artery associated with right aortic arch. Cytological evaluation of bronchoalveolar lavage fluid showed increased neutrophil percentages and normal lymphocyte and eosinophil proportions. Microorganism growth was detected in 13 BAL samples, with a bacterial load ≥10⁴ colony-forming units/mL in eight (25.8%) of them. Most isolates were positive for Haemophilus influenzae. Bronchiectasis was detected in four children, all with BAL culture positive for H. influenzae. Four patients underwent MVA surgical correction and 27 conservative management, i.e., respiratory physiotherapy in all and high-dose amoxicillin/clavulanic acid (40 mg/kg/day) for 2-4 weeks in those with significant bacterial growth. There was an excellent outcome in most of them.

CONCLUSIONS

Neutrophilic alveolitis is detectable in secondary tracheomalacia but is associated with a clinically significant bacterial load only in a quarter of the patients. Caution should be used regarding inappropriate antibiotic prescriptions to avoid the emergence of resistance, whilst airway clearance maneuvers and infection preventive measures should be promoted.

Diagnostic Accuracy of Nasopharyngeal Swab Cultures in Children Less Than Five Years with Chronic Wet Cough

Background: It is necessary to find a non-invasive and accurate procedure to predict persistent bacterial bronchitis (PBB) causative organisms and guide antibiotic therapy. The study objective was to compare the diagnostic accuracy of nasopharyngeal swab cultures with bronchoalveolar lavage (BAL) cultures in children with PBB. Methods: Nasopharyngeal swab and BAL fluid specimens were collected and cultured for bacterial pathogens prospectively from less than five-year-old children undergoing flexible bronchoscopy for chronic wet cough. Results: Of the 59 children included in the study, 26 (44.1%) patients had a positive BAL bacterial culture with neutrophilic inflammation. Prevalence of positive cultures for any of the four common respiratory pathogens implicated in PBB (Moraxella catarrhalis, Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae) was significantly higher (p = 0.001) in NP swabs compared to BAL fluids (86.4% and 44.1% of PBB cases, respectively). NP swab cultures for any of the four main bacterial pathogens had 85% (95% CI: 65–96%) and 48% (95% CI: 31–66%) sensitivity and specificity of detecting PBB, respectively. Positive and negative predictive values were 56% (95% CI: 47–65%) and 80% (95% CI: 60–91%), respectively. In conclusion, in children less than 5 years of age with chronic wet cough (PBB-clinical), a negative NP swab result reduces the likelihood of lower airway infection; however, a positive NP swab does not accurately predict the presence of lower airway pathogens. Flexible bronchoscopy should be considered in those with recurrent PBB-clinical or with clinical pointers of central airway anomalies.

Clinical and research priorities for children and young people with bronchiectasis: an international roadmap

The global burden of children and young people (CYP) with bronchiectasis is being recognised increasingly. They experience a poor quality of life and recurrent respiratory exacerbations requiring additional treatment, including hospitalisation. However, there are no published data on patient-driven clinical needs and/or research priorities for paediatric bronchiectasis.

Parent/patient-driven views are required to understand the clinical needs and research priorities to inform changes that benefit CYP with bronchiectasis and reduce their disease burden. The European Lung Foundation and the European Respiratory Society Task Force for paediatric bronchiectasis created an international roadmap of clinical and research priorities to guide, and as an extension of, the clinical practice guideline.

This roadmap was based on two global web-based surveys. The first survey (10 languages) was completed by 225 respondents (parents of CYP with bronchiectasis and adults with bronchiectasis diagnosed in childhood) from 21 countries. The parent/patient survey encompassed both clinical and research priorities. The second survey, completed by 258 health practitioners from 54 countries, was limited to research priorities.

The two highest clinical needs expressed by parents/patients were: having an action management plan for flare-ups/exacerbations and access to physiotherapists. The two highest health practitioners’ research priorities related to eradication of airway pathogens and optimal airway clearance techniques. Based on both surveys, the top 10 research priorities were derived, and unanimous consensus statements were formulated from these priorities.

This document addresses parents'/patients' clinical and research priorities from both the parents'/patients' and clinicians' perspectives and will help guide research and clinical efforts to improve the lives of people with bronchiectasis.

This document is an international roadmap on parents’/patients’ clinical and research priorities from both the parents’/patients’ and clinicians’ perspectives to help guide research and clinical efforts to improve the lives of people with bronchiectasishttps://bit.ly/3xoonwi

Task Force report: European Respiratory Society guidelines for the management of children and adolescents with bronchiectasis

There is increasing awareness of bronchiectasis in children and adolescents, a chronic pulmonary disorder associated with poor quality-of-life for the child/adolescent and their parents, recurrent exacerbations and costs to the family and health systems. Optimal treatment improves clinical outcomes. Several national guidelines exist, but there are no international guidelines.The European Respiratory Society (ERS) Task Force for the management of paediatric bronchiectasis sought to identify evidence-based management (investigation and treatment) strategies. It used the ERS standardised process that included a systematic review of the literature and application of the GRADE approach to define the quality of the evidence and level of recommendations.A multidisciplinary team of specialists in paediatric and adult respiratory medicine, infectious disease, physiotherapy, primary care, nursing, radiology, immunology, methodology, patient advocacy and parents of children/adolescents with bronchiectasis considered the most relevant clinical questions (for both clinicians and patients) related to managing paediatric bronchiectasis. Fourteen key clinical questions (7 "Patient, Intervention, Comparison, Outcome" [PICO] and 7 narrative) were generated. The outcomes for each PICO were decided by voting by the panel and parent advisory group.This guideline addresses the definition, diagnostic approach and antibiotic treatment of exacerbations, pathogen eradication, long-term antibiotic therapy, asthma-type therapies (inhaled corticosteroids, bronchodilators), mucoactive drugs, airway clearance, investigation of underlying causes of bronchiectasis, disease monitoring, factors to consider before surgical treatment and the reversibility and prevention of bronchiectasis in children/adolescents. Benchmarking quality of care for children/adolescents with bronchiectasis to improve clinical outcomes and evidence gaps for future research could be based on these recommendations.

Study Protocol for Preventing Early-Onset Pneumonia in Young Children Through Maternal Immunisation: A Multi-Centre Randomised Controlled Trial (PneuMatters)

Background: Preventing and/or reducing acute lower respiratory infections (ALRIs) in young children will lead to substantial short and long-term clinical benefits. While immunisation with pneumococcal conjugate vaccines (PCV) reduces paediatric ALRIs, its efficacy for reducing infant ALRIs following maternal immunisation has not been studied. Compared to other PCVs, the 10-valent pneumococcal-Haemophilus influenzae Protein D conjugate vaccine (PHiD-CV) is unique as it includes target antigens from two common lower airway pathogens, pneumococcal capsular polysaccharides and protein D, which is a conserved H. influenzae outer membrane lipoprotein. Aims: The primary aim of this randomised controlled trial (RCT) is to determine whether vaccinating pregnant women with PHiD-CV (compared to controls) reduces ALRIs in their infants' first year of life. Our secondary aims are to evaluate the impact of maternal PHiD-CV vaccination on different ALRI definitions and, in a subgroup, the infants' nasopharyngeal carriage of pneumococci and H. influenzae, and their immune responses to pneumococcal vaccine type serotypes and protein D. Methods: We are undertaking a parallel, multicentre, superiority RCT (1:1 allocation) at four sites across two countries (Australia, Malaysia). Healthy pregnant Australian First Nation or Malaysian women aged 17-40 years with singleton pregnancies between 27⁺⁶ and 34⁺⁶ weeks gestation are randomly assigned to receive either a single dose of PHiD-CV or usual care. Treatment allocation is concealed. Study outcome assessors are blinded to treatment arms. Our primary outcome is the rate of medically attended ALRIs by 12-months of age. Blood and nasopharyngeal swabs are collected from infants at birth, and at ages 6- and 12-months (in a subset). Our planned sample size (n = 292) provides 88% power (includes 10% anticipated loss to follow-up). Discussion: Results from this RCT potentially leads to prevention of early and recurrent ALRIs and thus preservation of lung health during the infant's vulnerable period when lung growth is maximum. The multicentre nature of our study increases the generalisability of its future findings and is complemented by assessing the microbiological and immunological outcomes in a subset of infants. Clinical Trial Registration: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374381, identifier: ACTRN12618000150246.

Diagnosis and management of protracted bacterial bronchitis: a survey of Chinese pediatricians

BACKGROUND

Protracted bacterial bronchitis (PBB) is a common cause of chronic wet cough in children. However, it is often misdiagnosed and inappropriately treated in clinical practices. This study aims to investigate the current diagnosis and management of PBB among Chinese pediatricians.

METHODS

An electronic questionnaire designed to assess the diagnosis and management of PBB was sent to pediatricians in China.

RESULTS

A total of 1,022 pediatricians completed the questionnaire. Most (68.8%) of the pediatricians diagnosed PBB in compliance with the guidelines, 44.3% and 24.5% of them followed microbiology-based and clinical-based diagnosis criteria, respectively. Only 40.4% of the pediatricians chose amoxicillin-clavulanate as the first-line antibiotic for PBB treatment, 23.7% and 23.5% of them chose third-generation cephalosporins and macrolides, respectively. The majority of pediatricians (75.4%) reported 2-4 weeks of antibiotics course, 19.3% of them prescribed a shorter course and 5% of them selected a longer course. Only 26.3% of the pediatricians performed combined investigations of chest high-resolution computed tomography scan (c-HRCT), bronchoscopy, and immunological tests for recurrences of PBB. Compared with general pediatricians (GP), pediatric pulmonologists (PP) preferred microbiology-based diagnosis criteria, prescribed more amoxicillin-clavulanate, and performed more investigations for recurrent patients (P<0.05).

CONCLUSIONS

The majority of Chinese pediatricians diagnosed PBB in compliance with guidelines. However, the reasonable antibiotics applications and the investigations for recurrent PBB need to be improved.

Half of children with recurrent or chronic wet cough before three years of age were symptom-free by age seven

AIM

We aimed to study the natural course of recurrent episodic and chronic wet cough in preschool children, the proportion and age of resolution, and risk factors for persistent symptoms.

METHODS

Parents of children with recurrent or chronic wet cough who had attended the outpatient clinic before the age of three years during 2010-2013 at Stavanger University Hospital, Norway, answered a questionnaire regarding clinical symptoms and current medication at a follow-up in 2017-2018.

RESULTS

We invited 840 children to participate, and parents consented for 348 (41.4%) of the children. At the first outpatient visit, 171 children (58.8%) had recurrent episodic and 120 (41.2%) had chronic wet cough. At follow-up at a median age of 82 months, 57.0% in both groups were symptom-free, and 9.4% with episodic cough and 13.3% with chronic cough had more than mild symptoms. During the last 12 months prior to the survey, 27.2% with episodic cough and 18.6% with chronic cough had used inhaled corticosteroids.

CONCLUSION

Half of the preschool children with recurrent episodic or chronic wet cough outgrew their symptoms by the median age of seven years, but one in four still used inhaled corticosteroids.

Duration of initial antibiotic course is associated with recurrent relapse in protracted bacterial bronchitis

Protracted bacterial bronchitis (PBB) is the leading cause of chronic wet cough in young children from developed countries. Despite its high prevalence there is a paucity of evidence to inform the optimal duration of treatment leading to variation in practice. Relapse of chronic cough is common and recurrent PBB (>3 episodes in 12 months) is associated with a future diagnosis of bronchiectasis. We investigated the factors associated with any relapse (≥1 episode in 12 months) and recurrent PBB in 66 children. No factor was significantly associated with any relapse. Duration of initial antibiotic treatment was the only factor significantly associated with recurrent PBB. Those who received antibiotics for 6 weeks antibiotics were less likely to develop recurrent PBB than those who received for 2 weeks (p=0.046). This is the first study to show an association between duration of initial antibiotic course and therefore future bronchiectasis. Prospective studies are needed to investigate this association.

Comparative genomic analysis identifies X-factor (haemin)-independent Haemophilus haemolyticus: a formal re-classification of 'Haemophilus intermedius'

The heterogeneous and highly recombinogenic genus Haemophilus comprises several species, some of which are pathogenic to humans. All share an absolute requirement for blood-derived factors during growth. Certain species, such as the pathogen Haemophilus influenzae and the commensal Haemophilus haemolyticus, are thought to require both haemin (X-factor) and nicotinamide adenine dinucleotide (NAD, V-factor), whereas others, such as the informally classified 'Haemophilus intermedius subsp. intermedius', and Haemophilus parainfluenzae, only require V-factor. These differing growth requirements are commonly used for species differentiation, although a number of studies are now revealing issues with this approach. Here, we perform large-scale phylogenomics of 240 Haemophilus spp. genomes, including five 'H. intermedius' genomes generated in the current study, to reveal that strains of the 'H. intermedius' group are in fact haemin-independent H. haemolyticus (hiHh). Closer examination of these hiHh strains revealed that they encode an intact haemin biosynthesis pathway, unlike haemin-dependent H. haemolyticus and H. influenzae, which lack most haemin biosynthesis genes. Our results suggest that the common ancestor of modern-day H. haemolyticus and H. influenzae lost key haemin biosynthesis loci, likely as a consequence of specialized adaptation to otorhinolaryngeal and respiratory niches during their divergence from H. parainfluenzae. Genetic similarity analysis demonstrated that the haemin biosynthesis loci acquired in the hiHh lineage were likely laterally transferred from a H. parainfluenzae ancestor, and that this event probably occurred only once in hiHh. This study further challenges the validity of phenotypic methods for differentiating among Haemophilus species, and highlights the need for whole-genome sequencing for accurate characterization of species within this taxonomically challenging genus.

Outcomes of protracted bacterial bronchitis in children: A 5-year prospective cohort study

BACKGROUND AND OBJECTIVE

Long-term data on children with PBB has been identified as a research priority. We describe the 5-year outcomes for children with PBB to ascertain the presence of chronic respiratory disease (bronchiectasis, recurrent PBB and asthma) and identify the risk factors for these.

METHODS

Prospective cohort study was undertaken at the Queensland Children's Hospital, Brisbane, Australia, of 166 children with PBB and 28 controls (undergoing bronchoscopy for symptoms other than chronic wet cough). Monitoring was by monthly contact via research staff. Clinical review, spirometry and CT chest were performed as clinically indicated.

RESULTS

A total of 194 children were included in the analysis. Median duration of follow-up was 59 months (IQR: 50-71 months) post-index PBB episode, 67.5% had ongoing symptoms and 9.6% had bronchiectasis. Significant predictors of bronchiectasis were recurrent PBB in year 1 of follow-up (OR_adj = 9.6, 95% CI: 1.8-50.1) and the presence of Haemophilus influenzae in the BAL (OR_adj = 5.1, 95% CI: 1.4-19.1). Clinician-diagnosed asthma at final follow-up was present in 27.1% of children with PBB. A significant BDR (FEV₁ improvement >12%) was obtained in 63.5% of the children who underwent reversibility testing. Positive allergen-specific IgE (OR_adj = 14.8, 95% CI: 2.2-100.8) at baseline and bronchomalacia (OR_adj = 5.9, 95% CI: 1.2-29.7) were significant predictors of asthma diagnosis. Spirometry parameters were in the normal range.

CONCLUSION

As a significant proportion of children with PBB have ongoing symptoms at 5 years, and outcomes include bronchiectasis and asthma, they should be carefully followed up clinically. Defining biomarkers, endotypes and mechanistic studies elucidating the different outcomes are now required.

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.

Sphingosine signaling dysfunction in airway cells as a potential contributor to progression from protracted bacterial bronchitis to bronchiectasis in children

AIM

Protracted bacterial bronchitis (PBB) is considered a potential precursor to bronchiectasis (BE) in some children. We previously showed that alveolar macrophages (AM) from children with PBB or BE have a similar significant defect in phagocytic capacity, with proinflammatory associations. We hypothesized that the mechanisms responsible for this defect involve dysregulation of the sphingosine-1-phosphate (S1P) signaling pathway, as we have found in adult inflammatory lung diseases.

METHOD

We employed a Custom TaqMan OpenArray to investigate gene expression of S1P-generating enzymes: sphingosine kinases (SPHK) 1/2, S1P phosphatase 2 (SGPP2), S1P lyase 1 (SGPL1), S1P receptors (S1PR) 1/2/4/5; proinflammatory cytokines TNF-α (TNF) and IFNγ (IFNG), the cytotoxic mediator granzyme B (GZMB), and inflammasomes AIM2 and NLRP3, in bronchoalveolar lavage from 15 children with BE, 15 with PBB and 17 age-matched controls, and determined association with clinical/demographic variables and airway inflammation.

RESULT

Significantly increased expression of S1PR1, S1PR2, and SPHK1 was noted in PBB and BE AM vs controls with increased SGPP2 only in PBB. TNF, IFNG, AIM2, and NLRP3 were significantly increased in both disease groups with increased GZMB only in PBB. There were no significant differences in the expression of any other S1P-related mediator between groups. There were significant positive associations between Haemophilus influenzae growth and expression of S1PR1 and NLRP3; between S1PR1 and S1PR2, NLRP3 and IFNG; between S1PR2 and AIM2, SPHK1, and SPHK2; and between SPHK1 and GZMB, IFNG, AIM2, and NLRP3.

CONCLUSION

Children with PBB and BE share similar S1P-associated gene expression profiles. AM phagocytic dysfunction and inflammation in these children may occur due to dysregulated S1P signaling.

Bronchiectasis in Primary Antibody Deficiencies: A Multidisciplinary Approach

Bronchiectasis, the presence of bronchial wall thickening with airway dilatation, is a particularly challenging complication of primary antibody deficiencies. While susceptibility to infections may be the primary factor leading to the development of bronchiectasis in these patients, the condition may develop in the absence of known infections. Once bronchiectasis is present, the lungs are subject to a progressive cycle involving both infectious and non-infectious factors. If bronchiectasis is not identified or not managed appropriately, the cycle proceeds unchecked and yields advanced and permanent lung damage. Severe symptoms may limit exercise tolerance, require frequent hospitalizations, profoundly impair quality of life (QOL), and lead to early death. This review article focuses on the appropriate identification and management of bronchiectasis in patients with primary antibody deficiencies. The underlying immune deficiency and the bronchiectasis need to be treated from combined immunology and pulmonary perspectives, reflected in this review by experts from both fields. An aggressive multidisciplinary approach may reduce exacerbations and slow the progression of permanent lung damage.

Update on protracted bacterial bronchitis in children

BACKGROUND

Chronic cough is a common symptom in children and protracted bacterial bronchitis (PBB) is one of the causes of chronic cough. However, the understanding of this disease remains limited. The present study aims to update PBB in children.

METHODS

The clinical data of children with PBB from 2014 to 2018 were retrospectively analyzed, and PBB clinical features of published studies were summarized. Electronic databases were searched in May 2019. Clinical studies were included in the present study. Reviews were undertaken in duplicate.

RESULTS

Totally 712 cases were analyzed in this study, including 52 cases in our center and 660 cases from 14 studies. In the 52 cases, 88.5% of patients with PBB were less than 6 years old and all of them complained of wet cough. Three cases were confirmed with laryngomalacia, and microbiologically-based-PBB were identified in 13 cases (9 Streptococcus pneumonia, 3 Staphylococcus aureus, and 1 Pseudomonas aeruginosa). Twenty cases were completely remitted after treatment. In the 14 studies, the patients with PBB were typically younger than 3 years old, accompanying wheezing and airway malacia. Co-infection was common in most western cases, Streptococcus pneumonia, Haemophilus influenza and Moraxella catarrhalis were the top three pathogens. Symptoms were improved in most patients, whereas some cases with comorbidities required prolonged antibiotics treatment.

CONCLUSIONS

PBB is common in male infants with chronic wet cough and accompanied by wheezing and airway deformities. Most cases are clinically diagnosed PBB in China and microbiologically-based-PBB is common in western countries. Co-infection could be found, Streptococcus pneumoniae and Haemophilus influenza were the most frequent etiology in China and western countries, respectively. Patients with comorbidities may need extended antibiotics treatment for more than 2 weeks.

Developing a core outcome set for children with protracted bacterial bronchitis

Background

Protracted bacterial bronchitis (PBB) is a chronic endobrochial infection and a leading cause of chronic wet cough in children. There is an urgent need for a randomised controlled trial to investigate the optimal treatment but there is no core outcome set (COS) to inform choice of outcomes. A COS is a standardised set of outcomes representing the minimum that should be measured and reported in clinical trials of a specific condition. We have developed a COS for PBB.

Methods

Potential core outcomes were collated from a systematic review, interviews with parents and a clinician survey. A two-round Delphi survey of healthcare professionals identified which outcomes had consensus for inclusion. The final COS was agreed at a consensus meeting of parent representatives and clinicians.

Results

20 outcomes were identified for the Delphi survey. After two rounds, 10 reached consensus. These were combined and edited at the consensus meeting into the final six: 1) Resolution of cough assessed using a cough score/diary recorded daily by parent(s) during treatment; 2) relapse of chronic wet cough and/or cumulative antibiotic treatment during ≥12 months follow-up; 3) change in child's quality of life (parent-proxy reporting for young children); 4) emergence of antibiotic resistance; 5) development of bronchiectasis diagnosed on clinically indicated computed tomography scans; and 6) microbiological clearance of identified respiratory pathogen if samples readily available.

Conclusions

We have developed a COS for PBB which will reduce the outcome heterogeneity and bias of future clinical trials, as well as promoting comparison between studies.

A core outcome set for protracted bacterial bronchitis in children that will reduce outcome heterogeneity and bias in future clinical trials and promote meta-analysishttp://bit.ly/2PDQvHL