This project aims to assess the relationship between the microbiome and virome composition, the immune responses, and the respiratory health of children with protracted bacterial bronchitis (PBB). In addition, we aim to evaluate how the standard treatment with azithromycin interacts with the components of the microbiome, virome and immune biomarkers.
Protracted Bacterial Bronchitis (PBB) is an often underestimated disease, characterized by a persistent cough for more than four weeks, without other significant underlying symptoms. While generally treatable, it can lead to complications such as recurrent infections and airway damage (bronchiectasis). The reasons why some children develop PBB or subsequent complications while others do not remain unclear. Recent research suggests that an impaired immune response and microbiota dysbiosis may play a key role. This study aims to analyze the microbial and viral composition of the airways in children with PBB, its relationship with inflammation, and the effects of azithromycin. Oropharyngeal swabs will be collected from up to 160 children \<5 years old diagnosed with PBB at UZA in a longitudinal setup during one year. At each routine consultation (five in total) and during an exacerbation episode, three oropharyngeal swabs will be collected from each child. The three swabs will be used to: (1) determine the microbiome composition using next-generation sequencing, (2) identify the virome composition using multiplex qPCR or similar approaches, and (3) quantify immune biomarkers (RNA and protein-level) and culture microbial isolates. These findings will help to better understand the role of the airway microbiome in young children with PBB and identify microorganisms that may have a pathogenic or protective role. Ultimately, this knowledge may contribute to the development of new and effective diagnostics and treatments for PBB from an early age.
Study Type
OBSERVATIONAL
Enrollment
160
Antwerp University Hospital
Edegem, Belgium
Analysis of respiratory microbiome composition
Description: Analysis of microbiome communities in airway samples will be performed using amplicon or shotgun sequencing to determine relative microbial abundances (in percentages) as the unit of measure, coupled with the use of bioinformatic tools for community structure analysis.
Time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
Prevalence of respiratory viruses
Description: Detection of respiratory viruses from airway samples using RT-qPCR. Unit of Measure: percentage of positive samples (in percentages).
Time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
Immune biomarkers profiling in airway samples
Immunological profiling will be performed in airway samples by determining (1) cytokine concentrations based on protein-level analysis such as ELISA (pg/mL) and/or (2) differential gene expression based on RNA analysis (log fold-change or similar metric).
Time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
Correlates of respiratory microbiome
Description: Microbial profiles will be associated with demographic, epidemiological and clinical data collected through standardized questionnaires and clinical assessments to determine relevant correlates. Unit of Measure: Statistical association measure (e.g., correlation coefficients or similar).
Time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
Correlates of Protracted Bacterial Bronchitis
PBB events will be associated with demographic, epidemiological and clinical data collected through standardized questionnaires and clinical assessments to determine relevant correlates. Unit of Measure: Effect estimates (odds/prevalence/hazard ratios or similar).
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Time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations