Protracted Bacterial BronchitisNCT07255430
Airway Microbiome of Patients With Protracted Bacterial Bronchitis
An observational study of Protracted Bacterial Bronchitis, run by University Hospital, Antwerp at 1 site in Belgium.
Trial summary
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). Read more about this study
- Who is it for?
- Ages Up to 5 years
- Conditions the study is for
- Protracted Bacterial Bronchitis
- How many people
- 160 participants
- Where
- 1 siteBelgium
- Study dates
- 7 Jan 2026to Jan 2029
- How long will I take part?
- 12 Months
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Up to 5 years
- All sexes
- No healthy volunteers
- Child
Study population: Children under five years old diagnosed with PBB.
Who may be able to join
- Children with PBB diagnosis according to case definition
- Consent form signed by parents or legal guardians
Who cannot join
- Comorbidities (HIV, asthma, chronic obstructive pulmonary disease, diabetes)
- Have had serious illnesses (meningitis, pneumonia, bacteremia, empyema, etc) in the previous three months, identified only at the time of enrollment.
- Have chronic respiratory conditions at the time of enrollment (non-PBB bronchiectasis not caused by PBB, CF, allergy, etc.).
- Having received mechanical ventilation.
- Having been hospitalized or used antibiotics in the previous three months at the time of enrollment.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Belgium1 site, 1 recruiting
- Recruiting
Antwerp University Hospital
Edegem, 2650
Kim Van Hoorenbeeck, Prof. dr., +3238213000, kim.vanhoorenbeeck@uza.be
Kim Van Hoorenbeeck, Prof. dr.
About this study
Official title: Interaction Between Microbiome, Virome and Host Immunity Response in the Context of Protracted Bacterial Bronchitis
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.
Read the detailed description
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.
- Conditions
- Protracted Bacterial Bronchitis
- Keywords
- cough, Protracted Bacterial Bronchitis, microbiome
- Medical subject headings
- Cough
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Participants with Protracted bacterial bronchitis diagnostic | Children under five years old who attend pediatric outpatient visits or well-child visits at University Hospital Antwerp (UZA) and are diagnosed with Protracted bacterial bronchitis. |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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).
Measured: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
Secondary outcomes (3)
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).
Measured: 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).
Measured: 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).
Measured: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Dec 2025
- Study start7 Jan 2026
- Primary completionJan 2028 (estimated)
- Study completionJan 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Protracted Bacterial BronchitisStudies of the same condition, open and under way.
- More trials run by University Hospital, AntwerpThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 160 participants (estimated)
- Target duration
- 12 Months
Sponsor and investigators
- Lead sponsor
- University Hospital, Antwerp
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Kim Van Hoorenbeeck, Prof. dr., Principal investigator, University Hospital, AntwerpIrina Spacova, Prof. dr. ir., Principal investigator, Universiteit Antwerpen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07255430
- Sponsor's protocol ID
- BUN B3002025000069
- Status last verified
- Sep 2025
- First submitted
- 1 Oct 2025
- Last updated
- 19 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The metadata of participants in the study will be made available in a restricted access repository. For samples and data sharing, the researchers will work with the legal department to establish Material/Data Transfer Agreements. Sequencing data are available at the European Nucleotide Archive. Physical samples are their origin will be stored at the decentral hub of the Antwerp biobank.
Study at a glance
From the registry record, last updated by the sponsor on 19 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Interaction Between Microbiome, Virome and Host Immunity Response in the Context of Protracted Bacterial Bronchitis
- ClinicalTrials.gov ID
- NCT07255430
- Acronym / sponsor ID
- BUN B3002025000069
- Conditions
- Protracted Bacterial Bronchitis
- Keywords
- cough, Protracted Bacterial Bronchitis, microbiome
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 160 participants (estimated)
- Lead sponsor
- University Hospital, AntwerpUniversity, hospital or other
- Study start
- 7 Jan 2026 (actual)
- Primary completion
- Jan 2028 (estimated)
- Study completion
- Jan 2029 (estimated)
- First posted
- 1 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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 design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 12 Months
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Participants with Protracted bacterial bronchitis diagnostic | – | –Children under five years old who attend pediatric outpatient visits or well-child visits at University Hospital Antwerp (UZA) and are diagnosed with Protracted bacterial bronchitis. |
Who may qualify
- Ages
- Up to 5 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
- Study population
- Children under five years old diagnosed with PBB.
Key inclusion criteria (2 listed)
- Children with PBB diagnosis according to case definition
- Consent form signed by parents or legal guardians
Key exclusion criteria (5 listed)
- Comorbidities (HIV, asthma, chronic obstructive pulmonary disease, diabetes)
- Have had serious illnesses (meningitis, pneumonia, bacteremia, empyema, etc) in the previous three months, identified only at the time of enrollment.
- Have chronic respiratory conditions at the time of enrollment (non-PBB bronchiectasis not caused by PBB, CF, allergy, etc.).
- Having received mechanical ventilation.
- Having been hospitalized or used antibiotics in the previous three months at the time of enrollment.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Analysis of respiratory microbiome composition
Time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
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.
Prevalence of respiratory viruses
Time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
Description: Detection of respiratory viruses from airway samples using RT-qPCR. Unit of Measure: percentage of positive samples (in percentages).
3 secondary outcomes
Immune biomarkers profiling in airway samples
Time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
Correlates of respiratory microbiome
Time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
Correlates of Protracted Bacterial Bronchitis
Time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 Mar 2026.
- Individual participant dataSharing planned: Yes. The metadata of participants in the study will be made available in a restricted access repository. For samples and data sharing, the researchers will work with the legal department to establish Material/Data Transfer Agreements. Sequencing data are available at the European Nucleotide Archive. Physical samples are their origin will be stored at the decentral hub of the Antwerp biobank.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Kim Van Hoorenbeeck, Prof. dr. principal investigator
University Hospital, Antwerp
Irina Spacova, Prof. dr. ir. principal investigator
Universiteit Antwerpen
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Protracted Bacterial Bronchitis, run by University Hospital, Antwerp at 1 site in Belgium.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 19 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Kim Van Hoorenbeeck, Prof. dr. (+3238213000, kim.vanhoorenbeeck@uza.be), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Analysis of respiratory microbiome composition (time frame: Baseline, 3 months, 6 months, 9 months, 12 months and during exacerbations). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Mar 2026.