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

Gilchrist, Francis; Aspey, Mathew; Bowler, Robert; Brodlie, Malcolm; Desai, Seema; Harris, Caroline; Hinton, Emily; Kulkarni, Hemant; Ogbolosingha, Aviva; Sinha, Ian; Solis-Trapala, Ivonne; Stock, Joanne; Carroll, William D

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Mathew Aspey

Robert Bowler

Malcolm Brodlie

Seema Desai

Caroline Harris

Emily Hinton

Hemant Kulkarni

Aviva Ogbolosingha

Ian Sinha

Joanne Stock

William D Carroll


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.

Acceptance Date Oct 27, 2022
Publication Date Nov 21, 2022
Journal BMJ Paediatrics Open
Print ISSN 2399-9772
Publisher BMJ Publishing Group
Pages e001722 - e001722
Publisher URL


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