Novel host biomarkers could help tailor antibiotic use in children admitted to PICU with pneumonia

Backgrounds: Much research has been carried out to identify novel host biomarkers that can accurately discriminate between bacterial and viral pneumonia in children. However, pneumonia biomarker discovery has not been carried out in a paediatric intensive care unit (PICU) setting, where children have high rates of co-morbidities and relatively indiscriminate administration of antibiotics. This study aims to identify robust novel biomarkers of bacterial pneumonia in this population.

Methods: Children with clinician-diagnosed pneumonia, confirmed on chest radiograph, were recruited from the PICU at the Royal Belfast Hospital for Sick Children between April 2020 and December 2022. Blood plasma was collected and analysed using two O-Link proteomic multiplex proximity extension assays. An independent paediatric intensivist provided a final diagnosis of bacterial, viral or mixed viral and bacterial pneumonia based on clinical data and results from blood culture, bronchoalveolar lavage and sputum.

Results: A total of 27 children were included in the study. The median age was 1.7 (IQR: 0.5-6.8) years and 48% were male. There were 15/27 (56%) cases of viral pneumonia, 9/27 (33%) cases of bacterial ormixed pneumonia and 3/27 (11%) with an unclear aetiology. Bacterial (n=5) and viral (n=13) samples were analysed by O-Link. 126 proteins were found to be differentially expressed between the two groups. Statistical analysis and correlation with published literature identified three promising biomarkers: Resistin, Tissue inhibitor matrix metalloproteinase 1 and Chitinase-3-like protein 1, AUCs are shown below.

Conclusions/Learning Points: Additional biomarkers could help clinicians tailor antibiotic prescribing for pneumonia in the PICU. Technical verification of biomarkers is ongoing in our remaining samples and larger validation studies will be needed to assess the use of biomarkers in this group of patients.