Procalcitonin levels in children with bloodstream infections caused by different species: a cohort study

Abstract Background: Timely diagnosis and accurate identification of the causative microorganism in sepsis is crucial in order to offer directed treatment and increase survival rates. Previous studies have aimed to identify biomarkers that could potentially predict blood culture positivity in patients with bacteremia; however, most of the research has been performed in adult populations. The aim of this study were to analyze procalcitonin levels in confirmed bloodstream infections by species in children and assess its utility in immunocompromised patients. Methods: We included children who met the diagnostic criteria for sepsis, with PCT levels collected within a 72-hour period prior to obtaining a blood culture. Kruskal-Wallis test was used to compare differences among groups. Receiver-operating characteristic curves were used to evaluate PCT cut-offs. Results: 120 patients were included, mean age of 55 months. Subjects with immunodeficiency mean PCT was 26.68 mcg/L, compared to 8.78 in immunocompetent hosts. Subjects with Gram-negative bacilli (GNB) had the highest mean PCT levels (18.2 ± 34.2). The difference among microorganisms was significant. Sensitivity and specificity were 78% and 53% for Gram-positive cocci, 60.9% and 33.3% for GNB, and 75% with 25% for yeasts. Subgroup analysis showed 87.5% sensitivity and 16.7% specificity of PCT for predicting GNB blood culture in immunodeficiency children. Conclusions: PCT could be considered as a surrogate biomarker in immunocompromised children and a viable tool to differentiate etiology by species. Key words: Procalcitonin; Sepsis; Bacterial sepsis