A new biomarker combination differentiates viral from bacterial infections and helps monitoring response to antibiotics in hospitalized children.

The development of new diagnostic techniques to support the initial clinical evaluation is one of the key strategies to mitigate the inappropriate antibiotic prescription in Pediatrics. We conducted a prospective observational study to test a novel chemiluminescence assay that helps differentiating bacterial and viral infections by combining three host-response proteins (C-reactive protein, TRAIL and IP-10). We enrolled 255 children (age 1-243 months) presenting to a Pediatric Infectious Diseases Unit with fever (60%), cough (22.4%), gastrointestinal symptoms (22%), proven infection (38%). The 22.7% of patients carried at least one comorbidity. The baseline test demonstrated 51% sensitivity and 91% specificity. The diagnostic accuracy was better than traditional biomarkers (C-reactive protein, white blood cell count). Stratifying the analysis by pre-admission antibiotic treatment, naïve patients showed higher sensitivity for bacterial infection (0.70 vs. 0.15), better negative predictive value (0.60 vs. 0.45) and lower error rate (0.24 vs. 0.51). A significant score reduction was observed shortly after starting antibiotic therapy in a subgroup with microbiologically confirmed bacterial diagnosis (mean - 45.12, mean interval = 4 days). We concluded the test could improve infection management in pediatric settings, support initial therapy decision and potentially reduce unnecessary antibiotics. However, its optimal implementation requires a precise definition of the target population.