A host signature based on TRAIL, IP-10, and CRP for reducing antibiotic overuse in children by differentiating bacterial from viral infections: A prospective, multicentre cohort study.

Abstract Objectives Identifying infection aetiology is essential for appropriate antibiotic use. Previous studies showed a host-protein signature consisting of TNF-related apoptosis-induced ligand (TRAIL), interferon gamma-induced protein-10 (IP-10), and C-reactive protein (CRP) can accurately differentiate bacterial from viral infections. Methods This prospective, multicentre cohort study titled “AutoPilot-Dx”, aimed to validate signature performance and estimate its potential impact on antibiotic use across a broad paediatric population (>90 days to 18 years) with respiratory tract infections, or fever without source, at emergency departments and wards in Italy and Germany. Infection aetiology was adjudicated by experts based on clinical and laboratory investigations, including multiplex PCR and follow-up data. Results In total, 1140 patients were recruited (2/2017–12/2018), of which 1008 met eligibility criteria (mean age 3.5 years, 41.9% female). Viral and bacterial infections were adjudicated for 628 (85.8%) and 104 (14.2%) children, respectively; 276 patients were assigned an indeterminate reference standard outcome. For the 732 children with reference standard aetiology, the signature discriminated bacterial from viral infections with sensitivity of 93.7% (95% CI, 88.7–98.7), specificity of 94.2% (92.2–96.1), positive predictive value of 73.0% (65.0–81.0), negative predictive value of 98.9% (98.0–99.8), and 9.8% equivocal test results. The signature performed consistently across different patient subgroups and detected bacterial immune response in viral PCR positive patients. Conclusions The findings validate high diagnostic performance of the TRAIL/IP-10/CRP signature in a broad paediatric cohort and support its potential to reduce antibiotic overuse in children with viral infections. Trial registration Clinicaltrials.gov identifier: NCT03052088.