Microbiological and clinical characteristics of Enterococcus faecium bloodstream infections in pediatric patients: A Tertiary Care Center Experience.

Background: Enterococcus faecium has emerged as a significant cause of nosocomial bloodstream infections (BSIs) in pediatric patients, particularly in high-risk populations with underlying chronic or complex medical conditions. Increasing rates of antimicrobial resistance, including vancomycin resistance and high-level aminoglycoside resistance (HLAR), pose additional clinical challenges. This study aimed to characterize the clinical presentation, microbiological features, and outcomes of E. faecium BSIs in a tertiary-care pediatric hospital. Methods: We conducted a retrospective, observational, single-center study over a six-year period (January 2019– December 2025) at Department of Women’s and Children’s Health, University Hospital of Padua. Children aged under 18 years with E. faecium bacteremia were included. Demographic, clinical, and microbiological data were collected, including antimicrobial susceptibility profiles, presence of underlying comorbidities and appropriateness of empirical and targeted therapy. Results: From 2019 to 2025, 32 pediatric E. faecium bloodstream infections were identified (peak in 2021, 34%). Median age was 18 months (IQR: 8–106 months). All patients had underlying comorbidities, mainly hematological disease (38%), liver disease (31%), and solid organ transplantation (25%). Recent healthcare exposure was frequent (97% hospitalization ≤90 days; 53% recent PICU admission), and 84% had received antibiotics in the previous 15 days. Invasive devices were almost universal (97%), particularly central venous catheters (91%). Fever occurred in 90% and toxic appearance in 38%. During sepsis, 41% required respiratory support, 16% inotropes and 6.3% renal replacement therapy. Final diagnoses were mainly intra-abdominal infection–associated sepsis (59%) and catheter-associated bloodstream infection (CLABSI) (28%). Blood-culture resistance profiles demonstrated high rates of multidrug resistance: ampicillin 92%, VREfm 52% (Vancomycin-resistant Enterococcus faecium), HLAR 74%, with no linezolid resistance detected. Colonization with E. faecium was documented in 40%, matching the bloodstream isolate resistance pattern in 70%. At 28 days, 34% were discharged, 50% remained hospitalized, and 9.4% died, but infection-attributable mortality was 3.1%. Conclusions: E. faecium, particularly VREfm, is a major nosocomial threat in pediatric settings. Invasive infections mainly affect medically fragile children with extensive healthcare exposure and are associated with multidrug resistance and prolonged hospitalization. Limited susceptibility profiles restrict therapeutic options, with linezolid and daptomycin representing key definitive treatments. Overall outcomes were acceptable, although prolonged illness and sustained antimicrobial use remain problematic. Optimal management requires prompt culture-guided therapy, multidisciplinary care, and strong antimicrobial stewardship to preserve last-line agents. Prospective multicenter studies are needed to refine risk stratification, prevention strategies, and future treatment approaches.