Who is at risk? Clinical features and a predictive model for 30-day mortality in hematologic patients with enterococcal bloodstream infection

Background Enterococcal bloodstream infection (EBSI) carries high mortality in hematologic patients, yet no prognostic model tailored to this population exists. Methods We retrospectively analyzed 192 hematologic patients (≥14 years) with EBSI admitted between 2014 and 2024. Clinical features, microbiology, treatment, and outcomes were assessed. Candidate predictors for 30-day mortality were selected by LASSO and entered into multivariable logistic regression. A simplified risk score was derived from regression coefficients and internally validated by bootstrap resampling. Results The median patient age was 43 years, and acute leukemia was the predominant underlying disease (72.4%). Enterococcus faecium was the leading pathogen (71.4%), with low vancomycin resistance (1.6%). Most cases (71.9%) occurred as breakthrough infections, mainly during carbapenem therapy, and 72.9% met mucosal barrier injury laboratory-confirmed bloodstream infection criteria. The 14- and 30-day all-cause mortality rates were 13.5% and 22.4%, respectively. Independent predictors of 30-day mortality included age ≥50 years (aOR=2.29, p=0.038), severe graft-versus-host disease (aOR=6.06, p=0.003), septic shock (aOR=30.01, p<0.001). The final predictive model, incorporating these three factors along with pneumonia and high-risk hematologic disease, demonstrated optimal discrimination (AUROC 0.79, 95% CI 0.705–0.867) and calibration. A derived risk score stratified patients into low- (<2 points) and high-risk (≥2 points) groups, with markedly different 30-day mortality (11.3% vs . 39.0%, P<0.001). Conclusions In hematologic patients, EBSIs commonly arise as breakthrough infections despite broad-spectrum antibiotic coverage, most often associated with mucosal barrier injury. Our parsimonious risk score enables early identification of patients at high risk of 30-day mortality to guide timely interventions.