Liver Transplantation Is Associated with Vancomycin-Resistant Enterococcus Bacteremia at an Academic Medical Center in Loma Linda, California, 2016–2023

Background: Loma Linda University Medical Center has had rates of hospital-onset vancomycin-resistant Enterococcus blood stream infections (HO VRE BSIs) above the statewide rate among major teaching hospitals in California. We sought to identify factors associated with this high rate. Methods: We conducted retrospective case-control studies, first comparing cases of HO VRE BSI with controls with HO vancomycin sensitive Enterococcus BSI. HO BSI was defined as a positive blood culture specimen collected ≥72 h after hospital admission. Inpatients were identified from microbiology records 2016-2023. For each hospitalization complicated by HO BSI, we compared gender, age, prior history of VRE, and specific admission diagnoses. In secondary analysis, we compared liver transplant recipients 2016-2024 with/without HO VRE BSI by the same variables and also by severity of illness, prior biliary interventions, and inpatient antibiotics received within 180 days before transplant. Result: Among 137 cases and 139 controls, age (odds ratio [OR] 1.03; 95% confidence interval [CI] = 1.01-1.04), history of VRE in the past year (13.98; 4.10-47.64), and liver transplant recipient status (3.96; 1.25-12.52) were independently associated with increased odds of HO VRE BSI. Among liver transplant recipients, receipt of piperacillin/tazobactam (1.11; 1.03-1.20) was independently associated with increased odds of HO VRE BSI. Conclusion: The association of HO VRE BSI with liver transplant could explain the higher rate of HO VRE BSI in our institution. These results, in combination with secondary analysis on liver transplant patients, suggest VRE infection control should focus on liver transplant populations and antibiotic stewardship with broad-spectrum antibiotics.