Vancomycin-resistant enterococcus bacteraemia in an endemic region: clinical features and genomic analysis: a 12-year cohort.

Background: Vancomycin-resistant enterococci (VRE) are important nosocomial pathogens with increasing prevalence worldwide. Hospitals in Jerusalem, Israel are known to have high rates of VRE carriage. However, the clonicity of this pathogen in endemic areas remains unclear.

Methods: The medical files of patients with VRE bacteraemia (N=182) hospitalized in the three major hospitals in Jerusalem between 2009 and 2020 were reviewed. These were compared with 100 patients with vancomycin-susceptible enterococcus (VSE) bacteraemia during the same period, and their clinical and demographic characters were analysed. Whole-genome sequencing (WGS) of the VRE isolates was performed, and the results were analysed considering the demographic, epidemiologic and clinical outcome data.

Results: Patients with VRE bacteraemia had higher rates of central line use, haematologic malignancy and immunosuppression compared with patients with VSE bacteraemia (63% vs 27%, P<0.001; 25% vs 13%, P=0.02; 24% vs 13%, P=0.04, respectively). Patients with VRE bacteraemia had significantly higher 7- and 30-day in-hospital mortality rates (31% vs 18%, P= 0.02; 57% vs 34%, P<0.001, respectively) and a longer mean hospital stay (39 vs 24 days, P=0.005) than patients with VSE bacteraemia. The WGS results of VRE isolates showed diversity rather than endemicity of a single clone. No clones were associated with specific ethnicity, geographical distribution or worse prognosis.

Conclusions: WGS revealed the occurrence of small unrelated outbreaks rather than the expansion of large clusters in Jerusalem. VRE bacteraemia was found in sicker patients, and was associated with higher mortality and longer hospitalization compared with VSE bacteraemia.