Vancomycin-resistant enterococcus: emergence to endemicity in a tertiary hospital in Singapore

Background

In alignment with national and international recommendations, vancomycin-resistant enterococcus (VRE) surveillance in Singapore General Hospital (SGH) was scaled down and limited to immunocompromised patients from August 2020.

Aim

To describe the evolving epidemiology and risk associations of VRE between 2018 and 2023 in a tertiary hospital in Singapore.

Methods

Inpatients admitted between January 2018 and December 2023 were included. VRE surveillance criteria changed in August 2020 and November 2022. Incidence of any VRE (VRE (all)), VRE from surveillance (VRE (surveillance)), clinical VRE isolates (VRE (clinical)), healthcare-associated VRE infections (HA-VRE (infections)) and bacteraemia (VRE (bacteraemia)) were reviewed. Three case–control studies were conducted. Environmental screening was performed.

Findings

Over the six-year study period there were 5173 patients with VRE, of whom 3141 (60.7%) had HA-VRE, 5157 (99.7%) had E. faecium and 4336 (84%) carried vanA.121 (2.2%) patients had VRE bacteraemia with mortality 50.4%. There were significant changes in incidence of VRE (all), VRE (surveillance) and VRE (clinical) but HA-VRE (infections) and VRE (bacteraemia) remained stable. VRE acquisition was associated with presence of concurrent MRSA (odds ratio: 9.4; 95% confidence interval: 1.3–66.8; P < 0.02), CPE (7.2; 2.0–26.0; P < 0.001), intensive care unit (ICU) admission (6.1; 2.8–13.2; P < 0.001), haemodialysis (4.6; 1.8–12.0; P < 0.001), surgery (3.7; 1.6–8.3; P < 0.001), vancomycin use (28.2; 5.4–146.5; P < 0.001), and metronidazole use (4.4; 1.0–19.0; P = 0.04) in the preceding three months. VRE infection had similar risk associations. In all, 12.5% of environmental samples were VRE positive.

Conclusion

VRE endemic state in SGH is associated with significant patient and environmental VRE burden. VRE acquisition and infection have been associated with co-carriage of MRSA or CPE, vancomycin and metronidazole use, ICU admission and prior surgery. Targeted infection prevention and antimicrobial stewardship programmes may reduce VRE (infections).