Using vancomycin-resistant Enterococcus (VRE) rectal swab screening to predict vancomycin resistance in subsequent Enterococcus faecium bacteraemia in high-risk patients

Abstract

In high-risk patients, colonisation with vancomycin-resistant enterococci (VRE) can lead to invasive infections. A retrospective cohort study was done from 2009–2017 at Singapore General Hospital to study the utility of rectal swab screening in predicting vancomycin resistance in subsequent Enterococcus faecium bacteraemia. Prior VRE screening results were available for 274 episodes of E. faecium bacteraemia. 74 (27.0%) screen tests were VRE-positive. 121 (44.2%) bacteraemia episodes were vancomycin-resistant. The specificity of VRE screening in predicting vancomycin resistance of subsequent E. faecium bacteraemia was high (88.9%), regardless of time from screening to bacteraemia, or agar-based screening protocol used. Negative predictive value was highest (92.3%) when screening was done within 48 h of bacteraemia. Sensitivity (47.1%) and positive predictive value (77.0%) were low. In our institution, VRE prevalence is 4.71% among the targeted surveillance group. Patients with VRE bacteraemia received appropriate antibiotics 1 day later than with vancomycin-susceptible enterococcus (VSE) bacteraemia, and had longer hospital stays (48.8 days vs 39.6 days) and higher 30-day mortality (56.2% vs 42.2%). In our hospital, it may be reasonable to withhold empiric anti-VRE antibiotics when the most recent VRE screen is negative. Empiric VRE-active coverage should be considered if a patient was screen-positive within 48 h of bacteraemia onset.