Prevalence and risk factors of colonisation with vancomycin-resistant Enterococci faecium upon admission to Germany’s largest university hospital

Background: Hospital-acquired infections due to vancomycin-resistant enterococci (VRE) are emerging globally. The aims of our study were to estimate VRE colonisation prevalence in patients upon admission, to determine possible risk factors for VR E. faecium acquisition that already exist in the outpatient setting, and to monitor whether VRE-colonised patients developed a VRE infection during their current hospital stay. Methods: In 2014 and 2015, patients admitted to non-intensive care units were screened for rectal VRE carriage. The study patients filled out a questionnaire on potential risk factors. Analyses were restricted to VR E. faecium carriage. All patients with VRE colonisation were retrospectively monitored for infections with VRE during their current hospital stay. Results: In 4,013 enrolled patients, the VRE colonisation prevalence upon admission was 1.2% (n=48), and colonisation prevalence was 1.1% (n=45) for VR E. faecium. Only one VRE-colonised patient developed an infection with the detection of a VRE, among others. Colonisation with VR E. faecium was associated with current antibiotic use. Risk factors of VR E. faecium colonisation upon admission were increasing age, previous colonisation or infection with multidrug resistant organisms, sampling year 2015, and, within the previous six months, antibiotic exposure, a stay at a rehabilitation center, and a hospital stay. Conclusions: We observed that antibiotic treatment which occurred prior admission influenced VR E. faecium prevalence upon admission. Thus, wise antibiotic use in outpatient settings plays a major role in the prevention of VR E. faecium acquisition.