Outbreak of vancomycin-resistant Enterococcus faecium starting among patients admitted to a surgical unit in a Swedish county

Abstract

Background Vancomycin-resistant Enterococcus faecium (VRE) is a nosocomial pathogen that causes infection mainly in patients with critical illnesses in intensive care units, severe underlying diseases or weakened immune systems. Intensive pretreatment with antibiotics and the use of urinary catheters also constitute a risk. Due to its hardy nature, the bacterium can survive for long periods in a hospital environment. The aim of this study was to describe the investigation of a sudden increase in VRE cases admitted to the surgical unit at Vrinnevi Hospital in Norrköping, Sweden, and the control measures taken. Methods Faecal cultures from patients admitted to the surgical unit were obtained, and environmental cultures were collected from different locations in patient rooms and medical devices. In addition, screening samples were obtained from units with high-risk patients in Östergötland County. Isolates identified as E. faecium were subjected to antibiotic susceptibility testing. Vancomycin-resistant isolates PCR-positive for the vanA/vanB gene were further analysed with whole-genome sequencing (WGS). Results A total of 35 VRE isolates were found (22 from patients and 13 from the environment). The WGS identified three outbreak clusters, sequence type (ST) 203, ST 1839 and ST 80, and one unique clone (ST 612). The ST 203 clone predominated among VRE cases admitted to the surgical unit. Conclusions With prompt infection control measures, the VRE outbreak was over after approximately four months. To prevent further outbreaks of VRE, active screening, antibiotic stewardship, improved cleaning and hand hygiene, and restriction of multiple-bed rooms is essential.