Epidemiology of Vancomycin-Resistant Enterococcus faecium and Enterococcus faecalis Colonization in Nursing Facilities
Elyse Davis, Liam Hicks, Ihsan Ali, Elizabeth Salzman, Joyce Wang, Evan S. Snitkin, Kristen Gibson, Marco Cassone, Lona Mody, Betsy Foxman
Abstract
Abstract Background Vancomycin-resistant Enterococcus faecium and Enterococcus faecalis frequently colonize nursing facility (NF) residents, creating opportunities for vancomycin-resistant Enterococcus (VRE) transmission and dissemination of mobile genetic elements conferring antimicrobial resistance. Most VRE studies do not speciate; our study addresses this lack and compares the epidemiology of E faecium and E faecalis. Methods We enrolled 651 newly admitted patients from 6 different NFs and collected swabs from several body sites at enrollment, 14 days, 30 days, and monthly thereafter for up to 6 months. The VRE were speciated using a duplex polymerase chain reaction. We used multinomial logistic regression models to compare risk factors associated with colonization of E faecium and E faecalis. Results Overall, 40.7% were colonized with E faecium, E faecalis, or both. At enrollment, more participants were colonized with E faecium (17.8%) than E faecalis (8.4%); 3.2% carried both species. Enterococcus faecium was carried twice as long as E faecalis (69 days and 32 days, respectively), but incidence rates were similar (E faecium, 3.9/1000 person-days vs E faecalis, 4.1/1000 person-days). Length of stay did not differ by species among incident cases. Residents who used antibiotics within the past 30 days had a greater incidence of both E faecium (odds ratio [OR] = 2.89; 95% confidence interval [CI], 1.82–4.60) and E faecalis (OR = 1.80; 95% CI, 1.16–2.80); device use was most strongly associated with the incidence of E faecium colonization (OR = 2.01; 95% CI, 1.15–3.50). Conclusions Recent increases in vancomycin-resistant E faecium prevalence may reflect increased device use and longer duration of carriage.