Longitudinal (2001–14) analysis of enterococci and VRE causing invasive infections in European and US hospitals, including a contemporary (2010–13) analysis of oritavancin in vitro potency

The objective of this study was to evaluate the prevalence and in vitro susceptibility of enterococci and VRE among bloodstream infections in European and US hospitals over time. Isolates recovered from the blood of infected patients in Europe (72 996) and the USA (67 725) between 2001 and 2014 were included in the prevalence analysis. A subset (2349) collected during 2011–13 was used for the in vitro activity analysis. Enterococcus faecium rates increased in Europe (from 1.4% in 2001 to 4.3% in 2014). These rates also increased in the USA (from 3.0% in 2001 to 5.4% in 2010), with decreasing prevalence (4.6% in 2011 to 3.6% in 2014) in later years. Enterococcus faecalis rates remained stable in Europe, but rose in the USA from 6.9% in 2001 to 8.8% in 2009, declining later (from 7.4% to 5.0%). VRE rates among E. faecalis did not vary in either region, while VRE rates among E. faecium increased in Europe (from 4.7% to 20.3%). US VRE rates among E. faecium increased until 2010 (60.0% in 2001 to 80.7% in 2010), decreasing from 75.1% in 2011 to 68.4% in 2013. Oritavancin demonstrated activity against vancomycin-susceptible E. faecalis (MIC50/90, 0.015/0.06 mg/L; 99.5% susceptible) and vancomycin-resistant E. faecalis (MIC50/90, 0.25/0.5 mg/L). Oritavancin showed MIC50, MIC90 and MIC100 values of 0.03, 0.12 and 0.25 mg/L, respectively, for VanA E. faecium. Rates of E. faecium and VRE increased in Europe. Although still elevated, VRE rates appeared to show a decreasing trend in the USA since 2010. Oritavancin demonstrated activity against enterococci, including VRE.