Clinical-Use-Associated Decrease in Susceptibility of Vancomycin-Resistant <i>Enterococcus faecium</i> to Linezolid: a Comparison with Quinupristin-Dalfopristin

Abstract

The susceptibility of 135 vancomycin-resistant Enterococcus faecium bacteremic isolates to linezolid and quinupristin-dalfopristin was determined. All were susceptible to linezolid, while 88% were susceptible to quinupristin-dalfopristin prior to the clinical use of the drugs at our hospital. More than 6 months after their clinical use, a decrease in susceptibility was noted for only linezolid at 83%. This was related in part to a single G2576U gene mutation in domain V of the 23S rRNA gene.