Clinical-Use-Associated Decrease in Susceptibility of Vancomycin-Resistant Enterococcus faecium 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.

Saponins increase susceptibility of vancomycin-resistant enterococci to antibiotic compounds

“…The currently used antibiotics for VRE-related infections are linezolid, daptomycin, and tigecyclin, but data that address their effi cacy are rare and the tolerability remains problematic [3]. Resistance against these last-line antibiotics occurred only at rare intervals, but do exist [9][10][11][12][13].…”

Comparison of Testing Methods for Detection of Decreased Linezolid Susceptibility Due to G2576T Mutation of the 23S rRNA Gene in Enterococcus faecium and Enterococcus faecalis

“…Clinical resistance to linezolid is associated with a G2576T mutation in domain V of 23S rRNA genes of Enterococcus, and the level of linezolid resistance is directly related to the number of 23S rRNA genes containing this mutation (11,15). Both laboratory and clinical strains of E. faecium with linezolid MICs of 4 g/ml have been shown to carry the G2576T mutation (10,14). Accurate detection by susceptibility testing methods of decreased susceptibility due to G2576T mutation in one or two genes is necessary since this can be a prelude to higher levels of linezolid resistance associated with extensive use of the antibiotic (14).…”

“…Both laboratory and clinical strains of E. faecium with linezolid MICs of 4 g/ml have been shown to carry the G2576T mutation (10,14). Accurate detection by susceptibility testing methods of decreased susceptibility due to G2576T mutation in one or two genes is necessary since this can be a prelude to higher levels of linezolid resistance associated with extensive use of the antibiotic (14).…”

“…Both laboratory and clinical strains of E. faecium with linezolid MICs of 4 g/ml have been shown to carry the G2576T mutation (10,14). Accurate detection by susceptibility testing methods of decreased susceptibility due to G2576T mutation in one or two genes is necessary since this can be a prelude to higher levels of linezolid resistance associated with extensive use of the antibiotic (14).In this study we compared the performance of five different susceptibility testing methods, E-test, disk diffusion, Vitek 2 system, MicroScan WalkAway broth microdilution, and agar dilution, for the detection of decreased linezolid susceptibility of Enterococcus faecalis and E. faecium due to presence of the G2576T mutation.Strain selection. collected during this period.…”

VRE fecal colonization/infection in cancer patients

“…Although most patients respond to therapy and the attributable mortality remains low, the emergence of resistance to linezolid is of considerable concern. 4 The organisms remain susceptible to new agents such as daptomycin. 5 Our data indicate that hospitalized patients with hematological malignancies and HSCT recipients are at greater risk of developing VRE infections than patients with solid tumors.…”