Alternative vanHAX promoters and increased vanA-plasmid copy number resurrect silenced glycopeptide resistance in Enterococcus faecium.

ABSTRACT:

Background

Vancomycin variable enterococci (VVE) are van-positive isolates with a susceptible phenotype that can convert to a resistant phenotype during vancomycin selection.

Objectives

To describe a vancomycin-susceptible vanA-PCR positive ST203 VVE Enterococcus faecium isolate (VVESwe-S) from a liver transplantation patient in Sweden which reverted to resistant (VVESwe-R) during in vitro vancomycin exposure.

Methods

WGS analysis revealed the genetic differences between the isolates. Expression of the van-operon was investigated by qPCR. Fitness and stability of the revertant were investigated by growth measurements, competition and serial transfer.

Results

The VVESwe-R isolate gained high-level vancomycin (MIC >256 mg/L) and teicoplanin resistance (MIC = 8 mg

SUBMITTER: Wagner TM 

PROVIDER: S-EPMC7953315 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature