Resistance/fitness trade-off is a barrier to the evolution of MarR inactivation mutants in Escherichia coli.

ABSTRACT:

Background

Mutations that inactivate MarR reduce susceptibility to ciprofloxacin and competitive growth fitness in Escherichia coli. Both phenotypes are caused by overexpression of the MarA regulon, which includes the AcrAB-TolC drug efflux pump.

Objectives

We asked whether compensatory evolution could reduce the fitness cost of MarR-inactivating mutations without affecting resistance to ciprofloxacin.

Methods

The cost of overexpressing the AcrAB-TolC efflux pump was measured independently of MarA overexpression. Experimental evolution of MarR-inactive strains was used to select mutants with increased fitness. The acquired mutations were identified and their effects on drug susceptibility were measured.

Results

Overexpression of the AcrAB-TolC efflux pump was f

SUBMITTER: Praski Alzrigat L 

PROVIDER: S-EPMC7729382 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature