Low selection of topoisomerase mutants from strains of Escherichia coli harbouring plasmid-borne qnr genes

Abstract

Topoisomerase mutants are rarely selected by ciprofloxacin and moxifloxacin from strains harbouring qnr. This suggests that the quinolone resistance-determining region domains are protected from quinolones by the Qnr protein and consequently other mechanisms are developed to acquire a further step of fluoroquinolone resistance.