In vitro and in vivo persistence of IncN plasmids carrying qnr genes in uropathogenic Escherichia coli isolates.

Objectives: This study aimed to evaluate the persistence of the plasmid-mediated quinolone resistance (PMQR) among uropathogenic Escherichia coli strains grown under or without exposure to subinhibitory concentrations of ciprofloxacin. Based on that, we evaluated the possible spontaneous loss or maintenance of PMQR and the possible appearance of compensatory mutations in gyrA and parC genes.

Methods: Three uropathogenic E.