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Updated: Aug 19, 2026

Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance
Published on: May 2, 2018
[Mechanisms of plasmid-mediated resistance to quinolones]
José Manuel Rodríguez-Martínez1
1Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla, Spain. jmrodriguez@us.es
Abstract:
Quinolone resistance is caused mainly by chromosomal mutations in gram negative bacteria. In 1998, plasmid-mediated resistance to quinolones in clinical isolates was first reported in a Klebsiella pneumoniae strain. Locus qnr (quinolone resistance) was responsible of the quinolone resistance in this plasmid. qnr codes a protein whose function is protect both DNA-girase and topoisomerase IV from these antimicrobials. Moreover, qnr is located in an integron-like structure upstream of qacEDelta y sul1. A review of the information obtained in the last years about this mechanism of resistance was performed.
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