Multiplex Fluoroquinolone Resistance

Fluoroquinolones represent broad-spectrum antibiotics widely used in clinical medicine and veterinary practice for treatment of both gram-positive and gram-negative bacterial infections. Fluoroquinolone resistance emerges through multiple mechanisms including chromosomal mutations in DNA gyrase (gyrA, gyrB) and topoisomerase IV genes (parC, parE), and plasmid-mediated resistance genes including QnrA, QnrB, QnrS variants and AAC(6′)-Ib-cr. Reduced intracellular fluoroquinolone accumulation through efflux pump overexpression also contributes to resistance. High-level fluoroquinolone resistance typically results from accumulation of multiple resistance mechanisms in single isolates.