Levofloxacin-Loaded Nanoparticles Decrease Emergence of Fluoroquinolone Resistance in Escherichia coli.

Antimicrobial resistance is a major global health problem that is developed upon exposure of bacteria to antimicrobial agents, and, thus, reducing or eliminating the ability of the currently available antibacterial drugs to eradicate bacterial infections. The aim of the current study was to encapsulate levofloxacin (third generation fluoroquinolones) into chitosan (CS) nanoparticles, to evaluate the antibacterial potency of the nanosized drug, and to characterize the major genetic mutations associated with the exposure of bacteria to the levofloxacin-loaded nanoparticle versus free levofloxacin. Three consecutive mutants were selected by stepwise exposure of one reference and two clinical Escherichia coli isolates to a series of progressively increasing concentrations of levofloxacin and the levofloxacin-loaded nanoparticles.