In vitro activity of plazomicin and other aminoglycosides against Klebsiella pneumoniae multidrug-resistant strains.

Plazomicin is a new aminoglycoside with broad-spectrum activity against multidrug-resistant strains. The aim of this study was to assess the susceptibility of the K. pneumoniae strains to plazomicin and other aminoglycosides. The activity of plazomicin in combination with ceftazidim-avibactam or meropenem with selected strains was evaluated. The study involved 60 ESβL-positive K. pneumoniae isolates and 50 carbapenemase-positive. The susceptibility to aminoglycosides was tested using the gradient strip. The in vitro activities of plazomicin and ceftazidim-avibactam or meropenem were evaluated using the MTS cross synergy method. Plazomicin exhibited high activity against K. pneumoniae with MICs ranging from 0.19 to 4 µg ml for ESβL-positive strains and from 0.25 to 256 µg ml for carbapenemase-positive strains. No antagonism was identified with any combinations. Plazomicin demonstrated excellent in vitro activity against analyzed strains, suggesting that this antibiotic may be an effective therapeutic option in the treatment of infections caused by MDR K. pneumoniae strains.