Electrokinetic and Antibiofilm Effects of Silver Nanoparticles Combined with Imipenem Against multidrug-resistant of Klebsiella pneumoniae

Antimicrobial resistance has been recognized as a global public health problem, contributing to high rates of morbidity, mortality and costs associated with infectious diseases. In 2024, the World Health Organization identified carbapenem-resistant Klebsiella pneumoniae (K. pneumoniae) as the pathogen of greatest importance for research and development of new drugs. In this context, the work analyzes the association of silver nanoparticles with the carbapenem antibiotic Imipenem (IPM) in a multidrug-resistant (MDR) clinical isolate of K. pneumoniae, in comparison to susceptible isolate. The silver nanoparticles (AgNPs) were synthesized using the bottom-up method and characterized through UV-Vis spectroscopy, dynamic light scattering, infrared spectroscopy and X-ray diffraction. Antimicrobial susceptibility tests were carried out on planktonic cells and biofilms. The pH, zeta potential and electrophoretic mobility analysis of the bacteria and antimicrobials was carried out at concentrations identical to those used in the antimicrobial susceptibility assay, aiming to understand the mechanism of internalization and synergistic potentiation. The combination of imipenem (IPM) and AgNPs exhibited an inhibitory effect on planktonic cells and biofilms of the MDR clinical isolate of K. pneumoniae. The surfaces of the bacterial isolates and antimicrobials displayed a negative surface charge. From these results and insights into bacterial electrokinetics, an anionic influx of the antimicrobials through the porin channels can be proposed, leading to increased permeability. The association of silver nanoparticles with IPM was shown to restore the efficacy of the carbapenem antibiotic against MDR K. pneumoniae.