Antibacterial and antibiofilm evaluation of biogenic ternary CuO-AgO-MgO nanocomposite against clinical isolates of carbapenem-resistant Klebsiella pneumoniae.

内容摘要

Escalation of antimicrobial resistance amongst Klebsiella pneumoniae (K. pneumoniae) represents a remarkable worldwide health concern. This study reports the green biosynthesis of copper, silver and magnesium oxide trimetallic nanocomposites (CuO-AgO-MgO TNCs) using banana peel extract as a safe and sustainable reducing and stabilizing agent and emphasizes its inhibitory activity against carbapenem-resistant K. pneumoniae (CRKP) strains. The TNCs were characterized by ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis, confirming their crystalline structure (average size 125 nm) and elemental composition (Cu, Ag, Mg, O). Cytotoxicity assessment using WI-38 normal cells showed minimal toxic effect with an IC50 of 193.49 ± 2.85 µg/mL. Antibacterial activity was evaluated against genotypically diverse CRKP strains. Well diffusion assay (WDA) showed inhibition zones of 18-38 mm, while the broth microdilution assay provided minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranging from 8 to 1024 µg/mL and 128 to 2048 µg/mL, respectively. Time-kill assays indicated rapid bacterial growth reduction within 2 h, and antibiofilm assays showed 25-91% inhibition of biofilm formation. The image provided by SEM revealed pronounced morphological alterations in treated bacterial cells. Our findings exhibited biogenic CuO-AgO-MgO TNCs with potent antibacterial and antibiofilm activities against CRKP while showing negligible toxicity towards normal cells, highlighting their potential as a safe and effective alternative antimicrobial strategy.