Zingiber officinale-mediated zinc oxide nanoparticles: antimicrobial activity against multidrug-resistant bacteria

The fight against infectious diseases has transformed over the past century with the emergence of multidrug-resistant bacteria, where pathogens that exhibit resistance to multiple antibiotic classes leading to significant challenges to modern medicine. Zingiber officinale is well-documented to exhibit diverse biological activities, including strong antioxidant, antimicrobial, and anti-neuroinflammatory effects. Zinc oxide nanoparticles can be synthesized cost-effectively and are widely utilized in biomedical applications, including their use as anticancer agents and drug-delivery systems, as well as for their intrinsic antibacterial and anti-inflammatory properties. In this study, we aimed to take a combinatorial approach to investigate the antimicrobial effects of Z. officinale zinc oxide nanoparticles (ZnO NPs) against pathogenic bacteria with varying drug resistance profiles. Bioactive molecules of Z. officinale confirmed via Gas Chromatography-Mass Spectroscopy analysis. Characterization of ZnO NPs was performed by Ultraviolet-visible (UV-Vis) spectrophotometry, Zetasizer analyser, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction crystallography (XRD), and Scanning Electron Microscopy (SEM). Furthermore, the antimicrobial activities of zinc oxide nanoparticles, Z. officinale extract, and Z. officinale–mediated ZnO NPs were evaluated against pathogenic microorganisms, including Bacillus cereus ATCC 7064, methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis ATCC 29212, Listeria monocytogenes Scott A ATCC 49594, Uropathogenic Escherichia coli UTI89, Pseudomonas aeruginosa ATCC 27853, and carbapenem-resistant Klebsiella pneumoniae strains CRKP-239, CRKP-682, and CRKP-692. The zeta sizer analysis showed that the Z. officinale-ZnO NPs had an average size of 89.09 nm, while the unloaded ZnO NPs measured 67.86 nm, confirming that both formulations were within the nanoscale range. ZnO NPs exhibited a well-defined zone of inhibition and low MIC values between 3.25 and 50 µg/ml. Biogenic ZnO NPs (42.42 ± 43.95 at 12.5 ± 100 µg/ml respectively) and Z. officinale extract (32.75 ± 40.22 at 12.5 ± 100 µg/ml respectively) revealed antioxidant potential. Thus, our results demonstrate that Z. officinale ZnO NPs demonstrate antimicrobial activity against a wide range of gram-positive and gram-negative multidrug-resistant pathogenic bacteria and can be further researched to target multidrug-resistant bacterial infections.