Antimicrobial Activity of Zinc Oxide Nanoparticles and Allium sativum Extract Against Pathogenic Escherichia coli and Staphylococcus aureus Isolates

Abstract

Background: The increasing trends in antimicrobial resistance (AMR) have continued to pose a global public health concern. This rapid emergence and spread of antimicrobial resistance have necessitated the exploration of innovative approaches to combat microbial infections. This study investigated the potential of enhancing antimicrobial properties through the synergistic effect of zinc oxide nanoparticles (ZnO NPs) and Allium Sativum (garlic) extracts against Escherichia Coli and Staphylococcus aureus
Methods: Zinc oxide nanoparticles (ZnO NPs), were synthesised using the sol-gel method and later synergised with extracts of Allium sativum. Formation of ZnO NPs was confirmed using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and UV-visible spectrophotometry methods. Similarly, these methods were also used in formed Allium Sativum extracts as well as in ZnO NPs and garlic acid combined product. The antimicrobial activity of the nanoparticles against Staphylococcus aureus and Escherichia coli isolates were determined using Kirby Bauer disc and well diffusion methods.
Results: The average size of ZnO NPs in the present study is 40.96nm with a percentage crystallinity of 58.30%. The minimum inhibitory concentrations (MIC) of ZnO NPs ranged from 5 to 0.312 mg/ml. The antimicrobial assay of both ZnO NPs and crude Allium Sativum extracts showed a concentration-dependent effect. The zones of inhibition for ZnO NPs ranged from 18mm to 20mm±2.5, crude Allium Sativum extracts 8mm to 14.2mm±2, while the synergistic effect of ZnO NPs and crude Allium Sativum extracts was more effective with zones of inhibition ranging from 40mm±2 and 42mm±3.5 against Enteropathogenic Escherichia coli and Staphylococcus aureus, respectively. Antimicrobial assays revealed that the drug combination exhibited a significantly enhanced inhibitory effect against tested isolates by 35% with reduced minimum inhibitory concentrations (MICs) by 50% compared with individual treatments.
Conclusion: Our findings confirm the promising use of zinc oxide nanoparticles (ZnO NPs) in treating pathogenic Staphylococcus aureus and Enteropathogenic Escherichia coli (EPEC) bacteria that zinc oxide nanoparticles (ZnO NPs) could be a possible alternative antibiotic. These results highlight the powerful potential of combining nanotechnology with natural products as alternative antimicrobial agents.