Characterization of community-associated Staphylococcus aureus and evaluation of the antibacterial efficacy of Syzygium aromaticum-derived silver nanoparticles

Staphylococcus aureus , a common bacterium found in the nasal passages of humans, raises significant health risks due to its potential to cause severe infections and its ability to develop antibiotic resistance. This research examines S. aureus strains isolated from human nasal passages and assesses the antibacterial effectiveness of green synthesized silver nanoparticles (AgNPs) against these strains. Biochemical and genotypic characterization identified the strains. PCR tests and agarose gel electrophoresis confirmed the presence of mecA , nuc and pvl genes. Simultaneously, AgNPs were synthesized using Syzygium aromaticum to promote environmental sustainability. Gas Chromatography-Mass Spectrometry (GC-MS) analysis revealed eugenol as the primary phytochemical in S. aromaticum responsible for AgNPs synthesis. Atomic force microscopy (AFM) analysis revealed that the synthesized AgNPs possessed a spherical morphology. In vitro antibacterial assays demonstrated that these AgNPs exhibited significant bactericidal activity against S. aureus isolates, as confirmed by agar well diffusion, MIC determination and further supported by AFM and flow cytometry. These results highlighted the antibacterial potential of green-synthesized AgNPs by showing bacterial morphological changes and cell death. In conclusion, the study highlights the potential of S. aromaticum mediated green synthesized AgNPs as an effective antibacterial agent against antibiotic-resistant community associated S. aureus . These findings support further in vivo investigations to validate their clinical applicability and therapeutic potential. • Collection and characterization of Staphylococcus aureus strains from human nasal passages • Detection of mecA , nuc and pvl genes in S. aureus isolates • Identification of phytochemical compounds in Syzygium aromaticum via GC-MS analysis • Evaluation of antibacterial activity of green-synthesized AgNPs using agar well diffusion and MIC assays • Investigation of antibacterial mechanisms through AFM imaging and flow cytometry analysis