Antibacterial and Antibiofilm Activity of Zinc Oxide Quantum Dots against Methicillin-resistant Staphylococcus aureus

Antimicrobial resistance occurs mostly through the ineffective and unauthorized use of antibiotics in both the environment and health care. Biofilms are a new target in the search for new antibacterial agents. Here, the sol-gel method is used to produce zinc oxide quantum dots (ZnO-QDs). The ZnO-QDs show yellow emission at 526 nm under 360 nm excitation. After that, the ability of ZnO-QDs as an antibacterial and antibiofilm agent against methicillin-resistant Staphylococcus aureus (MRSA) is examined. The 100 samples are collected from patients with hospital-acquired infections between December 2020 and October 2021 from Imamen Kadhmiyan Teaching Hospital in Baghdad (Iraq). Out of these 100 samples, 63 are S. aureus and 20 out of 63 are MRSA. The minimum inhibitory concentration assay demonstrates the antibacterial activity of ZnO-QDs on MRSA strains. Also, results show that 80, 5, and 15% of isolated MRSA strains produce strong, moderate, and weak or very weak biofilm, respectively. The effect of ZnO-QDs on strong and moderate biofilms reveal that QDs could also inhibit and destroy biofilm produced by MRSA. In addition, the antibiofilm effect of ZnO-QDs is greater than their antibacterial effect. Generally, this work offers new insights into the development of antibacterial and antibiofilm nanomaterials.