An Optimized Anti-adherence and Anti-biofilm Assay: Case Study of Zinc Oxide Nanoparticles versus MRSA Biofilm
Hefa Mangzira Kemung, Loh Teng‐Hern Tan, Kooi Yeong Khaw, Yong Sze Ong, Chim Kei Chan, Darren Yi Sern Low, Siah Ying Tang, Bey Hing Goh
Abstract
Biofilms form protective layers over bacteria that are associated with a majority of the hospital infections contributing to antibiotic resistance development in susceptible strains. Nowadays, there is a pressing need for developing effective anti-biofilm agents to help address the growing problem of biofilm-producing bacteria associated with antibiotic resistance. In recent years, zinc oxide nanoparticles (ZnO-NPs) has emerged as a prospective candidate for new anti-biofilm agents. The present method paper described an optimized anti-adherence and anti-biofilm assay using ZnO-NPs. The antibiotic-resistant bacteria Methicillin-resistant Staphylococcus aureus (MRSA ATCC4330) and vancomycin were used as the growth control and positive control, respectively. The result showed concentration-dependent anti-adherence and antibiofilm activity. The ZnO-NPs effectively prevented attachment of bacterial cells onto walls of wells with 51.69 ± 2.55% at the highest concentration tested (65.4 µg/mL). ZnO-NPs was also able to break-up 50% pre-formed MRSA biofilm at the lowest concentration of 13.5 µg/mL. Interestingly, ZnO-NPs at lower concentrations demonstrated significantly stronger antibiofilm activity than that of the positive control vancomycin, demonstrating that ZnO-NPs is a promising anti-biofilm agent. This method could be used as a preliminary screening of transition metal oxide nanoparticles as potential anti-adherence and anti-biofilm agents followed by other specific anti-biofilm assays.