MRSA (Methicillin-resistant bacteria Staphylococcus aureus) is the main causative agent of chronic infections associated with biofilms in humans, which are responsible for serious healthcare problems in the world. Biofilm-associated infections are challenging to manage with traditional antibiotic treatments due to the protective nature of a surrounding extracellular matrix. In this research, 16S rDNA of thirty S. aureus strains (isolated from King Faisal Hospital) was sequenced to identify the isolates, and the results showed 98–100% identity with comparable S. aureus from the NCBI database. The isolates were then placed in the NCBI GenBank and assigned the accession numbers from OP363093 to OP363122. Then, we screened ethanolic and methanolic extracts of Rhazya stricta leaves against clinical MRSA isolates to measure their growth inhibition property using MIC and disk diffusion methods. In addition, these extracts were used to measure the degree to which crystal violet inhibited biofilms. HPLC testing revealed 19 constituents including stilbene (resveratrol), quinol, 11 phenolic acids, and 6 flavonoids, and showed that there are differences between the extracts in the element’s number and their amounts. Both extracts showed antimicrobial properties against pathogenic microbes such as MRSA isolates. Extracts from R. stricta displayed potent inhibitory action on biofilms, with inhibition rates extending from 71.5% to 99% and from 26.2% to 98.9% for the ethanolic and methanolic extracts, respectively. R. stricta leaf extracts revealed potent antimicrobial as well as anti-biofilm activities of MRSA isolates and might be a distinct substitute for the prevention and therapy of the pathogen MRSA.













