Evaluation of the antibacterial and antibiofilm properties of quercetin against clinical isolates of methicillin-resistant Staphylococcus aureus

Document Type : Original Article


Medical Microbiology and Immunology Department, Faculty of Medicine, Ain Shams University, Egypt


Background:  Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious clinical threat in hospitals. MRSA strains have acquired resistance to nearly every beta-lactam antibiotic because there has been a change in the penicillin-binding protein (PBP2a) encoded by the mec genes. Aim of the work: The objective of this study is to assess quercetin's antimicrobial and antibiofilm capabilities toward MRSA clinical isolates from Ain Shams University Hospitals. Methods: We obtained total of 40 MRSA isolates from the main microbiology lab of Ain Shams University Hospitals. Antimicrobial susceptibility testing and phenotypic identification were carried out, and the MIC of quercetin was determined against 40 MRSA isolates. Sub-MIC quercetin levels were used to determine its impact on biofilm formation. Biofilm formation was significantly reduced by quercetin compared to the control grown in the absence of quercetin. Results: MRSA clinical isolates are susceptible to the antimicrobial and antibiofilm effects of quercetin, and its inhibitory effects increase with its concentration. Conclusion: Quercetin shows antimicrobial and antibiofilm activities against MRSA clinical isolates.


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