The study aimed to determine the antibacterial activity of ethanolic extract of Matricaria chamomilla (chamomile), Malva sylvestris, and Capsella bursa-pastoris against Methicillin-resistant Staphylococcus aureus (MRSA) isolated from clinical specimens. Methods: The plants were collected from Ziarat Village, southern heights of Gorgan, and the required parts were separated and then thoroughly dried in the shade. After grinding, extraction was performed by the maceration method. The extract was dried at 37°C for 24 h. A concentration of 50 mg/ml of each extract was obtained in 10 ml 5% dimethyl sulfoxide and sterilized. For the antibacterial assay, agar well diffusion and broth microdilution methods were used. Results: Our results showed no inhibitory effect for the ethanolic extracts of M. sylvestris and C. bursa-pastoris against the MRSA isolates in both antibacterial assays. The chamomile flower extract showed antibacterial activity against the 20 MRSA isolates at 50 and 25 mg/ml concentrations. The extract from chamomile leaves demonstrated an inhibitory effect on the 7 MRSA isolates. The extracts from chamomile flowers demonstrated MIC and MBC at a concentration of 6.25 and 12.5 mg/ml for most MRSA isolates, while these values for the extracts from chamomile leaves were 12.5 and 25 mg/ml for a few MRSA isolates, respectively. Conclusion: In this study, the ethanolic flower extract of chamomile showed significant antibacterial activity against the MRSA isolates. Hence, this extract may be an alternative to antibiotic therapy and a good option to control infections caused by MRSA and pathogenic bacteria.

How to cite this article Sadat S.S., Ahani Azari A. Frequency of Multidrug-Resistant, Extensively Drug-Resistant, and Pandrug-Resistant Phenotypes among Clinical Isolates of Staphylococcus aureus.