Abstract

Background: Today, the presence of antibiotic-resistant bacteria has become a global problem. Thus, finding new antibacterial compounds is considered a key solution for public health. The aim of this study was to investigate the antibacterial properties of Arnebia euchroma, Chelidonium majus L., Calendula officinalis L., Malva sylvestris L., Brassica oleracea L. var italic, and Myrtus communis extracts plus propolis and to evaluate the synergistic interaction of them together and with some antibiotics against several nosocomial pathogenic bacteria.
Methods: The minimum inhibitory concentration was determined using microdilution broth. Well diffusion agar was used to determine the growth inhibition zone. Finally, an electron microscope image was taken at a sub-MIC concentration.
Results: All used extracts had an inhibitory effect on the bacteria. The combination of the extracts with each other and with antibiotics had a synergistic effect on inhibiting bacteria. Electron microscopy images displayed the degradation of the bacterial cell wall structure and cell deformation during treatment with propolis, B. oleracea, and M. communis.
Conclusion: Tested extracts can be used as treatment options for bacterial infections. Further in vivo and clinical studies are recommended.

Key words: propolis; antibacterial; Staphylococcus aureus; Escherichia coli; Brassica oleracea; Methicillin-resistant S. aureus