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Published on: January 3, 2020
Effect of Ruta graveolens Extract on the Major Virulence Factors in Methicillin Resistant Staphylococcus aureus
Shahinda Rezk1, Omar Alqabbasi2, Asmaa Ramadan3,4
1Microbiology Department, Medical Research Institute, Alexandria University, Alexandria, Egypt.
Purpose:
Rising Antibiotic Resistance has put the world in real threat. Methicillin resistant Staphylococcus aureus (MRSA), is a predominant cause of suppurative chronic skin and soft-tissue infections. Novel insights have focused the light on plant extracts. In this study, Ruta graveolens ethanolic active extract was tested for its potential anti-virulence activities in MRSA.
Materials And Methods:
A total of 100 MRSA strains causing skin and soft tissue infections were isolated and antibiotic susceptibility testing was done. Ability to form biofilm was tested phenotypically. Furthermore, the antimicrobial activity of Ruta graveolens was evaluated followed by detection of its Minimum inhibitory concentration (MIC). The inhibitory activity of this extract on biofilm formation was investigated. Afterwards, we investigated its effect on the transcription of biofilm-related genes and mecA gene.
Results:
All tested isolates were sensitive to Vancomycin and Linezolid while high resistance was noted with both Fusidic acid (83%) and Gentamicin (68%). (83%) of the isolates were biofilm producers. Ruta graveolens extract showed strong antimicrobial activity against the MRSA strains with MIC 0.78 mg/mL. At subinhibitory concentration (1/2 MIC), the extract had high biofilm inhibitory effects with mean inhibition (70%). Moreover, transcriptional analysis results showed that the mean percentages of inhibition in expression of mecA, icaA and icaD genes were 52.3%, 34.8% and 33.7%, respectively, in which all showed statistically significant difference (p ≤ 0.05).
Conclusion:
The current study proposes the ability of Ruta graveolens extract to reduce the biofilm formation and antibiotic resistance of MRSA through downregulation of some biofilm forming genes and mecA gene which confers resistance to B-lactam antibiotics. This may decrease our reliance on antibiotics and improve our ability to effectively treat biofilm-related skin and soft-tissue infections caused by MRSA.
Insights
Ruta graveolens extract combats antibiotic-resistant MRSA by inhibiting biofilm formation and downregulating key resistance genes. This natural approach offers a promising alternative for treating stubborn skin infections.
Area of Science:
- Microbiology
- Pharmacology
- Natural Products
Background:
- Antibiotic resistance, particularly Methicillin-resistant Staphylococcus aureus (MRSA), poses a significant global health threat.
- MRSA is a primary cause of challenging chronic skin and soft-tissue infections.
- Plant-derived extracts are increasingly explored for antimicrobial and anti-virulence properties.
Purpose of the Study:
- To evaluate the anti-virulence potential of an ethanolic extract from Ruta graveolens against MRSA.
- To investigate the extract's antimicrobial activity, biofilm inhibition, and effect on virulence gene expression in MRSA.
Main Methods:
- Isolated and characterized 100 MRSA strains from skin infections.
- Determined antibiotic susceptibility, biofilm formation, and Minimum Inhibitory Concentration (MIC) of Ruta graveolens extract.
- Assessed the extract's effect on biofilm formation and the transcriptional levels of biofilm-related genes (icaA, icaD) and the mecA gene.
Main Results:
- Ruta graveolens extract demonstrated potent antimicrobial activity against MRSA with an MIC of 0.78 mg/mL.
- The extract significantly inhibited biofilm formation by 70% at sub-inhibitory concentrations.
- Downregulation of mecA, icaA, and icaD gene expression was observed by 52.3%, 34.8%, and 33.7%, respectively (p ≤ 0.05).
Conclusions:
- Ruta graveolens extract effectively reduces MRSA biofilm formation and antibiotic resistance.
- The extract's anti-virulence mechanism involves downregulating biofilm-associated and mecA genes.
- This natural extract presents a viable strategy to manage MRSA skin infections and reduce antibiotic reliance.
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