Citral modulates virulence factors in methicillin-resistant Staphylococcus aureus

Area of Science:

• Microbiology
• Pharmacology
• Infectious Diseases

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) poses significant public health challenges due to high morbidity and mortality.
• Citral, a natural compound, exhibits known antimicrobial properties.
• Developing novel strategies to combat MRSA infections is crucial.

Purpose of the Study:

• To investigate the antimicrobial activity of citral against MRSA.
• To evaluate citral's efficacy in inhibiting MRSA biofilm formation.
• To analyze citral's impact on the modulation of MRSA virulence genes.

Main Methods:

• Determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for citral against MRSA isolates.
• Assessment of citral's synergistic, antagonistic, or indifferent effects with conventional antibiotics.
• Evaluation of citral's antibiofilm activity at different stages of biofilm development.
• Quantitative Polymerase Chain Reaction (qPCR) to analyze the expression of key virulence factor genes (icaA, icaD, seg, sei, eta, etb).

Main Results:

• Citral exhibited antimicrobial activity against MRSA with MIC values ranging from 5-40 mg/mL and MBC values from 10-40 mg/mL.
• A sub-inhibitory dose of 2.5 mg/mL was identified.
• Citral demonstrated significant efficacy in inhibiting early-stage biofilm formation compared to mature biofilms.
• Modulation of virulence gene expression was observed, including underexpression of icaA and increased expression of icaD, seg, and sei in specific MRSA isolates.

Conclusions:

• Citral possesses significant antimicrobial and antibiofilm properties against MRSA.
• Citral can modulate the expression of key virulence factors in MRSA.
• Citral shows potential as an adjunct therapy to conventional antibiotics for managing MRSA infections.