Evaluation of Antibacterial and Antibiofilm Activity of Rice Husk Extract against Staphylococcus aureus

Area of Science:

• Microbiology
• Natural Product Chemistry
• Biotechnology

Background:

• Staphylococcus aureus infections are difficult to treat due to high antibiotic resistance.
• S. aureus biofilms reduce antibiotic efficacy and increase treatment challenges.
• Plant waste products offer a potential source for novel antimicrobial agents.

Purpose of the Study:

• To evaluate the antimicrobial and antibiofilm activity of rice husk extract (RHE) against Staphylococcus aureus.
• To assess the efficacy of RHE against both methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) S. aureus strains.
• To investigate the potential of RHE as a preventative agent against S. aureus biofilm formation.

Main Methods:

• Antimicrobial and antibiofilm assays were performed using clinical isolates of S. aureus.
• Confocal laser scanning microscopy with live/dead cell viability staining was used to analyze MRSA biofilms.
• Synergistic effects of RHE with antibiotics (oxacillin/cefoxitin) and toxicity in Galleria mellonella larvae were evaluated.

Main Results:

• High concentrations of RHE inhibited biofilm formation by both MRSA and MSSA isolates.
• RHE treatment reduced bacterial viability within MRSA biofilms.
• RHE demonstrated minimal ability to disaggregate pre-formed biofilms but showed an additive effect with antibiotics.

Conclusions:

• Rice husk extract possesses significant antimicrobial and antibiofilm properties against S. aureus.
• RHE effectively prevents S. aureus biofilm formation, with potential for use in topical solutions.
• The extract is non-toxic in vivo, supporting its potential application in medical devices to combat resistant bacterial infections.