Eugenol: A Phyto-Compound Effective against Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Clinical Strain Biofilms

Abstract

BackgroundInhibition and eradication of Staphylococcus aureus biofilms with conventional antibiotic is difficult, and the treatment is further complicated by the rise of antibiotic resistance among staphylococci. Consequently, there is a need for novel antimicrobials that can treat biofilm-related infections and decrease antibiotics burden. Natural compounds such as eugenol with anti-microbial properties are attractive agents that could reduce the use of conventional antibiotics. In this study we evaluated the effect of eugenol on MRSA and MSSA biofilms in vitro and bacterial colonization in vivo.Methods and ResultsEffect of eugenol on in vitro biofilm and in vivo colonization were studied using microtiter plate assay and otitis media-rat model respectively. The architecture of in vitro biofilms and in vivo colonization of bacteria was viewed with SEM. Real-time RT-PCR was used to study gene expression. Check board method was used to study the synergistic effects of eugenol and carvacrol on established biofilms. Eugenol significantly inhibited biofilms growth of MRSA and MSSA in vitro in a concentration-dependent manner. Eugenol at MIC or 2×MIC effectively eradicated the pre-established biofilms of MRSA and MSSA clinical strains. In vivo, sub-MIC of eugenol significantly decreased 88% S. aureus colonization in rat middle ear. Eugenol was observed to damage the cell-membrane and cause a leakage of the cell contents. At sub-inhibitory concentration, it decreases the expression of biofilm-and enterotoxin-related genes. Eugenol showed a synergistic effect with carvacrol on the eradication of pre-established biofilms.Conclusion/Major FindingThis study demonstrated that eugenol exhibits notable activity against MRSA and MSSA clinical strains biofilms. Eugenol inhibited biofilm formation, disrupted the cell-to-cell connections, detached the existing biofilms, and killed the bacteria in biofilms of both MRSA and MSSA with equal effectiveness. Therefore, eugenol may be used to control or eradicate S. aureus biofilm-related infections.

Pterostilbene Enhanced Anti-Methicillin Resistant <i>Staphylococcus aureus</i> (MRSA) Activity of Oxacillin

“…This is in line with Kyaw and Lim (2012) which reported that eugenol which is a bacteriostatic phytochemical (Rastogi et al, 2008;Yadav et al, 2015) in combination with a bacteriostatic antibiotic minocycline produced indifference interaction. According to Qin et al (2013), indifference is when the combined action is the same as with either component alone.…”

Eugenol inhibits quorum sensing and biofilm of toxigenic MRSA strains isolated from food handlers employed in Saudi Arabia

“…Therefore, it is envisaged that eugenol is effective against ica-independent biofilm formation. Similar findings were reported with eugenol in inhibition of biofilms of MRSA strains of clinical origin [14,38].…”

“…It is also important industrially and has been used as a flavouring agent in food and cosmetic products [13]. Recently, biofilm inhibition and eradication properties of eugenol against MRSA and methicillin-sensitive S. aureus (MSSA) clinical strains have been reported [14]. However, the effect of eugenol on QS and biofilm of MRSA strains isolated from food handler's is not studied yet.…”

Versatile and Synergistic Potential of Eugenol: A Review

“…At sub-MIC eugenol significantly decreased 88% S. aureus colonization in rat middle ear. MBEC (minimum biofilm eliminating concentration) of eugenol and carvacrol combination decreased the already formed biofilms by 99% [30]. Eugenol at 0.5 MIC was able to induce an inhibition of ≥ 90% of P. aeruginosa biofilms [31].…”