Grapefruit seed extract might be used as an anti-biofilm agent that is effective against S. aureus and E. coli. - GreenMedInfo Summary

Grapefruit seed extract (GSE) is a safe and effective preservative that is used widely in the food industry. However, there are few studies addressing the anti-biofilm effect of GSE. In this study, the anti-biofilm effect of GSE was investigated against biofilm-forming strains ofand. The GSE minimum inhibitory concentration (MIC) forandwere 25μg/ml and 250 μg/ml, respectively. To investigate biofilm inhibition and degradation effect, crystal violet assay and stainless-steel were used. Biofilm formation rates of four strains (7, and8,ATCC 25922, andO157:H4 FRIK 125) were 55.8%, 70.2%, 55.4%, and 20.6% at 1/2× MIC of GSE, respectively. The degradation effect of GSE on biofilms attached to stainless-steel coupons was observed (≥1 log CFU/coupon) after exposure to concentrations above the MIC for all strains and 1/2 × MIC for7. In addition, the specific mechanisms of this anti-biofilm effect were investigated by evaluating hydrophobicity, auto-aggregation, exopolysaccharide (EPS) production rate, and motility. Significant changes in EPS production rate and motility were observed in bothandin the presence of GSE, while changes in hydrophobicity were observed only in. No relationship was seen between auto-aggregation and biofilm formation. Therefore, our results suggest that GSE might be used as an anti-biofilm agent that is effective againstand.