Antimicrobial Activity of Olea europaea Fatty Oil against Multi-Drug Resistant and Biofilm Forming Microorganisms

The aim of the present study was to investigate the potential antimicrobial activity of Olea europaea fatty oil against a collection of bacterial ( Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa ) and fungal ( Candida albicans ) clinical isolates. The antimicrobial and antibiofilm activity were evaluated by broth microdilution method for establishing the minimal inhibitory concentration (MIC) and microtiter assay for determining the minimal biofilm eradication concentration (MBEC). Some of the potential microbial targets of the fatty oil were investigated by flow cytometry (FCM). The results obtained hereby revealed that Olea europaea fatty oil inhibited microbial planktonic growth (MICs values of 5.23-41.8 mg/ mL) and biofilm development on inert substrata (MBEC values of 1.31-20.9 mg/ mL). The FCM measurements confirmed that the analyzed oil induced microbial membrane damages and inhibited microbial efflux pump activity.