oa Application Of Bioluminescence, Cyto And Genotoxicity To Measure The Efficacy Of Oregano Oil As An Antimicrobial Agent

Objectives To develop and validate a new technique for hand hygiene for use in healthcare settings; to evaluate correlation between bioluminescence and conventional time consuming viable counting methods; to use bioluminescent constructs of bacterial pathogens as a real time biosensors for rapid bactericidal monitoring and to conduct in vitro toxicity tests of the Himalayan oregano oil (HOO) against human cell lines. The ultimate aim of this study is to improve the quality of care of patients through application of a new hand hygiene which could be more acceptable to users while maintaining the efficacy of current hand hygiene disinfectant. Methods: Representatives of the common UK bacterial pathogens Escherichia coli, Pseudomonas aeruginosa and Methicillin sensitive Staphylococcus aureus were used in experiments. Strains used had been previously genetically modified with addition of lux CDABE operon to express bioluminescence in order that they could be used as reporter of viable metabolically active cells to show a real time in situ antimicrobial effect of HOO. Oregano oil samples were analysed for the percentage contents of thymol and carvacrol using gas chromatography. Potential toxicity of Oregano oil at a range of concentrations on cultured human keratinocytes and Jurkat cells were determined using Neutral Red, WST and MTS assays. Results: High correlation was obtained between viable count and bioluminescence. Application of HOO in concentrations effective against bacteria was found to be safe to human keratinocytes (fig.1 and 2) Conclusions: Bioluminescence has the capability to replace the plate culture method for evaluating the efficacy of a new antimicrobial product as it provides a rapid means of collecting data on the antimicrobial action of HOO. HOO may have the potential as a natural potent antimicrobial agent in the health care setting, as it has demonstrated biocidal action towards significant pathogens in a short time. Application of the oil in the correct dilution was found to be safe on human keratinocytes.