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Antimicrobial susceptibility and time-kill analysis of single and combined essential oil blends against clinical and non-clinical isolates of bacteria and fungi

Adukwu, E.C; Edwards-Jones, V

Authors

Emmanuel Adukwu Emmanuel.Adukwu@uwe.ac.uk
Senior Lecturer in Placement Learning & Biological Science

V Edwards-Jones



Abstract

The continued emergence of antibiotic resistant bacteria and infection outbreaks in healthcare and community settings has created a need for development of new antibiotics and exploration of alternative therapeutics. Essential oils (EOs) have been identified as a potential alternative for use as antimicrobial agents. EOs are complex mixtures containing various chemical compounds with reports showing antimicrobial, antiviral, anti-inflammatory, and antifungal properties. In this study, EOs of geranium, manuka, lavender and lemongrass in single and combined blends were investigated for antimicrobial activity against a range of Gram positive bacteria, Gram negative bacteria and fungi. Methods: The agar incorporation and broth dilution assays were used in determining the MIC and MBC of the EOs. The time-kill assay was performed to compare the microbicidal activity of the single essential oils and a blend of two essential oils during several time intervals. The compositions of the single and combined EOs blends were characterized by GC-MS. The major components in the EOs were: citral (Lemongrass EO), citronellol and Citronellyl formate (Geranium EO), 3, 5-pyridinedicarbonitrile and 1s-cis-calamene (Manuka EO), Linalool and Linalyl acetate (Lavender EO). Results:The tested EOs demonstrated antimicrobial activity against the gram positive bacteria including the MRSA,Listeria monocytogenes and Enterococcus sp, as well as Candida sp. at concentrations between 4% (v/v) for manuka, geranium and lavender EOs. However, all the Gram negative bacteria were inhibited by Lemongrass EO at MIC concentrations 0.06 and 0.5%. Blending of Lemongrass EO with the other three EOs at a 1:1 ratio, caused a total inhibition of both gram positive and gram negative bacteria with MICs ranging between

Presentation Conference Type Poster
Start Date May 17, 2014
Peer Reviewed Not Peer Reviewed
APA6 Citation Adukwu, E., & Edwards-Jones, V. (2014, May). Antimicrobial susceptibility and time-kill analysis of single and combined essential oil blends against clinical and non-clinical isolates of bacteria and fungi. Poster presented at 114th General Meeting of the American Society for Microbiology Conference
Additional Information Title of Conference or Conference Proceedings : 114th General Meeting of the American Society for Microbiology Conference
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