I am a postdoctoral researcher at the ithree institute, specialising in the field of microbiology. My research focuses on understanding both the antimicrobial and prebiotic properties of honey, with a drive to use this knowledge to develop new treatments for infections caused by multi-drug resistant superbugs, and to use honey as a prebiotic to improve human gut health. I am equally passionate about doing research that has direct positive impacts for society, as I am about communicating my research to as broad an audience as possible.
My current research focuses on the antimicrobial properties of honey – understanding the mechanism of action by which honey kills pathogens without engendering resistance and profiling these 'active' honeys in Australia. I manage a multi-institutional, cross-disciplinary collaborative project funded by the Rural Industries Research & Development Corporation investigating the antibacterial activity of Australian Leptospermum (manuka-type) honeys.
I obtained my PhD from the University of NSW in 2015, where I studied the effects of various honeys on the growth of the beneficial and potentially harmful microbes in the human gut. I was one of the first researchers to show a positive impact on the beneficial gut populations and my initial results led to further research in the form of a human clinical trial, where I investigated the impacts of eating honey on gut health. My research contributed to the development of a world-first prebiotic honey product registered as a therapeutic agent in Australia.
My interest in the medicinal and health benefits of honey started during my Bachelor of Science (Molecular Biotechnology) degree at the University of Sydney in 2007, where I completed an Honours project investigating the antibacterial effect of honey on problematic human pathogens. I showed for the first time that resistance to the killing effects of honey could not be generated.
Member of the Australian Society for Microbiology
Can supervise: YES
Liu, M.Y., Cokcetin, N.N., Lu, J., Turnbull, L., Carter, D.A., Whitchurch, C.B. & Harry, E.J. 2017, 'Rifampicin-Manuka Honey Combinations Are Superior to Other Antibiotic-Manuka Honey Combinations in Eradicating Staphylococcus aureus Biofilms.', Frontiers in microbiology, vol. 8, p. 2653.View/Download from: UTS OPUS or Publisher's site
Chronic wound infections are a major burden to both society and the health care industry. Bacterial biofilms are the major cause of chronic wound infections and are notoriously recalcitrant to treatments with antibiotics, making them difficult to eradicate. Thus, new approaches are required to combat biofilms in chronic wounds. One possible approach is to use drug combination therapies. Manuka honey has potent broad-spectrum antibacterial activity and has previously shown synergistic activity in combination with antibiotics against common wound pathogens, including Staphylococcus aureus. In addition, manuka honey exhibits anti-biofilm activity, thereby warranting the investigation of its potential as a combination therapy with antibiotics for the topical treatment of biofilm-related infections. Here we report the first use of MacSynergy II to investigate the response of established S. aureus (strain NCTC 8325) biofilms to treatment by combinations of Medihoney (medical grade manuka honey) and conventional antibiotics that are used for preventing or treating infections: rifampicin, oxacillin, fusidic acid, clindamycin, and gentamicin. Using checkerboard microdilution assays, viability assays and MacSynergy II analysis we show that the Medihoney-rifampicin combination was more effective than combinations using the other antibiotics against established staphylococcal biofilms. Medihoney and rifampicin were strongly synergistic in their ability to reduce both biofilm biomass and the viability of embedded S. aureus cells at a level that is likely to be significant in vivo. Other combinations of Medihoney and antibiotic produced an interesting array of effects: Medihoney-fusidic acid treatment showed minor synergistic activity, and Medihoney-clindamycin, -gentamicin, and -oxacillin combinations showed overall antagonistic effects when the honey was used at sub-inhibitory concentration, due to enhanced biofilm formation at these concentrations which could not be counter...
Cokcetin, N.N., Pappalardo, M., Campbell, L.T., Brooks, P., Carter, D.A., Blair, S.E. & Harry, E.J. 2016, 'The Antibacterial Activity of Australian Leptospermum Honey Correlates with Methylglyoxal Levels.', PloS one, vol. 11, no. 12, p. e0167780.View/Download from: UTS OPUS or Publisher's site
Most commercially available therapeutic honey is derived from flowering Leptospermum scoparium (manuka) plants from New Zealand. Australia has more than 80 Leptospermum species, and limited research to date has found at least some produce honey with high non-peroxide antibacterial activity (NPA) similar to New Zealand manuka, suggesting Australia may have a ready supply of medical-grade honey. The activity of manuka honey is largely due to the presence of methylglyoxal (MGO), which is produced non-enzymatically from dihydroxyacetone (DHA) present in manuka nectar. The aims of the current study were to chemically quantify the compounds contributing to antibacterial activity in a collection of Australian Leptospermum honeys, to assess the relationship between MGO and NPA in these samples, and to determine whether NPA changes during honey storage. Eighty different Leptospermum honey samples were analysed, and therapeutically useful NPA was seen in samples derived from species including L. liversidgei and L. polygalifolium. Exceptionally high levels of up to 1100 mg/kg MGO were present in L. polygalifolium honey samples sourced from the Northern Rivers region in NSW and Byfield, QLD, with considerable diversity among samples. There was a strong positive relationship between NPA and MGO concentration, and DHA was present in all of the active honey samples, indicating a potential for ongoing conversion to MGO. NPA was stable, with most samples showing little change following seven years of storage in the dark at 4°C. This study demonstrates the potential for Australian Leptospermum honey as a wound care product, and argues for an extension of this analysis to other Leptospermum species.
Carter, D.A., Blair, S.E., Cokcetin, N.N., Bouzo, D., Brooks, P., Schothauer, R. & Harry, E.J. 2016, 'Therapeutic Manuka Honey: No Longer So Alternative.', Frontiers in microbiology, vol. 7, p. 569.View/Download from: UTS OPUS or Publisher's site
Medicinal honey research is undergoing a substantial renaissance. From a folklore remedy largely dismissed by mainstream medicine as "alternative", we now see increased interest by scientists, clinical practitioners and the general public in the therapeutic uses of honey. There are a number of drivers of this interest: first, the rise in antibiotic resistance by many bacterial pathogens has prompted interest in developing and using novel antibacterials; second, an increasing number of reliable studies and case reports have demonstrated that certain honeys are very effective wound treatments; third, therapeutic honey commands a premium price, and the honey industry is actively promoting studies that will allow it to capitalize on this; and finally, the very complex and rather unpredictable nature of honey provides an attractive challenge for laboratory scientists. In this paper we review manuka honey research, from observational studies on its antimicrobial effects through to current experimental and mechanistic work that aims to take honey into mainstream medicine. We outline current gaps and remaining controversies in our knowledge of how honey acts, and suggest new studies that could make honey a no longer "alternative" alternative.
Blair, S., Cokcetin, N., Harry, L. & Carter, D. 2009, 'The unusual antibacterial activity of medical-grade Leptospermum honey: antibacterial spectrum, resistance and transcriptome analysis', European Journal of Clinical Microbiology & Infecti..., vol. 28, no. 10, pp. 1199-1208.View/Download from: UTS OPUS or Publisher's site
There is an urgent need for new, effective agents in topical wound care, and selected honeys show potential in this regard. Using a medical-grade honey, eight species of problematic wound pathogens, including those with high levels of innate or acquired antibiotic resistance, were killed by 4.0-14.8% honey, which is a concentration that can be maintained in the wound environment. Resistance to honey could not be induced under conditions that rapidly induced resistance to antibiotics. Escherichia coli macroarrays were used to determine the response of bacterial cells to a sub-lethal dose of honey. The pattern of gene expression differed to that reported for other antimicrobial agents, indicating that honey acts in a unique and multifactorial way; 78 (2%) genes were upregulated and 46 (1%) genes were downregulated more than two-fold upon exposure to the medical-grade honey. Most of the upregulated genes clustered into distinct functional regulatory groups, with many involved in stress responses, and the majority of downregulated genes encoded for products involved in protein synthesis. Taken together, these data indicate that honey is an effective topical antimicrobial agent that could help reduce some of the current pressures that are promoting antibiotic resistance.