Natural alternatives to fight MRSA

RESEARCH IT – Natural alternatives to fight MRSA and other resistant bacteria

Julien Thibault of IT Sligo, talks about a collaborative study conducted between the School of Science at the IT Sligo and the Department of Microbiology, Sligo General Hospital,which has found potential antibacterial agents from essential oils capable of killing a range of resistant bacteria including Methicillin-resistant Staphylococcus Aureus, better known as MRSA.  The results of this research were presented at the recent 10th Annual Research & Education Foundation, Sligo General Hospital, Multidisciplinary Research Conference.

Julien Thibault (PhD student) from IT Sligo and Karen Hickey, Senior Medical Scientist, Microbiology Department, SGH, began the study with funding from the Research and Education Foundation, SGH, to identify essential oils, and more particularly the constituents of these essential oils, which offer the highest efficacy and the broadest spectrum of activity against some of the most clinically significant resistant bacteria.  The resistant bacteria investigated were a range of MRSAs and also Vancomycin-resistant Enterococcus (VRE), Extended Spectrum Beta Lactamase (ESBL) producers and other multiresistant clinical isolates. These are often referred to as ‘Superbugs’ as they do not respond to, or are not treatable with a range of modern antibiotics.


Microscope image of coli bacteria

Hospitals now offer alcohol based hand wash dispensers at all entrance points to visitors in an effort to prevent the spread of infection.

In this research the goal was to examine the ability of essential oils and the constituents of these essential oils to kill some of these resistant bacteria. The work involved a wide range of microbiological testing which was carried out in the Microbiology Department of Sligo General Hospital.

Essential oils are available in a wide range of commercial outlets from pharmacies to health stores and supermarkets. Many people use them as antiseptic treatments and in aromatic oil burners. They are composed of plant extracts which generally contain a large number of chemicals, some of which have antibacterial properties. Much research has investigated the antibacterial nature of these essential oils, however, there has been little work carried out on their effect on these resistant bacteria.

The results of this research reveals that some of the oils tested and some of the individual constituents are highly efficient at killing the MRSA, VRE and ESBL strains tested. “We have tested a large range of oils and constituents and observed such activity with some of them, sometimes as low as 0.1% is required to kill 99.99% of the organisms in vitro!” comments Julien Thibault. Of these oils, Clove, Lemongrass, Citronella, Thyme, Oregano, Cinnamon or the popular Tea tree oil can be used quite effectively. Julien adds: “The list is not exhaustive, a large majority of the oils showed activity at relatively low concentrations”.

The study also identified and categorised constituents found in essential oils that are responsible for the oils activity: “The oils are complex mixtures of recurrent constituents where they may play a role on their own or in synergy, but from a pharmaceutical point of view it was important to start identifying which ones were the least and most potent”. Generally, the oils containing high amounts of the identified highly-active constituents are good antibacterial agents.


The lavender flower, rich source of essential oil

These initial results are promising in the fight against resistant organisms as they show unspecific broad-spectrum action against all isolates: “It is reassuring that not only are the essential oils’ constituents good antibacterial agents, they are also able to kill clinical isolates regardless of their resistance to conventional antibiotics. Further work is obviously needed to provide viable alternatives to patients: “This is a starting point, but we have to admit that natural products such as essential oils can be beneficial in the fight against resistant isolates”. Dr. Fiona McArdle, Sligo IT, supervisor on the project comments: “This study between the Institute and the Hospital is a good example of local collaboration. This study was initially funded by the Institutes of Technology, Strategic Innovation Fund and continued with the generous grant from the Research and Education Foundation, SGH, awarded in 2008. It is hoped that we will be able to further develop this research as there is huge potential in the use of natural products in the treatment and eradication of these resistant bacterial strains”.

For further information contact:

Julien Thibault


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