Substance derived from the cannabis plant can combat MRSA

In new results, scientists from Roskilde University have shown that individual chemical components of cannabis have an effective impact on methicillin-resistant Staphylococcus aureus (MRSA). The results confirm existing research and add crucial new knowledge on how active molecules from the cannabis plant can be applied in combination with a number of traditional antibiotics currently used to treat MRSA in humans. The results could lay the groundwork for the development of new types of medicine that could reduce consumption of conventional antibiotics and curb the growth of antibiotic resistance.
Picture of scientist using HPLC equipment to separate CBD from other cannabis molecules.
In the laboratories at Roskilde University, scientists use HPLC equipment to separate CBD from other cannabis molecules. Photo: Kasper Hornbæk.


As the incidence of antibiotic resistance grows, so does the interest in a combined treatment using several different types of medication which could reduce the total consumption of antibiotics. The fundamental challenge to public health is that more and more bacteria are developing resistance to known antibiotics. There is therefore an urgent need to identify new antimicrobial substances that can be used as an alternative to antibiotics in the fight against multi-resistant bacteria.

In new research from Roskilde University, scientists Håvard Jenssen, Torben Lund, Laura Daniela Martinenghi and Rie Jønsson have investigated whether selected chemical compounds from cannabis have an effective impact on methicillin-resistant Staphylococcus aureus (MRSA). Earlier this year, similar experiments performed at the University of Southern Denmark and elsewhere showed positive results, and the research from Roskilde University has supplemented this with new knowledge about the bactericidal effect of molecules from the cannabis plant in combination with seven known antibiotics. 

In the new experiments, the four researchers, using a relatively simple heat treatment, converted the naturally occurring substance cannabidiolic acid in the cannabis plant into cannabidiol (CBD). They then studied the effect of CBD. 

The results of the research show that CBD has in itself a strong antimicrobial effect on MRSA, and that a potential therefore exists to develop CBD-based medications that could be used as an alternative to traditional antibiotics in the treatment of MRSA. 

New combination treatments

The experimental results support the results of other research, and represent the most systematic test to date of the antimicrobial effect of CBD on a broad spectrum of relevant bacteria. 

For the first time, the results document a positive effect from the combination of CBD with seven classic antibiotics currently used to treat humans, including the drug Vancomycin, which is used to treat particularly complicated infections and is therefore often the last resort of doctors in their treatment of MRSA. 

The results from Roskilde University thereby show that when fighting MRSA with both CBD and a conventional antibiotic, it is possible to achieve a so-called additive effect of the two drugs. Specifically, this means that a dose of one drug can be replaced by a dose of the other without the treatment losing its overall effect, i.e. that bacteria can be effectively combatted even using significantly smaller doses of traditional antibiotics. 

The great potential of the results is thus that using a combination treatment of CBD with conventional antibiotics, it will be possible to reduce the doses of conventional antibiotics with which humans must be treated in order to achieve an effect. The combination treatment thereby also has the potential to curb the development of antibiotic resistance in humans. 

Challenges scepticism towards medicinal cannabis

The use of medicinal cannabis has often been met with opposition from politicians, the general public and parts of the health service, who are sceptical of the effect. The new results from the scientists at the Department of Science and Environment are a contribution to establishing a more factual basis for the debate. 

“The new research results, like those of previous experiments, document the effect of CBD and may thereby help to legitimise treatment with preparations based on individual chemical components of medicinal cannabis,” says Håvard Jenssen. 
 

More information:

Learn more about the findings in the full scientific publication (open access).

 

Contact: 

Professor (MSO) Håvard Jenssen, e-mail: jenssen@ruc.dk, phone: +45 46 74 28 77.