Cannabinoid shows promise as antibiotic for MRSA

One of hundreds of cannabinoids, cannabichromenic acid (CBCA) may hold an important key to combatting methicillin-resistant Staphylococcus aureus (MRSA), the superbug that kills at least 9,000 people in the US each year and has left healthcare providers scrambling for solutions.

It is believed half of all hospital-acquired infections are due to MRSA, a problem that is exacerbated by the lack of development of new antibiotics.

Now, a group of Australian researchers has shown CBCA possesses stronger antibiotic activity against MRSA than vancomycin, currently one of the few frontline treatments for infections with this superbug.

Given that most of the antibiotics currently used, including beta-lactams and tetracyclines, were found by this type of bioprospecting (i.e., the search and discovery of compounds that exist in plants), it makes sense to look at cannabinoids. Previous studies have already shown antibiotic activity for CBD, THC, and CBG (cannabigerol).

In the present study, the authors found CBCA inhibited the growth of MRSA and other pathogenic bacteria that cause infectious diseases. While antibiotics like vancomycin often fail to work against higher densities of bacteria—like those seen in patients—CBCA’s antibacterial activity outperformed vancomycin in those situations.

The inhibitory effect of CBCA persisted even once cell growth and division had ceased, which was also not the case for vancomycin. Additionally, the concentrations of CBCA they used were well below the levels at which it was toxic to the mammalian cells tested.

This is hopeful news—given the rise of antibiotic-resistant strains of bacteria and fungi they were meant to treat and the constant battle science has waged against infectious microbes—but further research will be required to assess the efficacy of CBCA to supplement our arsenal of weapons against superbugs like MRSA.