For the first time, a synthetic version of a non-psychoactive molecule found in marijuana has been shown to kill pathogenic bacteria that cause meningitis, gonorrhea, and legionnaires disease. Experts have been warning that microbial pathogens that resist many common antibiotics are becoming a serious threat to public health. This work may show that synthetic cannabidiol, which does not have an intoxicating effect, could be useful as a new kind of antimicrobial. The research, which demonstrated that synthetic CBD can kill bacteria including Neisseria gonorrhoeae, was reported in Communications Biology.
"This is the first time CBD has been shown to kill some types of Gram-negative bacteria. These bacteria have an extra outer membrane, an additional line of defense that makes it harder for antibiotics to penetrate," explained Associate Professor Mark Blaskovich of The University of Queensland Institute for Molecular Bioscience.
CBD was also found to work against a wider range of Gram-positive bacteria than was known, including antibiotic-resistant pathogens MRSA (methicillin-resistant Staphylococcus aureus).
Bacterial colonies often form tough biofilms that are far more resistant to desctruction than small colonies or individual microbes. These hardy biofilms can be difficult to eradicate, but Blaskovish noted that CBD is also able to break these down.
In this study, the researchers tested how CBD worked on bacteria, mimicking a two week treatment to see if the microbes would develop resistance to it.
"Cannabidiol showed a low tendency to cause resistance in bacteria even when we sped up potential development by increasing concentrations of the antibiotic during treatment," said Blaskovich. "We think that cannabidiol kills bacteria by bursting their outer cell membranes, but we don't know yet exactly how it does that and need to do further research.
The scientists also determined that chemicals that are very similar to CBD but have a slightly different structure, called analogs, were also able to kill the bacteria.
"This is particularly exciting because there have been no new molecular classes of antibiotics for Gram-negative infections discovered and approved since the 1960s, and we can now consider designing new analogs of CBD within improved properties."
"Congratulations to Dr. Blaskovich and his team for producing this significant body of research. The published data clearly establishes the potential of synthetic cannabinoids as antimicrobials," said study collaborator Vince Ippolito, the President and Executive Chairman of Botanix Pharmaceuticals Limited. "Our company is now primed to commercialize viable antimicrobial treatments which we hope will reach more patients in the near future. This is a major breakthrough that the world needs now."
Blaskovich added that the collaboration is rapidly leading to the creation of a topical form of CBD that could be tested in clinical trials this year.
"Now we have established that cannabidiol is effective against these Gram-negative bacteria, we are looking at its mode of action, improving its activity and finding other similar molecules to open up the way for a new class of antibiotics."