Researchers from the University of Queensland, in collaboration with Botanix Pharmaceuticals Limited, have found that cannabidiol (CBD), a nonpsychoactive compound in cannabis, can kill drug-resistant bacteria, including those behind infections like gonorrhea, meningitis and legionnaires disease.
"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 defence that makes it harder for antibiotics to penetrate," says Dr Mark Blaskovich, one of the study's authors.
To test the compound's antibiotic abilities, the researchers mimicked a two-week patient treatment in lab models. From these models, they found that CBD is particularly good at breaking down biofilms (slimy buildups of bacteria) that increase their chances of survival against existing antibiotic treatments.
The researchers also found that CBD showed a low tendency to cause drug resistance in bacteria. This remained true even when they sped up potential drug resistance by increasing concentrations of CBD during the treatment phase.
While the researchers suspect that CBD kills bacteria by bursting their outer cell membranes, they say that further research is needed to confirm the mechanism of action. In the meantime, they also found that synthetically made chemical analogs of CBD worked with similar efficacy in killing 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." say the researchers.
The researchers now plan to conduct further research into the mode of action of cannabis as an antibiotic, ways to improve its efficacy, and molecules with similar effects. In the meantime, they are waiting for Phase 2a trials to begin early this year for a topical CBD formulation capable of decolonizing MRSA before surgery. This, they hope, will pave the way for further treatments for conditions including gonorrhea, meningitis, and legionnaires disease.