Source: Thailand Medical News Jan 20, 2020 4 years, 10 months, 1 day, 5 hours, 19 minutes ago
An
antibiotic compound made by
cannabis plants has been found to wipe out
drug-resistant bacteria, raising hopes of a new weapon in the fight against
superbugs.
Medical scientists screened and tested five cannabis compounds for their antibiotic properties and found that one,
cannabigerol (
CBG), was particularly potent at killing
methicillin-resistant Staphylococcus aureus (
MRSA), one of the most common hospital
superbugs.
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Lab tests showed that
CBG, which is not psychoactive, killed common
MRSA microbes and “persister” cells that are especially resistant to
antibiotics and that often drive repeat infections. The compound also cleared up hard-to-shift “biofilms” of
MRSA that can form on the skin and on medical implants.
Having observed how effective the substance was against
bacteria in the lab, the researchers decided to test
CBG’s ability to treat infections in animals. In a study that has not yet been published, they found that
CBG cured mice of
MRSA infections as effectively as vancomycin, a drug widely considered to be the last line of defence against
drug-resistant microbes. The study is under review at the ACS Infectious Diseases journal.
Dr Eric Brown, a microbiologist who led the work at McMaster University in Hamilton, Ontario, told
Thailand Medical News, “
Cannabinoids were clearly great drug-like compounds but noted it was early days in assessing the compounds for use in the clinic. There is much work to do to explore the potential of the
cannabinoids as
antibiotics from the safety standpoint.”
These days,
antibiotic resistance has become a major threat to public health. Britain’s former chief medical officer Dame Sally Davies has said the loss of effective
antibiotics would lead to “apocalyptic scenarios”, with patients dying from routine infections and many operations becoming too risky to perform.
The researchers describe how the rapid global spread of
drug resistance, caused by microbes developing mutations that protect them against
antibiotics, has driven an urgent need to explore new sources of drugs. Among
antibiotics in use today, the newest date back to discoveries made more than 30 years ago.
Typically,
bacteria fall into two classes depending on the makeup of their cells.
MRSA bugs are known as gram positive
bacteria, and have a single, thick cell membrane. Gram negative bugs differ in hav
ing inner and outer cell membranes, and these infections can be harder to treat. In the World Health Organization’s priority list of
drug-resistant bacteria, all three ranked as a “critical” priority are gram negative, namely
Acinetobacter baumannii,
Pseudomonas aeruginosa and
Enterobacteriaceae.
Dr Brown found that
CBG and other
cannabinoids did not work well against gram negative multi-
drug resistant bugs. But the team went on to show that when
CBG was used with small quantities of polymyxin B, an existing
antibiotic that disrupts the outer membrane of gram negative
bacteria, the
cannabis compound wiped out the
drug-resistant pathogens.
Though
Cannabis plants are thought to make the compounds to fight off invading pathogens there are other ways to produce
CBG. To study the compound, Dr Brown’s team synthesised it in the lab using the chemicals olivetol and geraniol. “We are now pursuing the required paperwork to work with a wide variety of
cannabinoids,” he said.
Dr Mark Blaskovich, who studies
antibiotic cannabis compounds at the University of Queensland, said
cannabis seemed to be particularly rich in
antibiotics, though other plants such as tea tree, garlic and the spices turmeric and curcurmin also contained antibacterials.
Dr Blaskovich added, “These are likely made as a defence mechanism to protect the plant from bacterial and fungal infections, but to date have not been very useful for human infections as they really only work outside the body. That’s what makes this new report potentially exciting evidence that
cannabigerol is able to treat a systemic infection in mice.”
Reference: Uncovering the hidden antibiotic potential of Cannabis
Maya A. Farha, View ORCID ProfileOmar M. El-Halfawy, Robert T. Gale, Craig R. MacNair, Lindsey A. Carfrae, Xiong Zhang, Nicholas G. Jentsch, Jakob Magolan, Eric D. Brown, doi: https://doi.org/10.1101/833392
