February 13th, 2017
Ethnobotanist Cassandra Quave uncovered a medicinal mechanism in berries of the Brazilian peppertree(Credit: Ann Bordon/Emory University)
Superbugs are on the rise, with a UK government report last year warning that they could kill 10 million people a year by 2050. Scientists have unearthed what could be a valuable weapon on one of the key frontiers, discovering an extract from the Brazilian peppertree, an invasive weed found commonly across Florida, that can neutralize a dangerous antibiotic-resistant staph bacteria called Staphylococcus auereus.
Methicillin-resistant Staphylococcus auereus is a type of staph bacteria that has become resistant to many common antibiotics. Once mostly limited to nursing homes and hospitals, it has more recently spread to more common places like schools and gyms, where it can cause skin infections, bloodstream infections, sepsis and death.
The news isn't all bad on the MRSA front. The Centers for Disease Control and Prevention says that the percentage of Staphylococcus auereus resistant to the antibiotic methicillin has decreased significantly in recent years, as have the number of life-threatening MRSA infections in healthcare settings, resulting in 9,000 fewer deaths in hospital patients in 2011 than in 2005.
But still, there is work to be done, and we have seen researchers make some promising strides in the battle against MRSA. Biodegradable polymers, bacteria found in the honey stomach of bees and a sea sponge-derived compound that killed 98 percent of MRSA cells in testing have all shown great potential, and now scientists at Florida's Emory University have opened up another avenue of attack.
"Traditional healers in the Amazon have used the Brazilian peppertree for hundreds of years to treat infections of the skin and soft tissues," says Cassandra Quave, an assistant professor in Emory's School of Medicine's Department of Dermatology and co-author on the study. "We pulled apart the chemical ingredients of the berries and systematically tested them against disease-causing bacteria to uncover a medicinal mechanism of this plant."
Through their work, the team demonstrated that a compound taken from the berries slowed the formation of skin lesions in MRSA-infected mice. Rather than actually killing the MRSA bacteria, the compound interferes with a gene the cells use to communicate, work together and inflict damage.
"It essentially disarms the MRSA bacteria, preventing it from excreting the toxins it uses as weapons to damage tissues," Quave says. "The body's normal immune system then stands a better chance of healing a wound."
This holds some real advantages over the heavy-handed approaches sometimes used to attack superbugs, which involved blasting them with drugs that kill them off. And kill some of them off they might, but the stronger ones that do survive pass on their genes to offspring and add fuel to the spreading wildfire that is superbug evolution.
The researchers say the compound extracted from Brazilian peppertree, which is abundant across Florida and flourishes in subtropical climates, does no harm to the skin tissues of mice or the healthy bacteria found on the skin. They're now working to confirm the safest way to use the extract to battle superbugs, and are eyeing pre-clinical trials.
"If the pre-clinical trials are successful, we will apply for an application to pursue clinical trials, under the Food and Drug Administration's botanical drug pathway," says Quave.
The research is published in the journal Scientific Reports.