Common weed thwarts deadly superbug
The red berries of a weed found in the southern United States contain a compound that can disarm a deadly superbug, according to new research.
Researchers from Emory University and the University of Iowa found that extracts from the Brazilian peppertree, which traditional healers in the Amazon have used for hundreds of years to treat skin and soft tissue infections, have the power to stop methicillin-resistant Staphylococcus aureus (MRSA) infections in mice.
The study was published in Nature’s Scientific Reports yesterday.
Cassandra Quave, an Emory scientist who studies how indigenous people use plants in healing practices, said researchers pulled apart the chemical ingredients of the berries and tested them on mice infected with superbug strains.
The mice developed skin lesions where the bacteria were injected. The researchers then injected some mice with the pepper extracts, and their lesions shrank.
Instead of destroying the bacteria, the ingredients in the fruit weakened the bacteria by preventing them from producing the toxins they use as weapons to damage tissue. The extracts from the fruit repress a gene that allows the bacterial cells to communicate with one another.
The plant extracts prevented the formation of skin lesions in mice injected with MRSA, but didn’t harm the skin tissues or the normal, healthy bacteria found on skin.
The discovery may hold the potential for new ways to treat and prevent antimicrobial-resistant infections, an enormous global problem that was the focus of a rare high-level United Nations summit last year.
MRSA has become a serious threat to human health. In 2011, it was responsible for more than 80,000 invasive infections and more than 11,000 deaths in the US, according to federal statistics.
Antimicrobial resistance refers to infections that have evolved the ability to withstand drugs that ought to stop them. The medicines include antibiotics, which act on bacteria, as well as drugs to fight fungal, viral or parasitic infections. Fighting bacteria with drugs designed to kill them helps to fuel the problem of antibiotic resistance if stronger bacteria can survive and evolve to become ‘‘superbugs’’.
The Brazilian peppertree, a shrubby tree native to South America, is an invasive species throughout the southern US, particularly in Florida, where it is considered a noxious weed. The plant has long been a staple in Brazilian traditional medicine. Its leaves and bark are used to treat wounds, ulcers, burns and skin infections.
Less is known about the plant’s fruit, which was used traditionally to make poultices for infected wounds and ulcers.