A mighty weed versus a drug-resistant superbug

The red berries of a weed found in the southern United States contain an compound that can disarm a deadly superbug, according to research published Friday.

Researchers from the University of Iowa and Emory University 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.

Cassandra Quave, an Emory University scientist who studies how indigenous people use plants in healing practices, said researchers pulled apart the chemical ingredients of the berries and tested them in mice infected with these 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 shrunk.

Instead of destroying the bacteria, the ingredients in the fruit weakened the bacteria by preventing them from producing the toxins it uses as weapons to damage tissue. The extracts from the fruit repress a gene that allows the bacterial cells to communicate with one another.

'It weakens the bacteria so the mouse's own defenses work better” to clear the infection, she said. 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 fall.

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 United States, according to federal statistics.