“Clays are little chemical drugstores in a packet,” said study co-leader Lynda Williams, a geochemist at Arizona State University in Tempe.
She and colleagues collected more than 20 different clay samples from around the world to find out which had the best antibacterial properties.
They say they were able to identify at least three that killed or significantly reduced the growth of infective agents like MRSA (methicillin-resistant Staphylococcus aureus), a bacterium that causes a flesh-eating disease known as Buruli ulcer, as well as E. coli and salmonella.
The team told the annual gathering of the American Chemical Society in New Orleans that they are working to identify which specific compounds in the clays are responsible for the antibacterial activity.
But the researchers caution that some mud can contain dangerous bacteria as well as toxic minerals like arsenic and mercury.
They say that until safe healing clays are developed and scientifically proven to work, which could take several years, hand washing and other proper hygiene techniques is the best way to keep MRSA and other harmful bacteria at bay.