Researchers in Arizona have found that minerals from clay could provide a source of powerful antimicrobials for fighting deadly MRSA infections and other diseases.

Researchers said that unlike conventional antibiotics that are often administered by injection or pills, the so-called 'healing clays' could be used as rub-on creams or ointments to keep MRSA infections from spreading.

They said that clays also show promise against a wide range of other harmful bacteria, including those that cause skin infections and food poisoning.

"Clays are little chemical drug-stores in a packet. They contain literally hundreds of elements. Some of these compounds are beneficial but others aren't. Our goal is to find out what nature is doing and see if we can find a better way to kill harmful bacteria," said study co-leader Lynda Williams, Ph.D., a geochemist at Arizona State University in Tempe.

For the study, Willams and her colleagues collected more than 20 different clay samples from around the world to investigate their antibacterial activities.

The researchers tested each of the clays against several different bacteria known to cause human diseases.

These bacteria include MRSA (methicillin-resistant Staphylococcus aureus), Mycobacterium ulcerans (a microbe related to the tuberculosis bacterium that causes a flesh-eating disease known as Buruli ulcer), as well as E. coli and Salmonella (which cause food poisoning).

In collaboration with study co-leader Shelley Haydel, Ph.D., a microbiologist with Arizona State, the researchers identified at least three clays that killed or significantly reduced the growth of these bacteria.

Presently, the researchers are working to identify the specific compounds in the clays that may be responsible for its antibacterial activity.

With the help of electron and ion microscopy, the researchers are also exploring how these antibacterial clays interact with the cell membranes of the bacteria in order to find out how they kill.

The researchers are continuing their research to test new clay samples from around the world to determine their germ-fighting potential.

They hope that the more promising clays will be developed into a skin ointment or pill to fight a variety of bacterial infections or possibly as an agricultural wash to prevent food poisoning.

However, the researchers also pointed out that ordinary mud could contain dangerous bacteria as well as toxic minerals like arsenic and mercury.

They have suggested that until healing clays are developed that are scientifically proven, which could take several years, handwashing and other proper hygiene techniques may be the best way for keeping MRSA and other harmful bacteria at bay.

The findings were presented at the 235th national meeting of the American Chemical Society.