SCIENTIFIC VALIDATION OF ANTIBACTERIAL MINERALS NEEDED FOR PUBLIC POLICY SUPPORT

The extensive use of antibiotics has led to an increase in antibiotic resistance in many pathogenic and clinically-relevant bacteria. Therefore, there is an ongoing need for identifying and analyzing new antimicrobials for existing antibiotic-resistant bacteria and for pathogenic bacteria for which there are no known effective therapeutic agents.

Recent documentation (www.burulibusters.com) revealed natural French clays that heal Buruli ulcer, a skin infection caused by Mycobacterium ulcerans. These observations drew our attention to the fact that these clays might reveal an antibiotic mechanism that could provide an inexpensive treatment for this otherwise incurable disease. Without scientific research and validation, the World Health Organization would not support the clay treatment for Buruli victims.

We have begun investigating the antibacterial properties of two of the French ‘healing' clays on a series of Gram-negative and Gram-positive pathogenic bacteria using standardized antimicrobial susceptibility experiments performed in triplicate. Initial bacterial cultures (~10⁷ bacteria/400 µl) were incubated with 200 mg of clay at 37°C on a rotating drum for 24 hours. After incubation, the bacteria – clay mixtures were diluted and plated onto agar to determine the number of viable bacteria.

Results show that one French clay exhibits an extraordinary ability to completely inhibit the growth of pathogenic E. coli, S. typhimurium, P. aeruginosa, and M. marinum and to partially inhibit the growth of pathogenic S. aureus. In contrast, the second clay, with similar bulk chemistry and mineralogical composition, shows enhanced E. coli and P. aeruginosa growth while S. typhimurium growth is unaffected.

Mineralogical and chemical testing shows differences between these two clays in trace elements, crystal size, and surface properties. Experiments that sequentially eliminate variables in the clay structure suggest that there is a chemical exchange that impedes an essential bacterial function. Our goal is to scientifically validate the observations that certain clays can heal bacterial infections and to determine the antibacterial mechanism.