A highly toxic mine pit may hold the answer to the growing threat of antibiotic-resistant bacteria. Researchers have found that when grown together, two species of fungi found in the tailing pond of a Montana mine produce a new compound that kills multiple strains of methicillin-resistant Staphylococcus aureus (MRSA).
Published in the Journal of Natural Products, the unexpected discovery was made after researchers from the University of Montana began isolating the compounds produced by microorganisms living in the Berkeley Pit Lake, a former open pit copper mine that is now heavily contaminated. While individually the fungi produced compounds that were of some interest to medicine, what happened when the two species were grown in conjunction with each other was surprising.
For the last few decades, researchers Andrea Stierle and Donald Stierle have been looking at what the fungi growing in the Berkeley Pit Lake have been producing. The lake, which is the result of an old copper mine that closed in 1983, has become incredibly acidic as the water washed over exposed oxidized rock. It now has a pH level of 2.5. Not only that, but heavy metals from the mining – such as arsenic and cadmium – have also leached into the lake.
This makes the water toxic to most life. Last year, for example, several thousand snow geese died after landing on the lake when they were trying to avoid a snow storm. Extremophiles, however, have managed to set up shop in the water, including different species of fungi.
Previous analysis has found that these microorganisms produce compounds that have the potential for medical use, for example being able to slow inflammation and even cell death. But it was when the researchers put together two separate species of Penicillium fungi that things got interesting. After extracting the proteins produced, they found one that looked like known antibiotics, spurring them to test it on bacteria.
They found that the molecules successfully killed four strains of MRSA. Often carried on the skin and in the nose and throat, MRSA has been a particular problem in hospitals, as it is resistant to the most widely used antibiotics and is opportunistic to those already ill.
The research goes to show that possible new antibiotics can be found in some of the most unexpected places. More research will be necessary to further test the compound and its medical possibilities.
1