The discovery of antibiotics was one of the most important findings of the 20th century. Antibacterial compounds have been used to treat human diseases caused by a variety of bacterial pathogens. However, due to evolution and natural selection, many bacterial pathogens have become resistant to the inhibitory actions of frequently used antibiotics. One example is Mycobacterium tuberculosis, the causative agent of tuberculosis. One solution to antibiotic resistance is the discovery of new antibiotics to replace those that have become ineffective. Because many antibiotics were originally isolated as compounds produced by microorganisms in order to eradicate other competing microorganisms, this project went back (to the microbial world) to focus on the previously uncharacterized soil bacteria which excrete compounds into the soil to inhibit growth of other competitive microbes.
One of our labís soil isolates, strain UD, has been shown using in vitro tests to inhibit growth of Mycobacterium smegmatis and M. phlei, two non-pathogenic surrogate test strains. In crude extracts of conditioned medium from UD cultures, the active anti-mycobacterial compound shows some properties of a stable polypeptide: resistance to heat treatment, susceptibility to certain proteases, and an apparent molecular weight in excess of 10 KDa. Further purification of the compound will allow determination of its effects on susceptible cells and its composition and structure.