In particular, Micrologix is targeting the improved compounds at drug-resistant bacteria such as Staphylococcus aureus and Mycobacterium tuberculosis. M. tuberculosis is the untreatable cause of tuberculosis, a disease that is presently re-emerging in many countries and kills approximately 3 million people each year. It is also worth mentioning the role of multidisciplinary research partnerships between researchers from different universities and other Networks of Centres of Excellence in developing of the initial Gramicidin S technology. Dr. Irvin, whose research also receives MRC funding, explains that bacterial resistance to antibiotics can take several forms. Many bacteria erect barriers in the cell wall to prevent conventional antibiotics from crossing it and reaching their internal target.
Some bacteria degrade or chemically modify the antibiotics that manage to cross the membrane.
Others may develop pumping systems to promptly expulse them, or mutate an antibiotic's intracellular target so that it won't be recognized. But Dr. Irvin says that because Gramicidin S works from the surface of a cell, these various resistance mechanisms have proven ineffective against it. Researchers are hopeful that no new ones will evolve. We would use them selectively, especially for bacteria that are more resistant to conventional antibiotics.