The discovery of penicillin in the early 1900s offered the possibility of a “magic bullet” for the treatment of bacterial infection. Bacteria have proven incredibly versatile, however, as new strains have evolved that can overcome the newest and most sophisticated antibiotics. Superbugs are strains of bacteria that are resistant to all available antibiotics. Staphylococcus aureus, also known as Staph, is a normally harmless skin-borne bacterium that can be lethal in patients with weakened immune systems. Strains of Staph function as superbugs that can tolerate all but the newest experimental drugs. As fast as new antibiotics are developed, Staph appears able to evolve resistance to them. Mark Wilke is researching the molecular mechanisms that regulate resistance to a class of antibiotics called beta-lactams. The findings could help explain how Staph bacteria switch their antibiotic resistance on and off, as well as lead to new strategies for combating Staph infections.