Picture the last time a small cut on your hand turned red and angry. Most of us shrug it off, slap on an ointment, and move on. That easy confidence rests on a quiet assumption, that antibiotics will keep working. They aren’t, not all of them, and the cracks are showing in one of the most common bugs around, Staphylococcus aureus. Two forms of it scare doctors most. MRSA shrugs off methicillin and most other beta-lactams. QRSA shrugs off quinolones. When a strain resists both, the menu gets short fast. A team working on naphthoquinone chemistry thinks they may have found a different way in. I read the study, and…