Staphylococcus aureus is the name of the invisible enemy in hospitals. The bacterium is actually harmless. It settles on the skin and in the upper airways, where it clusters together like tiny bunches of grapes. Nearly 30 percent of all people in Germany carry the pathogen, and the figure is even higher for nurses and doctors, at about 90 percent. In most cases, S. aureus does not cause any symptoms of disease, but if the host’s immune system is weakened, it attacks the skin, muscles, or airways. That in itself should also be harmless since the discovery of antibiotics. But strains that are resistant to common classes of antibiotics, such as quinolones and tetracyclines, aminoglycosides and sulfonamides, are being found increasingly often in hospital settings. Now, houseflies and honeybees, butterflies and mealworm beetles could help find new methods in the fight against antibiotic-resistant bacteria.