Staphylococcus aureus belongs to the Staphylococcus family. The bacteria are round and tend to cluster. It is found in humans as part of their normal flora on skin, in the nares, in animals and the environment. Staph. aureus was first discovered in 1881. Healthcare personnel and patients are frequently colonized with the bacteria. Transmission mode is direct- and indirect contact but also true airborne transmission. Staph.aureus can cause skin and wound infections, urinary tract infections, sepsis, meningitis and food poisoning. Although treatment with antibiotics is available, Staph.aureus showed signs early resistance towards antibiotics already in the beginning of 1960s. Today some Staph.aureus strains are multi resistant (MRSA) and this is an increasing problem world wide.