MRSA stands for methicillin-resistant Staphylococcus aureus, a common type of bacteria that has become resistant to certain types of antibiotics. This type of bacteria is commonly found on the skin and in the noses of healthy people. In these places, the bacterium is usually harmless, but it can cause infection if it gets into the body through a cut or during surgery. When penicillin was first used, it was highly effective against Staphylococcus aureus infections, but most strains of the bacterium are now resistant to the antibiotic. Now, such staph infections are treated with methicillin and flucloxacillin, which must be given through an IV. However, some strains are resistant to these treatments, as well. MRSA rarely infects healthy people, and is most often seen in hospitals. The infection can develop in an open wound such as a bedsore or when there is a tube such as a urinary catheter that enters the body. People with long-term illnesses or who have compromised immune systems are at increased risk of infection. MRSA infections are treated with an antibiotic called vancomycin, which is derived from soil bacteria found in India and Indonesia. Vancomycin is extremely irritating to human tissue, so it is only used as a last resort. Still, some bacteria have become resistant even to this antibiotic, such as vancomycin-resistant Staphylococcus aureus (VRSA) and vancomycin-resistant enterococcus (VRE).