What is MRSA?

Here's a Wikipedia description on what MRSA is:

Methicillin-resistant Staphylococcus aureus (MRSA) is a specific strain of the Staphylococcus aureus bacterium that has developed antibiotic resistance to all penicillins, including methicillin and other narrow-spectrum β-lactamase-resistant penicillin antibiotics. MRSA was first discovered in the UK in 1961 and is now widespread, particularly in the hospital setting where it is commonly termed a superbug.
MRSA may also be known as oxacillin-resistant Staphylococcus aureus (ORSA) and multiple-resistant Staphylococcus aureus, while non-methicillin resistant strains of S. aureus are sometimes called methicillin-susceptible Staphylococcus aureus (MSSA) if an explicit distinction must be made.

http://en.wikipedia.org/wiki/MRSA