From what I've read, there are a few types of Staph (short for stapholococcus) bacteria. One type is farily common (about 30% of people have it on their skin), and fortunately, it isn't much of a problem. Then there's the Stapholococcus Aurealis (dunno if I've got the spelling right, but it's close), and there are two varieties of that (1) MRSA resistant and (2) non-MRSA resistant. If you have the MRSA resistant bacteria, well, you're SOL because that's the variety that is resistant to pennicilin and other anti-biotics.

Seems that bacteria have been becoming more and more resistant to the medicine we've used to fight them, and the pharmaceutical companies have been working on other drugs instead of new anti-biotics because the other drugs are much more profitable. So until they can charge big bucks for your next dose of pennicillin or whatever, we're all at the mercy of what those little buggers can do to us.

-Tock