It's one of those cases where the good news is also the bad news. The hospital's lab identified the critters on my left leg as methicillin-resistant staphylococcus aureus, or MRSA.
The bad news is that this is one of those new 'resistant' strains of staph, that are fairly immune to old-school antibiotics.
The good news is that this isn't the 'good old days,' and MRSA and a particular sort of new antibiotic don't get along: at all.
I'm taking the 'correct' sort of antibiotic, and following other steps to deal with this infection.