If you only got 1 infection, i wouldn't toss it. I'd say the chances are greater that you got an infection from bacteria on your skin. Alcohol swabs are only marginally more effective than nothing at all. To be safe, filter the gear and you'll be fine.
Keflex is a fantastic AB if it isn't MRSA. It is often the antibiotic of choice (or another related cephalosporin) for skin infections. I would avoid clinda if you can...it causes more C. Diff than any other antibiotic and that's really nasty. Better off going with Bactrim DS for MRSA. To be safe, you can always just use Bactrim as your first choice, as it's very broad spectrum and covers a wide variety of both gram neg and gram pos bacteria. It's a much safer choice in that regard than Keflex or Doxy...although it is a bit more toxic.
Also, general advice to everyone here--the second you suspect an infection, go to the ER. The IV dose of ABs will stop the infection in its tracks and can avoid surgical intervention. Time is of the essence.