Bumblefoot will take a very strong one, if you use one at all. I quit using them because cleaning out the wound and packing with antibiotic ointment works just as well, unless it's gone systemic (that's very bad). Penicillin or other strong one would be what you want. At one time, someone suggested Cephalexin or Lincomycin, but honestly, I don't see much benefit in it if you clean out the wound and keep treating it topically. I've also used antibiotic ointment mixed with silver sulfadiazene cream and had success with that--that is usually for bad burns to prevent infection. I know a wildlife person who works with raptors and that is what they use for bumblefoot in their birds.