Rumor has it that the antibiotics used for animals are the exact same thing as the people variety and don’t need a prescription.
(Found on survival threads. Ping to Kartographer)
How to Stockpile Antibiotics for Long Term Survival
http://www.freerepublic.com/focus/f-chat/2947506/posts
Antibiotics And Their Use in Collapse Medicine(tm), Part 1
http://www.freerepublic.com/focus/f-bloggers/2837144/posts