Not just animals
dcr100 wrote "Being vegan, I do my small part not to contribute to the problem. The side benefit is that I rarely get sick, and when I do, my body seems to make the illness rather mild."
But anitbiotics are used on plant life, too. Back in the late 1970s I bought a pound of streptomycin to treat an apple tree suffering from fireblight, a bacterial infection. I sprayed the entire tree regularly and held the disease at bay until I ran out of streptomycin.
I bought it at the local pharmacy for $6.00 for the pound, no prescription needed.
Are you ready to give up apples?