Genetic variability in a bacteria species

im guessing you all asume that penicilin was the first antibiotic that bacteria have ever encounterd to name a few natural antibioticsgarlic, honey, Carob powder, Aloe Vera, Grapefruit seed extract, ....all bacteria have had ample time in human history to develope a resistance to these natural antibiotics, that resistence could have helped them to evolve a resistance to industrial antibiotics.
in short they did not haveto invent a way to defend themselves from a totaly new substance they only hadto invent a way to defend themselves from a more powerful substance that kills them.

i know you just cant get them that pure in nature. so all bacteria could have had a small resistance to them already and they did not have to find the resistance only straighten it.