That's not really how antibiotic resistance develops: it happens at a population-level rather than an individual bacterium level. If, for example, you've got an

That's not really how antibiotic resistance develops: it happens at a population-level rather than an individual bacterium level. If, for example, you've got an antibiotic that messes with normal cell wall formation in a particular species, but some in the population randomly have some mutation that still allows the cell wall to function normally, those bacteria will survive the antibiotic. If the infection isn't then controlled by other means, the resistant bacteria will make up a larger percentage of the infecting bacterial population in the next generation. That's why taking full courses of antibiotics is important so that your immune system can focus on the resistant bacteria that the antibiotic can't touch.