They aren't, because pecillin is an antibiotic (which I have heard is weak,) and germs can "develop" resistance to it. Develop and evolve are actually the same thing for germs, bacteria, and viruses, they just evolve faster because they're smaller, and creatures don't evolve during their lifetime, their descendants have (slightly) different features that their parents didn't have, nor their grandparents, etc.
The Black Plague didn't come out of nowhere because of quick development, it was because of a genetic mutation (which is rare,) and caused the death of many people. Bacteria evolving has been observed hundreds of thousands of times. When scientists are searching for a cure for a disease, they aren't just looking for the disease's weakness, they're studying it's evolution and searching for factors of another disease. They are successful a large portion of the time with finding it. Changing half of the topic, When I see (extremely) religious people who have been given evidence of evolution, they just make a new word for it (like development of adaptation. Adaptation is existant but seperate) and they just shit on the argument and act like they won. You didn't really shit on it, you made a point, which changes my mind on things a bit, but, new name.
Neither of us are scientists, so we both are making some invalid points. I'm probably gonna stop making memes that point fingers at people.