“You mean, for example, the fact that granulocytes have antibiotics in them, as does saliva?”
I’m talking specifically about the fungi that Fleming found the antibiotic in.
Remember, he found that a contamination with a mold caused the bacteria he was studying to not grow. It was because the mould produced penicillin.
Certain micro organisms naturally produce chemical anti-biotics as a defense and certain bacteria may have a defense against it.
My point is antibiotics are ubiquitous in nature, this is widely known since Fleming, and it’s irrelevant.