Or did God (ahem - the designer) have to intervene mysteriously in order for the antibiotic resistance to develop?
How do you explain how antibiotic resistance arises in a population?
If a dictator gave order to shoot all the blonde people in his country, and a few generations later there were fewer blonde people around, would that be evolution?
Exactly. It changed. Just as humans "de-volved" the highly useful trait of malarial resistance through sickle cell anemia. The end result is degradation of higher life forms, hence the term "devolution".
"Or did God (ahem - the designer) have to intervene mysteriously in order for the antibiotic resistance to develop?"
Maybe He did. Maybe He didn't. Maybe the Bible is right: Maybe physical corruption of the creation is related to the moral corruption of creation.
How do you explain how antibiotic resistance arises in a population?
Resistance existed in some of the bacterial organisms, somewhere, somehow. Otherwise, by definition, they'd all be dead. The ones that didn't have resistance died. You can't "develop resistance" in dead organisms. Anyway, are "more destructive parasites" the definition of fitness?"
And this is all beside the point, because it still doesn't explain how you got a brain. Which is what Big E-volution is supposed to explain. You don't need that brain to propagate (your definition of "fitness"), you could have easily done it as a bacterium. And a lot more prolifically.