>No, if it allows the organism to survive, it increases fitness by definition Wrong. Or rather, needlessly obtuse in the clear context under discussion. The fi

>No, if it allows the organism to survive, it increases fitness by definition Wrong. Or rather, needlessly obtuse in the clear context under discussion. The fitness function for human pathology is replication in excess of the body's capability to control/react adequately to maintain health. There's multiple counter factors going on. If an adapted resistant organism replicates 100x slower such that the immune system is then able to keep up and eliminate it, and/or the probalistic function drops below sustainment, then while yes it's successfully more fit vs the chemical compared to the vanilla organism from the perspective of patient health that's a huge win and the adapted organism has greatly reduced "fitness" (infectiousness/pathology) vs vanilla. The drug has done its job both destroying the vanilla and reducing danger of resistant, effectively driving evolution towards something more stable for humans. We don't need to avoid all organisms in our bodies, we merely need to avoid harmful ones that damage/destroy the host vs live with it to an acceptable degree (or even have mutual benefit). Some adaptions to some drugs don't have any effect on the pathology of the infectious agent, so they can resist it "for free" from a health perspective. If others mean the resistant is less dangerous than wild type that's good. I'm not really sure where the whole movie analogy stuff comes in.