> we will eventually understand the differences, which are biochemical differences at bottom, between human beings and bacteria, between human beings and protis

> we will eventually understand the differences, which are biochemical differences at bottom, between human beings and bacteria, between human beings and protists This is the stuff of the Nobel prizes of yore, and it is the mechanistic basis for how antibiotics kill bacteria and not humans. Penicillins destroy the cell wall as it is remodeled (humans don't have a cell wall); lincosamides block protein synthesis at the ribosome (humans have a different ribosomal structure); amphotericin binds ergosterol and forms ion channels in fungal membranes (humans lack ergosterol). As we continue to explore biochemistry, we will continue to understand (and perhaps even discover) new antimicrobials, though I suspect most of the future advances will come from large-scale screens of discovered or synthesized compounds without taking much biology into account until secondary stages (to increase potency or reduce toxicity).