I’ve written often (here and here, just for starters) how we have not developed new methods to eradicate infections from our bodies. We use microbes to fatten our animals- cattle, chicken, etc.- because we’ve learned that putting antibiotics in animal feed not only keeps many infections at bay- even if they are not ready to invade the livestock- but feeding the antibiotics makes the animals gain weight- fast. Which cuts the amount of time farmers and ranchers need to maintain the animals before they are slaughtered for our food.