In a position trailing many countries in the developed world, the United States is taking steps to limit the routine use of antibiotics for cows, pigs and chickens. The Food and Drug Administration (FDA) announced that antibiotics will no longer be used to make animals grow bigger—and more profitable—but will be reserved to fight infections. A veterinarian must write a prescription for that.
Antibiotic-resistant infections kill many thousands every year worldwide. Microbial health is often decimated by antibiotic use.
This then is when stealthy pathogens such as Clostridium difficile take hold and weaken the host. Saccharomyces boulardii is a one probiotic that may offer some protection in such infections.
If antibiotic use wanes, good bacteria can flourish. For a full analysis on the subject, see this recent story in The New York Times.