Dear EarthTalk: How is it that antibiotics are being “overused,” as I’ve read, and what are the potential consequences? —Mitchell Chase, Hartford, CT

The development and widespread adoption of so-called “antibiotics”—drugs that kill bacteria and thereby reduce infection—has helped billions of people live longer, healthier lives. But all this tinkering with nature hasn’t come without a cost. The more we rely on antibiotics, the more bacteria develop resistance to them, which makes treating infections that much more challenging.

According to the U.S. Centers for Disease Control and Prevention (CDC), overuse of antibiotics by humans—such as for the mistreatment of viral infections—means these important drugs are less effective for all of us. Besides the toll on our health, researchers estimate that antibiotic resistance causes Americans upwards of $20 billion in additional healthcare costs every year stemming from the treatment of otherwise preventable infections.

A bigger issue, though, is our growing …