It's hard to imagine a world without antibiotics, but because of widespread overuse of the drugs, that's where we're headed. The Centers for Disease Control and Prevention says that in the U.S. alone, more than 23,000 people now die every year from infections that antibiotics can no longer cure. A study commissioned by the U.K. government estimated that by 2050, antibiotic resistance will cause 10 million deaths worldwide annually. Scientists have struggled to develop new drugs that can kill these superbugs. Consider the major class of antibiotics called macrolides, which treat common bacterial infections, including pneumonia, strep throat, ear and skin infections, and sexually transmitted diseases.