It"s difficult to imagine a world without antibiotics. They cure diseases that killed our ancestors in crowds, and enable any number of medical procedures and treatments that we now take for granted. Yet in 1945, while accepting a Nobel Prize for【C1】______penicillin, Alexander Fleming【C2】______a future in which antibiotics had been used with【C3】______and bacteria had grown resistant to them. Today, this future is approaching. Speaking to reporters last fall, Tom Frieden, the director of the Centers for Disease Control and Prevention,【C4】______a similar alarm: "If we"re not【C5】______, we will soon be in a post-antibiotic era. In fact, for some patients and some bacteria, we are already there." The problem【C6】______overuse. Recent research by doctors at Harvard and Women"s Hospital found that the vast majority of antibiotics【C7】______for sore throats and acute bronchitis—an illness almost always caused by a【C8】______, not bacteria—are useless. Up to 80 percent of all antibiotics used in the U.S. each year,【C9】______, are given to animals. Antibiotics are the lifeline of the meat and poultry industries, which have used drugs to domestic animals as a means of【C10】______growth and preventing illnesses caused by overcrowding and poor conditions. An increasing number of bacterial【C11】______have taken the opportunity to evolve【C12】______the reach of antibiotics. The CDC"s 2013 threat report listed 17 antibiotic-resistant microorganisms that directly cause at least 23,000 deaths each year in the U.S.【C13】______Globally, drug-resistant pneumonia is an ever-increasing threat. Reported cases have【C14】______over the past nine years, killing an estimated 170,000 people last year. Although anti-bacterial resistance can be slowed, it is【C15】______. As a result, medicine companies have found antibiotics to be less【C16】______investments than drugs for chronic illnesses, which can be used over the long term. If we don"t【C17】______our use of existing antibiotics and commit to developing new ones, the risks are not just medical, but【C18】______. The CDC estimates that, in the United States, antibiotic resistance already costs $20 billion in【C19】______health-care spend and $35 billion in lost productivity【C20】______.