Chart via The Dish. Think Progress offers this explanation:
The director of the Centers for Disease Control and Prevention (CDC), Dr. Tom Frieden, recently pointed out that if we don’t act on this issue soon, “our medicine cabinet will be empty and we won’t have the antibiotics we need to save lives.”That doesn't mean that we have no new antibiotics, because there are varieties of drugs within these classes. But when organisms develop drug resistance, it often spans the entire class.
Nonetheless, research in this area has largely stalled, and only a handful of new antibiotics have been created over the past decade. That’s partly because it isn’t as profitable for pharmaceutical companies to invest in creating new drugs. Last year, the U.S. government formed a partnership with a pharma giant in the hopes of spurring innovation. Some infectious disease experts are urging Congress to pass tax credits to encourage the development of new antibiotics.