In the face of growing antibiotic resistance, experts are turning back to bacteriophages, natural-born killers of bacteria. The advent of antibiotics in the 1940s led Western doctors to discontinue using phages; however, many countries in the former Soviet Union have continued to use them. "We are at risk of losing the race here," says CDC director Tom Frieden. "This has the potential to undermine much of modern medicine." An analysis commissioned by the U.K. government found that global antimicrobial resistance takes the lives of some 700,000 people annually. Failing to deal with the issue by 2050 could lead to 10 million additional deaths each year, with an economic toll of $100 trillion, the report said. A new class of antibiotics has not been seen for nearly 30 years, prompting researchers to look at phages again. Phages, discovered more than a century ago, come in many shapes and sizes. While phage therapy has not undergone rigorous clinical trials, increasing interest in them has many labs and biotechnology firms trying to research them as fast as they can. The White House last year noted phage therapy as one of a number of options when it unveiled its national plan to combat drug-resistant bacteria.