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Phages

Young and his colleagues at Texas A&M aim to unleash bacteria's age-old nemeses called bacteriophages, or phages for short. Phages are simply viruses that infect and kill bacteria. They are ubiquitous in nature and in our bodies—astonishingly, Young notes, more than 90 percent of the DNA found in us belongs to phages. All those phages are parasitizing the trillions of resident bacteria within us; those bacterial cells outnumber our "own" by about 10 to one.



Phages do not cause human illness, but for any kind of bacterium, there are often dozens of phages that harry it. Figuring out which kinds work best and could be produced economically by drug companies will take some time, but the benefits of "phage therapy" sure look enticing.



Many phages target only a few strains or even a single species of bacteria. That's a good thing: Phages are more precise than some of today's antibiotics that kill indiscriminately, causing collateral damage in our guts by wasting good-guy bacteria. "With phages, you can target your targets rather than give yourself a broad-spectrum antibiotic," Young says. As a bonus, phages that are treating an infection crank out more phages as they replicate in the stricken bacteria. "I joke that it's the only medicine that grows," he says.



The clinical use of phages started in the 1920s and '30s, meaning it actually predated the development of antibiotics. But today, just a few countries, such as Russia and Georgia, still administer the beneficial viruses to humans, through various means including oral concoctions and via injections. What happened to phage therapy? As Young explained, phages were discovered before the advent of modern biomolecular science, and the incredible success of conventional antibiotics in the 1940s relegated phage pharmaceutical investigation to the back burner. It's hard to say when we'll see phage therapy take hold in the U.S. because of intellectual-property and FDA regulatory hurdles, but Young remains hopeful.