Grapevine

Phage cocktail shows promise against drug-resistant bacteria

Researchers have a new battle tactic to fight drug-resistant bacterial infections. Their strategy involves using collections of bacteriophages, viruses that naturally attack bacteria. In a new study, researchers at the University of Chicago Pritzker School of Molecular Engineering (PME) and UChicago Medicine have shown that a mixture of these phages can successfully treat antibiotic-resistant Klebsiella pneumoniae infections in mice.

At the same time, however, the team's work revealed just how complex the interactions between phages and bacteria can be; the viruses predicted to be most effective in isolated culture dishes did not always work in animals. Moreover, both phages and bacteria can evolve over time—in some cases, phages evolved to be more efficient in killing bacteria while in other cases, Klebsiella evolved resistance to the phages.

"We still think phages are an incredibly promising approach to treating drug-resistant bacteria such as Klebsiella," said Mark Mimee, assistant professor of molecular engineering and senior author of the new work, published in Cell Host & Microbe. "But phages are like a living, constantly changing antibiotic which gives them a lot of complexity."

Klebsiella pneumoniae are common bacteria found in people's intestines where they cause little harm. However, when the bacteria escape to other body sites, such as open wounds, the lungs, the bloodstream, or the urinary tract, they can cause more severe infections. K. pneumoniae are often spread within hospital settings, and drug-resistant strains have become common.

"In my clinic, I see patients with recurrent urinary tract infections caused by Klebsiella," says urogynecologist Sandra Valaitis, MD, of UChicago Medicine, a co-author of the new work. "Often these bacterial strains develop resistance to oral antibiotics, leaving patients with fewer options to clear the infection. We urgently need new ways of treating these bacteria."