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Featured lecture:  The Quest for Novel Antibiotics

Featured lecture: The Quest for Novel Antibiotics

Dr. Kim Lewis, University Distinguished Professor and Director, Antimicrobial Discovery Center
Department of Biology, Northeastern University

By Lauren Baggett

Dr. Kim Lewis and his colleagues at Northeastern University’s Antimicrobial Discovery Center have rejuvenated the search for antibiotics that act in new ways.

“We were dry for a very long time, and now we have a new source,” said Lewis. So we’re back in the game.

Much like finding a new oil reservoir, Lewis’ team found a way to identify potential antimicrobial compounds in previously un-mined sources.

Lewis’ team developed a device called the iChip that sheds light on what he called “dark matter” microbes, the 99 percent of bacteria scientists had been unable to examine because they were so difficult to culture in the laboratory. The device is about the size of a USB drive, and when embedded in a natural setting it can be used to cultivate bacteria in their natural habitat, rather than in a petri dish.

The new device’s first big score is teixobactin, which in lab tests kills numerous types of Gram-positive bacteria.

This broad category of pathogens includes Staphylococcus aureus and Streptococcus pneumoniae. Most exciting, teixobactin been shown to kill MRSA (methicillin-resistant Staphylococcus aureus) in mice.

The demand for new types of antibiotics is intense because pathogens are outwitting existing drugs at a great rate.

Teixobactin’s novel mechanism of action may explain why it will be harder for disease-causing bacteria to escape. Unlike typical antibiotics, teixobactin binds to the pathogen’s cell wall. The bacteria can’t easily alter such a fundamental part of its structure without damaging itself.

Teixobactin, said Lewis, challenges the long-held belief that pathogens will eventually develop resistance to every antibiotic. “This compound stops the rat race.”

But the race is far from finished. The antibiotic won’t be ready for human testing for another two or three years, Lewis said, and researchers can’t know whether it is a safe and effective until those results are in.

Dampening widespread enthusiasm for teixobactin, which began in January when its discovery was published in Nature, is that it has no activity against Gram-negative bacteria.

Organisms in this category complicate surgical wound sites and are responsible for bloodstream infections, pneumonia, and meningitis. E. coli, for example, falls into this category.

Lewis’ team is currently using the iChip to look for potential antibiotics that may prove effective against Gram-negative bacteria.

Lewis reviewed his lab’s pursuit of novel antibiotics at the 2015 UGA Conference on Drug Discovery on November 19th.

Lauren Baggett is a first-year graduate student in health and medical journalism at UGA’s Grady College of Journalism and Mass Communication and a reporter for Graduate Newsroom.