New Antibiotic Will Better Fight Super Bugs

A new class of antibiotic may offer new hope in the battle against the growing number of drug-resistant super bugs. Scientists reported their novel discovery of teixobactin—an antibiotic that appears resistant to resistance, in a recent issue of the journal Nature.

“With the rise of resistant bacterial infections, the development of new antibiotics is critical,” says study co-author Amy Spoering, PhD, Director of Biological Research at NovoBiotic Pharmaceuticals in Cambridge, Mass.
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Because many of the antibiotics still used today were discovered decades ago, microbes have been able to evolve into resistant strains that do not respond to them. This has made it increasingly difficult to treat bacteria that cause common infections, such as urinary tract infections, pneumonia, and bloodstream infections.

Using a device called a “diffusion chamber,” the scientists developed a way to culture bacteria in their natural environment, which allowed them to tap into previously uncultured bacteria. They repeatedly used the diffusion chamber to culture different species of soil bacteria and tested about 10,000 bacterial colonies.

From these, the team discovered 25 potential antibiotics that could stop the growth of S. aureus—the most powerful of which was teixobactin.

In the lab, it showed success in killing a broad panel of bacterial pathogens, including the drug-resistant super bugs methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). And further testing in mouse models showed promising results against bacteria that cause septicemia, skin, and lung infections.

“Teixobactin is active against gram positive-pathogens,” Spoering says. “The mechanism of action of teixobactin is unique—it hits multiple essential targets of cell wall synthesis.”

The compound works by breaking down the bacterial cell wall, which makes it very difficult for the pathogens to mutate into resistant strains. In fact, the researchers were unable to generate resistant mutants to teixobactin. “Given its mechanism of action, we anticipate that it will take a long time to develop resistance in the clinic,” Spoering says.

The authors concluded, “The properties of this compound suggest a path towards developing antibiotics that are likely to avoid development of resistance.”

Spoering says the drug is currently in preclinical development and allergy profiles have not yet been determined. “The next steps include safety testing in animals and additional efficacy animal studies,” she says. “We are at least 2 years from the clinic.”

—Colleen Mullarkey

Reference

Ling LL, Schneider T, Peoples AJ, Spoering AL, Engels I, Conlon BP, et al. A new antibiotic kills pathogens without detectable resistance. Nature. 7 January 2015. [Epub ahead of print].