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New Antibiotic Offers Hope Against Resistant Bugs

Newly discovered bacterium Eleftheria terrae makes an antibiotic that could be a new weapon against resistant infections. (William Fowle/Northeastern University)

International public health officials have expressed alarm that once highly-effective antibiotics, developed in some cases more than 50 years ago, are losing the war against dangerous infections, allowing once treatable diseases to grow into deadly illnesses worldwide — so-called "superbugs."

These include the bacterium that causes tuberculosis, which silently infects up to one-third of the world’s population. It can spring to life and cause active disease, and a sometimes fatal skin infection called methicillin-resistant Staphylococcus aureus, or MRSA, that is spread through hospitals, clinics and nursing homes.

But a new antibiotic discovered by an international team of researchers is unlikely to fail where other drugs have.

Called Teixobactin, it is made by Eleftheria terrae, one of 10,000 previously untested bacterial strains found in soil. The compound is manufactured by the company Novo Biotic.

According to Kim Lewis, director of the Antimicrobial Discovery Center at Northeastern University in Boston, Massachusetts, traditional antibiotics, also developed from soil microbes, work by binding to bacterial proteins that are essential for the microbe to thrive.

After a while, Lewis says, many bacteria adapt themselves to the drugs and develop avoidance mechanisms.

“Mutations occur, the protein changes and the antibiotic no longer binds," said Lewis, lead author of the study describing the new antibiotic compound in the journal​ Nature. "The targets of teixobactin are not proteins. It hits two different targets. These targets are precursors of cell wall polymers and they do not mutate. There is nothing to mutate. So, at least by that common mechanism, resistance does not occur.”

Teixobactin destroys bacteria by causing their cell walls to break down.

The compound was tested in mice infected with three aggressive pathogens — Clostridium difficile, Mycobacterium tuberculous and Staphylococcus aureus — and it cleared the infections.

For experts such as Ontario-based Gerry Wright of McMaster University, teixobactin and drugs like it are long overdue.

“If you find a new antibiotic, you want to be able to find something that there’s not a lot of existing resistance to, or that resistance will be hard to get," said Wright, who drafted an accompanying analysis of Lewis’s work in Nature. "And so, mission accomplished, in that case. We don’t know if it’s going to be a drug, but [Lewis] is on his way trying to see if it might be.”

At the earliest, it’s estimated that teixobactin and drugs in the same class will not become available for at least five years, pending more animal tests and human clinical trials.