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Scientists have discovered an antibiotic capable of fighting infections that kill hundreds of thousands of people each year, a breakthrough that could lead to the field's first major new drug in more than a quarter-century.
The experimental drug, which was isolated from a sample of New England dirt, is called teixobactin. It hasn't yet been tested in people, though it cured all mice infected with antibiotic-resistant staphylococci bacteria that usually kills 90 per cent of the animals, according to a study published on Thursday in the journal Nature. Bacteria appear to have a particularly difficult time developing resistance to the drug, potentially overcoming a major problem with existing antibiotics.
"It should be used, if it gets successfully developed, as broadly as possible, because it is exceptionally well-protected from resistance development," said Kim Lewis, one of the study's authors and a professor at Northeastern University in Boston. Lewis estimated that it may take more than 30 years for bacteria to become resistant to teixobactin. He is also a co-founder of NovoBiotic Pharmaceuticals LLC, which is developing the drug.
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Teixobactin strikes multiple targets, including cell walls, said Tanja Schneider, a lead author of the study and professor at the University of Bonn in Germany. Since the lipid structures it attacks don't evolve as quickly as frequently mutating proteins, it may take the bacteria longer than usual to develop a survival tactic.
"Not only one target is attacked by teixobactin but multiple targets, and they are all lethal," Schneider said on a conference call with reporters. For bacteria it will be "very hard to modify this target, especially this part of the molecule that's bound by teixobactin," she said.
The last major new antibiotic, daptomycin, was discovered in the 1980s by Eli Lilly & Co. After being abandoned in early testing, the drug was licensed by Cubist Pharmaceuticals Inc in 1997 and approved for sale in 2003. Merck & Co last year agreed to buy Cubist for $8.4 billion.
Antibiotic-resistant bacteria kill at least 700,000 people a year, according to a UK government review. Unchecked, those infections could lead to 10 million more deaths a year by 2050, the report found.
Many antibiotics are found in natural settings, sending drug researchers to rainforests, caves, or in the case of Cubist's drug, the almost 17,000-foot Mount Ararat in Turkey, to hunt down potential treatments. The scientists, who discovered the producer of teixobactin in a grassy field in Maine, used a new technique that cultivates bacteria in the lab using environments that mimic natural habitats.
"Some of the antibiotics are from exotic places, but the reason for that - there's no scientific basis," Lewis said in a phone interview on Thursday. "Common soils such as in a field, either tilled or grass, gives you a very nice variety of all types of creatures. And a lot of isolates in the collection come from the backyard of Losee Ling, from NovoBiotic, and she lives in Lexington, Massachusetts." Ling is the company's head of research and development.
The team has looked at 10,000 bacteria strains so far and along with teixobactin uncovered more than 20 new antibiotics, Lewis said during the press conference. "This is a promising source in general for antibiotics and has a good chance of reviving the field."
The drug worked best against what are known as gram-positive bacteria, which have weaker cell walls and includes streptococcus and MRSA. Gram-negative bacteria have stronger walls and include pathogens such as E coli.
Teixobactin was also able to successfully attack drug-resistant strains of tuberculosis, which is neither clearly gram-positive nor gram-negative. The researchers are working on adaptations to make teixobactin effective against gram-negative cells as well.
It may take five to six years and hundreds of millions of dollars to bring the antibiotic to market, Lewis said.
"We've been seeing very high numbers for introducing the drug, between $1 to $2 billion, but part of that calculation takes into account the cost of failure," Lewis said in the press briefing. "In this case we have not been spending a lot of money so far and I think it will be in the low hundreds of millions to develop."
