A new antibiotic – the first in nearly 30 years – has been discovered by scientists who claim it appears to be as good, or even better, than many existing drugs with the potential to work against a broad range of fatal infections such as pneumonia and tuberculosis, reports The Independent.
Laboratory tests have shown the new antibiotic, called teixobactin, born from a new way to tap the powers of soil micro-organisms, can kill some bacteria as quickly as established antibiotics and can cure laboratory mice suffering from bacterial infections with no toxic side-effects.
Studies have also revealed the prototype drug works against harmful bacteria in a unique way that is highly unlikely to lead to drug-resistance – one of the biggest stumbling blocks in developing new antibiotics.
Such a development would represent a huge boost for medicine because of growing fears that the world is running out of effective antibiotics given the rapid rise of drug-resistant strains of superbugs and the spread of these diseases around the globe.
Professor Kim Lewis of Northeastern University in Boston – who led the research and is working with NovoBiotic Pharmaceuticals, which owns the patents on teixobactin – said that the first clinical trials on humans could begin in two years and, if successful, the drug could be in widespread use in 10 years.
"The problem is that pathogens are acquiring resistance faster than we can develop new antibiotics and this is causing a human health crisis. We now have some strains of tuberculosis that are resistant to all available antibiotics," Lewis said.
"Teixobactin is highly effective against tuberculosis and there is an opportunity to develop a single-drug treatment against tuberculosis based on teixobactin rather than a treatment regime based on administering three different antibiotics."
Test-tube studies showed that teixobactin was able to kill bacteria as quickly as the antibiotics vancomycin and oxacillin.
Scientists at the University of Bonn in Germany have shown that teixobactin works in a unique way by binding to the fatty lipids that form the building blocks used by bacteria to manufacture their cell walls.
"This binding site represents a particular Achilles heel for antibiotic attack and this may also explain why resistance to teixobactin was not detected," said Tanya Schneider of Bonn University.
Professor Lewis said that the failure to detect any signs of resistance to teixobactin establishes a new paradigm in the development of antibiotics, which had assumed resistance will eventually occur.
"Bacteria develop resistance by mutations in their proteins. The targets of teixobactin are not proteins, they are polymer precursors of cell wall building blocks so there is really nothing to mutate," Lewis said.
"We've been operating under the dogma that the development of resistance is inevitable and we need to focus on introducing antibiotics faster than pathogens can acquire resistance," he said.
Because resistance can evolve quickly, the high costs of drug development aren't seen as having long-term value, and fewer new antibiotics are reaching the market.
Part of the problem, says a Smithsonian Mag report, has been trouble growing the most promising candidates in the lab. Natural microbial substances from soil bacteria and fungi have been at the root of most antibiotic drug development during the past century. But only about one percent of these organisms can be grown in a lab. The rest, in staggering numbers, have remained uncultured and of limited use to medical science, until now.
Lewis and his team decided on a different approach. "Instead of trying to figure out the ideal conditions for each and every one of the millions of organisms out there in the environment, to allow them to grow in the lab, we simply grow them in their natural environment where they already have the conditions they need for growth," he says. To do this, the team designed a gadget that sandwiches a soil sample between two membranes, each perforated with pores that allow molecules like nutrients to diffuse through but don't allow the passage of cells. "We just use it to trick the bacteria into thinking that they are in their natural environment," Lewis says.
The team isolated 10,000 strains of uncultured soil bacteria and prepared extracts from them that could be tested against nasty pathogenic bacteria. Teixobactin emerged as the most promising drug. Mice infected with bacteria that cause upper respiratory tract infections (including S. aureus or Streptococcus pneumoniae) were treated with teixobactin, and the drug knocked out the infections with no noticeable toxic effects.
The research suggested there may be many more novel antibiotics waiting to be discovered in the "great mass of uncultured soil bacteria", said Prof Marc Mendelson, head of infectious diseases at the University of Cape Town in a Business Day report. On the flip side, he said: "this antibiotic has no activity against gram-negative bacteria, which comprise the majority of the current superbugs of which the international community is most concerned." Gram-negative bacteria include Klebsiella and E coli.
The development pipeline for antibiotics targeting gram-negative bacteria was "not so much dry as parched", he said.
The public health threat of resistance was highlighted last year in a World Health Organisation report that warned the world was entering a "post-antibiotic era". The UK's chief medical officer, Sally Davies, has put antibiotic resistance on the UK government's national risk register, alongside terrorist attacks and pandemic flu, and warned that without new antibiotics, more people will die after routine operations in the next 20 years.
[link url="http://www.independent.co.uk/life-style/health-and-families/health-news/first-new-antibiotic-in-30-years-could-be-key-to-beating-superbug-resistance-9963585.html"]Full report in The Independent[/link]
[link url="http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14098.html"]Nature abstract[/link]
[link url="http://www.smithsonianmag.com/science-nature/new-antibiotic-dirt-soil-can-kill-drug-resistant-bacteria-180953828/?no-ist"]Full Smithsonian Mag report [/link]
[link url="http://www.bdlive.co.za/national/health/2015/01/08/drug-resistant-tb-might-meet-its-match"]Full Business Day report [/link]
[link url="http://www.theguardian.com/science/2015/jan/07/antibiotic-drug-resistance-teixobactin"]Full report in The Guardian[/link]
[link url="http://apps.who.int/iris/bitstream/10665/112642/1/9789241564748_eng.pdf?ua=1"]WHO report[/link]