Mining the Soil for New Antibiotics

A new antibiotic effective against a broad range of superbugs including MRSA, which the scientists are calling Teixobactin has been discovered. Teixobactin also appears to be effective at fighting a raft of other superbugs and increasingly diffficult to treat infections including enterococci, Mycobacterium tuberculosis, Clostridium difficile and Bacillus anthracis.

Teixobactin - a new super-penicillin?

Furthermore, the scientists have been unable to detect the creation of super bug mutants even after mixing Teixobactin with these bacteria and cultivating them under normal laboratory conditions. Therefore, these early results are very exciting and have the potential to have as much impact on effective modern medicine as the discovery of penicillin itself.

According to the paper published in Nature, Teixobactin has an ability to penetrate and disrupt the bacterial cell wall defenses in otherwise drug-resistant super bugs where other antibiotics fail. This penetration by the drug through the cell wall results in cell lysis and bacterial cell death.

Earth - The Mother of Drug Invention

It is perhaps the elegance and simplicity of the scientific method to discover these new drug secreting soil bacteria that is of as much interest as the outcome. The reason for this is that the normal method for cultivating bacteria is to obtain samples from the environment and to grow them in the laboratory in petri dishes on various different types of growth media - often with a gel or agar base. The trouble is that 99 percent of all species of bugs simply cannot grow in these laboratory conditions - and they and their products are therefore not discovered.

Returning Bugs to Mother Nature

The scientists have therefore produced an ingeniouis system for separating out the individual species of unidentified bugs into separate chambers, and then returning them to their natural habitat where they can grow and thrive into larger colonies. Once a colony is formed there are then sufficient numbers of the organism to work with, identify and the products they produce (including Teixobactin) can be isolated.and then tested.

Soil Bugs - a "Precious Shared Resource".

The ability to now be able to grow the other 99% of environmental bacteria naturally provides a huge new source of drug discovery. The bacterium responsible for producing Teixobactin is called Eleftheria terrae.

The authors of the paper say: "Uncultured bacteria make up approximately 99% of all species in external environments, and are an untapped source of new antibiotics. We developed several methods to grow uncultured organisms by cultivation in situ or by using specific growth factors".

Commenting on the paper, Professor Chris Butler, Director of the Institute of Primary Care and Public Health, Cardiff University, said:“Discoveries of truly new antibiotic classes are indeed rare and to be warmly welcomed, given the inexorable rise in gram-negative bacterial resistance." He goes on to say, “While exciting, this is very early phase research and we have no idea if this agent will be safe or effective in humans. As the authors rightly point out, resistance usually does emerge to new antibiotics, so if future trials show that this antibiotic is suitable for widespread use in humans, we have to treat it as a precious shared resource.”

Professor Timothy Walsh, Institute of Infection and Immunity, Cardiff University,