from the dust-to-dust dept.
Drug resistant strains of many diseases are emerging faster than new antibiotics can be made to fight them with drug-resistant bacteria infecting at least two million people a year in the United States and killing 23,000. Now Denise Grady reports at the NYT that scientists have developed a new method, which extracts drugs from bacteria that live in dirt, that has yielded a powerful new antibiotic, teixobactin, that was tested in mice and easily cured severe infections, with no side effects. Better still, the drug works in a way that makes it very unlikely that bacteria will become resistant to it. And the method developed to produce the drug has the potential to unlock a trove of natural compounds to fight infections and cancer — molecules that were previously beyond scientists’ reach because the microbes that produce them could not be grown in the laboratory.
The new research is based on the premise that everything on earth — plants, soil, people, animals — is teeming with microbes that compete fiercely to survive. Trying to keep one another in check, the microbes secrete biological weapons: antibiotics. “The way bacteria multiply, if there weren’t natural mechanisms to limit their growth, they would have covered the planet and eaten us all eons ago,” says Dr. William Schaffner. The problem is that about 99 percent of the microbial species in the environment are bacteria that do not grow under usual laboratory conditions (PDF). But the researchers have found a way to grow them using a process that involves diluting a soil sample and placing it on specialized equipment. Then, the secret to success is putting the equipment into a box full of the same soil that the sample came from. “Essentially, we’re tricking the bacteria,” says Dr. Kim Lewis. Back in their native dirt, they divide and grow into colonies. Once the colonies form, the bacteria are “domesticated,” and researchers can scoop them up and start growing them in petri dishes in the laboratory.
Experts not involved with the research say the technique for isolating the drug had great potential. They also say teixobactin looked promising, but expressed caution because it has not yet been tested in humans. “What most excites me is the tantalizing prospect that this discovery is just the tip of the iceberg,” says Mark Woolhouse. “It may be that we will find more, perhaps many more, antibiotics using these latest techniques.”
University of Sheffield and Rutherford Appleton Laboratory (RAL) scientists have discovered several new related (dinuclear RuII) compounds which visualize and kill gram-negative bacteria, such as E. coli (note - no word on whether it works on synthetic E.coli)
Bacteria are classified generally by what type of staining works on them using a method developed in the 1800's by Hans Christian Gram. 'Gram-negative' bacteria retain a stain color that shows them as a pinkish red coloring, these bacteria have cell walls that make it difficult to get drugs into them and many gram-negative bacteria have become significantly or even completely resistant to available drug treatments.
A new drug in the difficult gram-negative space is particularly important. Drug resistant bacteria already cause the deaths of over 50 thousand people a year in the US and EU alone, and as many as 10 million people a year could die worldwide every year by 2050 due to antibiotic resistant infections.
Doctors have not had a new treatment for gram-negative bacteria in the last 50 years, and no potential drugs have entered clinical trials since 2010.
The new drug compound has a range of exciting opportunities. As Professor Jim Thomas explains: "As the compound is luminescent it glows when exposed to light. This means the uptake and effect on bacteria can be followed by the advanced microscope techniques available at RAL.
"This breakthrough could lead to vital new treatments to life-threatening superbugs and the growing risk posed by antimicrobial resistance."
The studies at Sheffield and RAL have shown the compound seems to have several modes of action, making it more difficult for resistance to emerge in the bacteria.
Mammalian cell culture and animal model studies indicate that the complex is not toxic to eukaryotes, even at concentrations that are several orders of magnitude higher than its minimum inhibitory concentration (MIC).
The researchers plan to test the compounds against additional multi drug resistant bacteria next.