Have you heard of kanglemycins? These newly discovered antibotics were found by examining organisms from dirt. In 2018 we are still at a primitive stage where most of us can not engineer safe cures for common diseases. As pathogenic microbes have evolved, thanks in part to our overuse of antibiotics, our arsenal of antibiotics have become less effective. Scientists have started looking elsewhere, including to beneficial microbes, for help.
… Rates of rifamycin resistance are steadily rising, which presents a major problem to doctors attempting to treat TB. But, according to a new study from a team of Rockefeller scientists, nature might have come up with a solution. The study, published in Nature Communications, suggests that an antibiotic found in dirt can destroy mutant mycobacteria.
Rifamycin, or Rif, works by targeting RNA polymerase (RNAP), an enzyme crucial to bacteria’s survival. Resistance develops when the genes coding for RNAP mutate: Even a small genetic change can prevent Rif from binding to the enzyme and obstructing its function.
To circumvent resistance, researchers needed a drug that acted like Rif, but that could bind to RNAP, even in the presence of mutations. And while some scientists might turn to the lab to synthesize such a molecule, Sean F. Brady, the Evnin Professor, turned to the environment.
“Rifamycin is naturally produced by a bacterium,” he says. “So I wanted to find out whether nature had also made Rif analogs — molecules that look like rifamycin, but that have slight differences.”
To identify any such analogs, Brady’s lab sequenced the genes of microbes found in soil samples collected from locations across the country. They hoped to uncover antibiotics that were genetically related to Rif, but with small variations that allowed them to bind to mutated RNAPs.
That’s exactly what they found.
Through their soil probes, the researchers discovered a group of natural antibiotics, known as kanglemycins, or kangs, that share most of their genes with rifamycin. Moreover, analyses by postdoctoral associate James Peek revealed that these antibiotics are capable of combatting bacteria that don’t respond to Rif.
Brady hypothesizes that kangs might have emerged in response to evolutionary pressures that mirror those present in hospitals. In a clinical setting, bacteria react to antibiotic onslaught by evolving protective mutations. In turn, researchers create more powerful antibiotics; and, over time, bacteria develop further mutations to evade these new attacks. In nature, Brady postulates, bacteria and antibiotics may engage in a similar arms race.
Bacteria in dirt compete with one another. And one way for a bacterial species to take out the competition is to produce toxins, like Rif, which act as natural antibiotics. Like bacteria in hospitals, bacteria in soil respond to such threats by mutating in ways that confer resistance to the toxins. But, in time, their rival bacteria might also mutate, producing yet stronger antibiotics. Kangs, speculates Brady, may be the result of this kind of competition. …
I hope we will progress to where the average person can easily and safely get rid of any microbes not playing well with human cells. It could happen.