The recent release of a report titled, Vital Signs: Containment of Novel Multidrug-Resistant Organisms and Resistance Mechanisms from the CDC on drug-resistant organisms illustrates the pressing need for new antibiotics. “The emergence and spread of antibiotic resistance threatens to outpace the development of new antibiotics.” This report speaks about ‘nightmare’ bacteria (these are normal bacteria that have developed the ability to produce enzymes that work against antibiotics), their proliferation across the continent, and the ways to help curb the spread of them.

Coverage of this report has been huge; I think every major news agency has written something about it. There is nothing like a story of horrible killer bacteria to boost your readership. The findings are scary but also stated was the need for quick response to stop the spread before it becomes unrestrainable and the need for new antibiotics in the arsenal. Despite this health crisis, no new antibiotics have been produced in 30 years.

Many people are afraid of all things ‘dirty’ but new studies are being done with soil in the hunt for new antibiotics. Teixobactin is a peptide-like secondary metabolite found in some bacteria that kills Gram-positive bacteria such as Staphylococcus aureus and Mycobacterium tuberculosis, among others. Teixobactin works as an inhibitor of cell wall synthesis which leads to the breakdown of the vulnerable bacteria. This substance was synthesized and used to successfully treat a bacterial infection in mice.

Study and development of Teixobactin continues. Clinical trials are still necessary before it can be made available to the public

One recent study has made some interesting discoveries about malacidins. Malacidins are a class of chemicals made from bacteria found in normal healthy soil and are known to kill Gram-positive bacteria. These chemicals were discovered at Rockefeller University by researchers Brad Hover, Sean Brady, and team in 2018 and their findings were published in the journal Nature Microbiology. They had been looking into antibiotics related to daptomycin, an antibiotic used in the treatment of systemic and life-threatening Gram-positive infections, and their need of calcium to do what they do.

These studies went about things a little differently too. Instead of using the usual way of culturing bacteria in the lab, the researchers extracted DNA from around 2000 soil samples to build their library and pinpoint the sequence of genes needed to make the malacidins. This DNA could be inserted into lab-cultured bacteria which then would make the chemicals needed to fight bacteria such as methicillin-resistant Staphylococcus aureus (MRSA).The paper also showed that malacidins were only effective in killing Gram-positive bacteria, not Gram-negative bacteria.

As of now, there has not been anything further done in the development of a usable antibiotic and it would take millions of dollars and many years to do so. The good news is that this discovery is proof of principle and that there is an untapped world of discovery in the earth.

There is another isolated strain from soil in Asia called NK2 that has shown potent antimicrobial tendencies and I am sure there is many more that I have not even touched upon in this short blog.

One thing that has become apparent is that more study needs to be done in the area of bacteria, soil biome, and biodiversity. There is evidence that points to the soil being the place where drug-resistant bacteria lives and reproduces but also where we will find the next fighter of such microbes. We need to learn as much as possible about the bacteria living in soil. After hearing about drug-resistant bacteria for so long, it is now good to hear that there may be new ways of fighting them right below our feet.

–Janice Willson

References:
https://en.wikipedia.org/wiki/Malacidin
https://www.cdc.gov/mmwr/volumes/67/wr/mm6713e1.htm?s_cid=mm6713e1_w
http://www.nature.com/articles/nature14098

*Photo source: Rizzelli Stefania (Wikimedia Commons), bacteria in dairy products

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