Every year, around 700,000 people are estimated to die from drug-resistant infections thanks to our overuse of antibiotics both in agriculture and medicine. With this figure estimated to grow into the millions within the coming decades, researchers are scrambling to find new ways to treat infections. Now, researchers from Justus Liebig University Giessen have discovered a new peptide from the gut of a parasitic worm that may be able to help.
Known as Darobactin, the peptide works against gram negative bacteria which, due to their highly restrictive cell walls, are immune to most antibiotics. Gram negative bacteria are common; examples including Escherichia coli (E. Coli) and Klebsiella pneumoniae (pneumonia) which have become immune to most treatment due to this cellular feature, thus prompting heavy research into tackling gram negative bacteria.
The epitome of two years of research, Darobactin emerged as a possible antibiotic from analyzing the Photorhabdus bacteria, found in the gut of a small parasitic worm known as a nematode. The worm first caught researchers attention due to its ability to feed on insects, targeting their larvae and releasing bacteria that combat pathogens similar to those present in the human gut. Isolating the worm’s gut bacteria, the researchers were then able to find Darobactin which, after screening, was then experimented with to treat bacterial infections common in humans.
So far, usage of the peptide has been successful. In experiments with mice, it has successfully managed to eradicate several bacterial strains including previously antibiotic-resistant strains of E Coli and pneumonia. From examining it in the lab, researchers saw that it works by binding to the BamA protein, found on the external membrane of gram negative bacteria. This then leads the bacteria to malfunction, and eventually die off.
According to Professor Till Schaeberie from the Institute of Insect Biotechnology, “"It is particularly interesting to note that this previously unknown weak point is located on the outside of the bacteria where substances can easily reach it."
Although Darobactin shows a lot of promise as an upcoming antibiotic, as human trials have yet to be conducted, it will take some time for the peptide to be able to treat human infections. Despite this however, the researchers remain optimistic that their experiments with Darobactin demonstrate a clear potential for its development as a therapeutic.