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You may have seen the news: New class of antibiotic could turn the tables in battle against superbugs. Question is what does that really mean and is it a big deal?
Antibiotics are molecules that can either kill or inhibit the growth of bacteria and are commonly used drugs against bacterial infections. Most prescribed antibiotics are naturally produced by bacteria or fungi as protection from other microbes. Studies trying to make synthetic antibiotics have failed, so screening natural bacteria strains is crucial in finding new antibiotics. The problem is that the vast majority of bacteria can’t be taken out of their natural environment and grown in the lab.
We have a range of antibiotics to treat patients with, so why do we need new ones? Because bacteria can become resistant to the drugs. You probably heard about the “deadly hospital infections” caused by MRSA. This strain of the bacteria Staphylococcus aureus is resistant against antibiotics and has become a problem in hospitals and nursing homes as it spreads quickly and can’t be treated directly. The problem has become so big that the World Health Organization (WHO) speaks of the “post-antibiotic era in which common infections and minor injuries can kill”. So yes we urgently need new antibiotics and the new research identifying new potential antibiotics is a big deal.
How did the researcher in this new study get around the problem of “unculturable bacteria”? They developed a device called iChip that allows bacteria to be grown in their natural habitat. Single bacteria are trapped between two membranes, which are then put back into the habitat, where nutrients and other factors can reach the bacteria. About 50% of the bacteria grow into colonies. A total of 10,000 colonies were screened for antimicrobial substances, identifying 25 potential antibiotics. The most promising one is called Teixobactin and is produced by Elephtheria terrae.
Teixobactin is able to kill bacteria such as MRSA and a strain of tuberculosis. Excitingly bacteria may not been able to develop a resistance against the antibiotic any time soon. Most antibiotics act against proteins, which are coded for by DNA. This DNA can mutate, changing the form of the protein and restricting the antibiotics action on the bacteria (= resistance). Teixobactin however binds two molecules (lipids) needed for the bacterial outer membrane. These lipids are produced by the cells from organic material and are not encoded in DNA – therefore it’s more difficult for the bacteria to develop a resistance!
While this is great news, we shouldn’t get too excited just yet. It will take years for the antibiotic to go through clinic trials to proof its functionality and safety in humans. However, Teixobactin can only act on one type of bacteria – so called gram(+) bacteria. The second class of bacteria, gram(-) ones, have a protective cell wall around the cells outer membrane, which cannot be targeted by the new antibiotic. Therefore, continuous research is needed to identify further effective antibiotics. This empathises the importance of the method demonstrated in this study, which allows screening on beforehand unculturable bacteria and thereby opening the door for many more new potential antibiotics to be identified.
To read the full research article by Ling et al. click here