Bacteria are tiny cells that can enter the human body and cause infections that make humans sick. In order to get better, the body needs to kill or stop the growth of these bacteria. Doctors give medicines called antibiotics to help the body get rid of an infection. Penicillin is a common antibiotic often used to stop bacteria from growing. It does this by preventing the bacteria from building a cell wall, which makes it difficult for it to grow and reproduce. However, bacteria can build resistance, or develop a defense against antibiotics. This makes the antibiotic less effective at killing the bacteria.
Humans are currently overusing antibiotics, and as a result there are more antibiotic-resistant bacteria. Penicillin, and other antibiotics in the same family, are becoming less effective at killing bacteria. Therefore, scientists have to find a new kind of antibiotic that will stop the growth of bacteria in other ways. One current approach is to disrupt cell division, which prevents bacteria from being able to divide.
For bacteria to grow, it first needs to reproduce. It does this by dividing into two daughter cells that have the same DNA. For the cell to divide, a special enzyme called autolysin has to bind to the cell wall and break it down. Once the cell wall is broken, the cells can then divide. If autolysin is disrupted or is not functioning properly, cells cannot divide.
Corbomycin is a compound found in soil bacteria. It works by attaching to the bacterial cell wall and preventing autolysin from binding. As a result, bacterial cells cannot divide and are essentially “trapped” within their own cell walls. Eventually the bacteria die, stopping the infection. Scientists have used corbomycin as an antibiotic for bacteria that are resistant to other antibiotics, and have found that it can effectively kill those bacteria. This gives us a new weapon in our fight against bacterial infections.Edit Summary
“We show that by binding to peptidoglycan, complestatin and corbomycin block the action of autolysins—essential peptidoglycan hydrolases that are required for remodelling of the cell wall during growth. Corbomycin and complestatin have low levels of resistance development and are effective in reducing bacterial burden in a mouse model of skin MRSA infection.” (Culp et al. 2020: 582)
“We examined the phenotype of B. subtilis grown in sub-MIC levels of antibiotic. At 0.6 × MIC, cells effectively formed septa but failed to divide, instead forming twisted and knotted chains of cells (Fig. 2f)… This distinctive phenotype was unlike that observed with several control antibiotics (Extended Data Fig. 4b), but matched that of B. subtilis strains defective in autolysins. This diverse group of peptidoglycan-degrading enzymes is essential for normal peptidoglycan metabolism by enabling the insertion of new material into the existing cell wall and the cleavage of peptidoglycan at the division septa.” (Culp et al. 2020: 584)
“Antibiotics blocking nearly every step in peptidoglycan synthe-sis have been described, but—to our knowledge—complestatin and corbomycin are the first to inhibit peptidoglycan remodelling… The finding that corbomycin and complestatin inhibit most or all autolysins by binding peptidoglycan thus represents the discovery of antibiotics with a long-sought-after mechanism of action. Corbomycin and complestatin are active against multidrug-resistant clinical isolates, display low resistance development and are effective in vivo in a mouse model of skin infection, making them an exciting avenue for future development.” (Culp et al. 2020: 587)