This is a perfect example of the effect of “evolution”-the use of antibiotics to expose bacteria to environmental pressures means that only the most powerful bacteria can survive. Eventually, the resistance genes spread so widely that the drugs no longer have any effect on the species. This forces us to use other drugs, and this pattern is constantly repeated. Now, as our last line of defense begins to fail and it is predicted that millions of people will die every year by 2050, it looks like we are losing this “arms race.”
While developing new antibiotics, scientists are looking for ways to make old antibiotics work again. This includes modifying drugs, pairing them with other antibiotics or probiotics, or using peptides to weaken the bacteria in the first place. This new discovery is a bit like the last method.
Researchers from the University of Leeds, Southern University of Science and Technology of China, and Fudan University have created a new antibacterial “weapon” with some existing things. Its core is a nanocluster composed of about 25 gold atoms, and people have been studying its antibacterial properties for a long time.
The gold nanoclusters are packaged in a molecular envelope to help them reach the bacteria without harming the host cell. This envelope is composed of two ligands-the first ligand has a positive charge and is attracted by the negative charge of the bacteria, and the second ligand is a so-called oligomer, which contains both positive and negative charges. Since these are also present in mammalian cell membranes, this helps packaging ignore the host. Once its work is done, it also helps it pass through the kidneys and excreted through the urine.
The researchers’ idea is that these ligands will help deliver the package to the bacteria, and then the gold nanoclusters will start working, destroying the bacterial membrane. This may not be enough to kill them directly, but it should be enough to weaken them so that antibiotics can fight them-even if these bacteria have developed resistance to them.
The team tested this technique on mice, using a common hospital-obtained superbug called methicillin-resistant Staphylococcus epidermidis (MRSE). They treated these bacteria with three different classes of antibiotics, including with and without gold nanoclusters. Sure enough, those antibiotics paired with gold performed better, and the amount of drug required to inhibit MRSE was only 1/128 of that when administered alone.
This technology can help buy some time to develop new antibiotics and inject new vitality into old antibiotics.
The research was published in《Chemical Science》In the magazine.