New antibiotic family kills superbugs in a way they can't resist

Antibiotic-resistant bacteria are poised to become a global health concern in the coming decades. In the race to develop new weapons, scientists from Texas A&M have created a novel family of antibacterial polymers that can kill 'superbugs' in a way they can't evolve resistance to.

The discovery of penicillin was one of the most important scientific breakthroughs of the 20th century. Suddenly infections were far more survivable, with antibiotics opening up more surgical and medical treatments to more people. But the arms race was just beginning.

Bacteria are adaptable little pests, and so they quickly evolved defenses against antibiotics. Scientists in turn developed new ones, but of course bacteria soon evolved resistance to those too, in a cycle that lasted decades. Unfortunately, in recent years the tides have begun to turn in favor of bacteria – we’re running out of new drugs, but they’re not running out of evolution. Our last lines of defense are beginning to fail, and there are now strains of superbugs that are immune to anything and everything we can throw at them.

We need brand new tactics if we’re going to prevent a global health crisis, and antibiotic polymers are a decent step in that direction. These synthetic molecules latch onto and disrupt the outer membranes of bacteria, in a form of attack that the bugs can’t develop resistance to.

In the new study, the Texas A&M team developed new polymers that are more customizable, allowing them to be tuned to fight superbugs even more effectively. The key is a catalyst called AquaMet, which can handle a high concentration of charges and is water-soluble. That charge tolerance is important – antibacterial polymers work because their positive charge attracts them to the negative charge of the bacteria.

The team’s new method of making these polymers allows for more precise placement of where particular parts can be added to the molecule, which previous work has suggested could improve their performance.

In lab tests, the new polymers were found to be active against the two main groups of bacteria – gram-positive, such as Methicillin-resistant Staphylococcus aureus (MRSA), and gram-negative, such as E. coli. This suggests the molecules will work against a variety of superbugs. Importantly, the drugs also worked at low concentrations.

The main complication of antibacterial polymers is that red blood cells also have a negative charge, meaning the drugs can be attracted to them too. But in this case, the team’s method of more customization of the molecules allowed them to be more selective for bacteria. This area does still need more work though, the team says, which is the current focus of the next round of research.

The research was published in the journal PNAS.

Source: Texas A&M University