Via The Guardian: The ‘superantibiotics’ that could save us from bacteria apocalypse. Excerpt:
Such is the speed at which bacteria can adapt and evolve, that even when they re-engineer existing antibiotics, scientists face a challenge to get a drug that will last for decades, rather than a few years. During the past 50 years, we have already redesigned some of the earliest antibiotics, such as penicillin and fluoroquinolones several times.
But we are now on to the fourth generation of penicillins, and newly resistant bacterial strains are never far away. “These drugs are more fragile because even the newer versions are still based on binding to different combinations of enzymes,” says Dale Boger, a chemical biologist at the Scripps Research Institute.
Instead, scientists believe durability can be achieved either by a killing mechanism, or by creating antibiotics with so many different killing mechanisms that the probability of bacteria developing a mutation is much lower. First developed in 1958, vancomycin is one of the so-called “last resort” antibiotics, reserved for the most dangerous infections where virtually nothing else will work.
But during the past two decades, the rise of vancomycin-resistant bacteria has caused increasing consternation, prompting Boger and scientists at the Scripps Institute to attempt to create a super-form of vancomycin by engineering three new killing mechanisms into the original drug. Advertisement
The result of their work, published earlier this year, is vancomycin 3.0, a drug that is 25,000 times more potent than before against previously resistant bacteria. The challenge is now to transform this elaborate molecule into something that can be made cheaply and on a vast scale. But Boger believes it may have the potential to last the test of time.
“It’s hard to imagine a bacterium simultaneously making changes that could overcome three different mechanisms,” he says. “So the durability should be extremely high.”
One of the advantages of using vancomycin as the basis for creating a more durable antibiotic was that the original drug was already fairly robust. After 60 years, bacteria had only evolved one method of resistance. Boger believes the way forward is to take other robust antibiotics and add in mechanisms that make them even stronger. “There are great candidates to develop and re-engineer, and then you’d have a whole line of new drugs for which resistance would be very difficult to emerge.”