Antibiotic resistance is one of the biggest global health challenges. Our strongest antibiotics are ineffective as bacteria evolve and develop new defense mechanisms against these drugs. So, how quickly can bacteria develop resistance to antibiotics?
Although it depends on the type of bacteria and many other factors, “it can actually be instantaneous to a few days of evolution,” Mark Blaskovichmedicinal chemist and co-founder of the Superbug Solutions Center at the University of Queensland in Australia, told Live Science. “Selection pressure leading to new mutations capable of conferring resistance can occur in a single generation, or in a doubling time.”
Some bacteria, such as Escherichia colican divide or double every 20 minutes. Because they reproduce so quickly, they tend to pass on more genetic mutations each time they double in comparison and complex organisms, such as humans, whose cells divide about every 24 hours. That means that a mutation that helps bacteria avoid antibiotics can be passed on to their offspring. or other people at the time, Blaskovich said.
The possibility of antibiotic resistance also depends on the type of bacteria and the antibiotic. Most bacteria need to enter cells to thrive. As a result, gram-negative bacteria are pathogenic the outer membrane of a cellit tends to be more resistant than Gram-positive bacteria due to increased immunity.
In 2016, researchers from the Technion-Israel Institute of Technology and Harvard Medical School completed a table size chart. a petri dish with E. coli bacteria and the antibiotic trimethoprim, which normally kills bacteria that cause urinary tract infections. They divided a large petri dish into nine compartments, containing antibiotics in each compartment between zero and 1,000 times the lethal dose for E. coli.
Related: Harmful ‘superbugs’ are a growing threat, and antibiotics are unable to stop their rise. What can?
The scientists found that in just 11 days, the entire population had acquired genetic mutations that made it less resistant to the antibiotics tested in the experiment.
Watch First
But this is at the level of citizens, Blaskovich noted. With a study like this, “you miss the nuances of what’s going on inside individual cells,” he said.
Furthermore, when antibiotics fail in the clinic, it is often due to the growth of bacteria that already have resistance genes, as opposed to bacteria that develop new antibiotic mutations during treatment, Blaskovich said. he said. So, in real patients, it may take even less time for the bacteria population to become stronger than it did in petri dish experiments, he said.
Sometimes, a small number of bacteria can survive antibiotics than the rest of the population. These “extra” bacteria can grow better than the rest of the population.
There is four common methods Bacteria can become resistant to antibiotics: by changing their cell walls to prevent antibiotics from entering the cells, by pumping the antibiotics out of the cells, by changing the bacterial protein that the antibiotics bind to targeting, and by producing enzymes that inhibit antibiotics.
Each of these processes takes a different amount of time to evolve, Blaskovich said. For example, an antibiotic that binds to a bacterial target controlled by a single gene may induce a rapid genetic mutation, especially if the mutation does not interfere with its function. inside a living thing. On the other hand, if resistance to antibiotics requires mutations that inhibit essential bacterial activity, resistance can take a long time to develop.
Another way scientists and doctors overcome antibiotic resistance is by using a combination of drugs with different mechanisms of action. In this way, each antibiotic will have a limited impact on the evolution of a particular mechanism of resistance.
“Over the last 20 to 30 years, we’ve gotten a better understanding of the properties that allow antibiotics to get inside bacteria,” Blaskovich said. “The biggest roadblock, really, in antibiotic development is just the lack of people doing it.”
#quickly #antibiotic #resistance #evolve