Scientists Halt Bacteria’s Resistance to Antibiotics
Researchers have found a way to turn off the genes that make bacteria resistant to antibiotic drugs, a discovery that could help head off a major medical crisis in the treatment of infections.
Bacteria have been growing increasingly resistant to antibiotics. Many infections no longer respond well to drugs that once worked against them.
“This method could restore the full usefulness of today’s front-line antibiotics, thus bypassing the tremendous expense of developing new antibiotics,” said Nobel Prize laureate Sidney Altman, who led the Yale University team that made the discovery.
The team found a way to insert artificial genes into bacteria to make the germs highly sensitive to two widely used antibiotics: chloramphenicol and ampicillin.
Altman cautioned, however, that the technique has been demonstrated only in laboratory cultures and could take five more years of research before it is ready to test in humans.
“There is a big, big gap between doing something in the laboratory and making an effective therapeutic tool,” said Altman.
A report on the study is to be published in today’s edition of the journal Proceedings of the National Academy of Sciences.
“It’s exciting they’re able to essentially switch the resistance off. That’s the first time that’s happened,” said Dr. Stephen Heyse, who studies bacterial resistance at the National Institute of Allergy and Infectious Diseases.
But no one yet knows how to deliver the artificial genes into specific cells, meaning moving the discovery out of the test tube will be difficult at best, Heyse cautioned.
Even if the method could work in people, it’s not likely to end the problem of drug resistance, added Dr. Mitchell Cohen, bacteria resistance chief at the federal Centers for Disease Control and Prevention.
“Any time you do something that kills bacteria, you put selective pressure on those bacteria to change to get around it,” Cohen said. “This would be another approach to deal with resistance” but not a cure-all.
Antibiotic resistance has become a growing medical concern in recent years. For instance, the bacteria that causes meningitis once was routinely controlled with ampicillin, a commonly prescribed antibiotic. But now about 20% of such infections are resistant to ampicillin.
*
In the experiment, the Yale researchers made synthetic genes that shut down the bacteria’s ability to resist antibiotics. The genes were introduced into the bacteria using small packets of DNA called plasmids. The synthetic genes inside the bacteria started a process that leads to the formation of an enzyme that destroys a specific gene. Blocking the action of the targeted gene lowered the bacteria’s defenses against antibiotics.
The biggest problem is finding a way to deliver synthetic genes to specific cells, Altman said. The laboratory technique is unlikely to be used in humans, Altman said, and it could take at least five years of intensive research to find an improved method of gene delivery.
