A new approach to designing antibiotics could give doctors the upper hand in their battle against harmful germs and avert the looming medical crisis posed by the spread of drug-resistant bacteria.
Hopefully, one day it will save lots of lives, said Reza Ghadiri, a chemist at the Scripps Research Institute in La Jolla, Calif. He and 10 colleagues described their work in Thursdays issue of the journal Nature.
Over the past decade, Ghadiri and other researchers in his laboratory have developed self-assembling nanotubes, disk-shaped amino acid molecules that stack themselves into tubes whenever they encounter the proper chemical environment. That environment varies depending on which amino acids the researchers select.
The trick in turning such molecules into antibiotics, Ghadiri explained, is to select a set of disks that assemble themselves inside the membrane surrounding a bacterial cell, punching a hole in the membrane and exposing the microbe to the outside world.
With tiny tubes springing up inside its membrane, a bacterium becomes leaky as a sieve, and dies as its contents spill out and the bodily fluids of its host rush in.
Its a great concept. Its really exciting, said Robert Hancock, a microbiologist at the University of British Columbia in Vancouver, Canada.
Ghadiri and his colleagues were delighted to see some of their molecules working in the test tube, killing antibiotic-resistant Staphylococcus aureus and E. coli while sparing human red blood cells.
But they were even more impressed by what their best concoctions could do for mice infected with the antibiotic-resistant staph bacterium. In experiments performed last year, high enough doses of three different self-assembling molecules could cure what would have been lethal staph infections.
Nevertheless, Ghadiri cautioned that much more development is needed before self-assembling antibiotics become available at the pharmacy. Therapies that look promising in animals frequently fizzle in humans.
Extensive testing in animals and humans often brings up unforeseen problems, Tomas Ganz, a professor of medicine at the University of California at Los Angeles, wrote in an accompanying commentary. But, in the face of increasing microbial resistance to existing antibiotics, every new lead is welcome news.
Copyright © 2001, Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.