Last update - 00:00 11/01/2007
Weizmann Institute research promises antibiotics revolution
By Ofri Ilani, Haaretz Correspondent
Scientists at the Weizmann Institute of Science have developed novel antibiotics that are more effective than conventional drugs in fighting bacteria. The substance they developed melts the germ's cell surface rapidly, preventing it from producing a new generation of bugs that have adapted to the medicine. But it may be a decade before the discovery is put into use.
In recent decades scientists have warned of bacteria's increasing resistance to most kinds of antibiotics.
Few scientific discoveries have had as profound an effect on humanity as the discovery of penicillin 81 years ago. In the world before antibiotics, the infection of a small wound was potentially fatal, and pneumonia killed millions of people. But at the present rate of germs becoming immune to antibiotics, current medications may become ineffective within 20 years. The implications are disastrous. Medicine could be helpless in conquering illnesses considered relatively easy to cure today.
The reason for growing bacterial resistance is that existing antibiotic strains attack only certain "targets" in the germ, leaving active remnants. The next generation of germs receives the information from the injured ones and mutates, rendering the antibiotic ineffective. The main damage is caused by the wrong use of antibiotics. If the entire dose is not consumed, germs remain in the body and quickly learn how to become resistant to the substance.
Now Weizmann Institute scientists, headed by Professor Yehiel Shai, have designed a more powerful antibiotic. The system that Shai and Ph.D. students Arik Makovitzky and Dorit Avrahami of the Biological Chemistry Department have developed causes massive destruction of germs and completely melts their cell surface. The germ is destroyed too fast to enable it to study the medicine's characteristics and thus it cannot transfer information to the next generation.
Shai's team succeeded in combining the properties of a natural antibiotic produced by all organisms. Because these antimicrobial peptides (AMPs) are positively charged, they are attracted to the bacteria's negatively charged surface like a magnet, where they can then destroy them. "These methods have worked for natural organisms for millions of years, so they should be effective for a very long time," Shai says.
As reported in the Proceedings of the National Academy of Sciences (PNAS), the team succeeded in combining the properties of AMPs with lipopeptides, resulting in a synthetic lipopeptide that has both a positive charge and the soap-like ability to dissolve oils.
"It's a sort of sophisticated soap, which melts the fatty part of the germ cover, compared to ordinary antibiotics, which penetrate the cell and then paralyze specific systems," says Shai.
Shai says the technology he and his team have developed is still in a preliminary stage and could take 10 years until it is put into use.
"The graver the problem of germs becoming immune becomes, the more resources I assume they'll invest in it," he says.