A New Age | Unnatural Laboratories

Enlisting New Fighters
Very few antibiotics have been developed over the last five decades. While medicine's arsenal of antibiotics has changed very little, new infectious diseases are emerging. Even more alarming, some microbes responsible for diseases we thought long conquered are now showing resistance to our existing antibiotics. As antibiotics lose their ability to control these diseases, scientists are busily looking for new, more effective drugs.

The best source of antibiotics may be nature. Natural defenses found in plants, animals, and microbes are rich sources of antimicrobial agents. However, the difficult part of cultivating natural antibiotics is that less than one percent of microbes can be grown in the laboratory. Most live in complex ecosystems that are difficult to replicate in the lab.

Dr. Julian Davies, a microbiology professor at the University of British Columbia, is developing methods to grow these elusive microbes using "surrogate" microbial hosts that can be grown in the lab. These surrogates readily take up the other microbe's DNA, incorporating with its new defenses that become part of the surrogate's own genetic code. This isn't a new technique -- microbes do it all the time.

Tiny fragments of DNA called plasmids are commonly transferred between microbes. A single plasmid can pass on many different genetic traits, including antibiotic resistance. Exploiting this natural ability, researchers can inject genetic information from one microbe into another.

To develop antibiotics taken from natural sources, Dr. Davies founded Terragen, a commercial biotechnology lab located on campus. Davies and other researchers from his lab routinely collect samples from different natural environments and take them back to the lab. After they are cultivated, they can be tested for beneficial antibiotic ability. Terragen may have already discovered its first antibiotic. However, it's a long and difficult process to get a new antibiotic to the pharmacy shelf.

The Wonders of Microbes, on the MicrobeWorld Web site, has more information on antibiotics.

A New Age | Unnatural Laboratories

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