A cure for Cholera. The Australian.2005

Uncertain date.

John Stapleton
AUSTRALIAN scientists believe they may have discovered a cure for life-threatening bacterial diseases such as cholera in an unusual red seaweed found only off the east coast of Australia.

The compounds, known as furanones, do not kill microbes, as with traditional antibiotics, but simply ``jam'' their ability to communicate and colonise.

Initial laboratory tests at the University of NSW announced yesterday show that furanones stop cholera bacteria from ``switching on''. Disease-causing bacteria rely on what scientists call ``quorum sensing'' to determine when they have invaded in sufficient numbers to overwhelm the body's immune system.

One of the scientists involved, Dr Diane McDougald of UNSW's Department of Biotechnology, said it had only discovered in the past decade that bacteria use a chemical language that allows them to sense whether there are enough of them present to overwhelm the host immune system.

``Only when there is a large enough number of bacterial cells present, do they then start to exhibit virulence traits,'' she said. ``Because furanones don't kill bacteria, there is no selection pressure for them to develop resistance. In  millions of years of evolution no natural resistance has been developed by bacteria to these furanones. These are the first antimicrobials of their type that have been shown to be effective. Many bacteria caused diseases are becoming resistant to antibiotics and are becoming harder and harder to treat.''

Furanones may also offer a cure for antiobiotic resistant super-germs such as golden staph, as well as tuberculosis and food poisoning. The chemical is already being commercially developed to create extended wear contact lenses which do not cause eye infections.

The discovery of furanones has its origins in a conversation between micro-biologists and marine ecologists at the University of NSW over the peculiar properties of the seaweed Delisea pulcrha. Unlike most other seaweeds the small red algae produces a chemical which prevents other organisms attaching to it, giving it a pristine appearance.

A company, Biosignal Ltd, formed in 1999 to market furanones and other so-called ``smart molecules'' developed in Australia, argue that furanones may eventually be used on everything from ship hulls to human teeth. While human trials are yet to begin, news of the early positive results of tests on cholera germs provided to the Australian Stock Exchange sent the share price surging 17% yesterday before it settled back in a day of generally poor results. Human tests on the anti-bacterial contact lenses, with a potential worldwide annual market of more than $1 billion, begin in the new year.