Fungal link offers TB hope

TB bacterium and fungi have genetic similarities

By the BBC's Richard Black

Drugs used to treat fungal infections might also prove useful against tuberculosis, according to scientists in Britain.

They have found a genetic similarity between the TB bacterium and fungi, which they believe makes the bacterium vulnerable to these drugs.

TB is on the rise in Africa

Tuberculosis kills two million people each year, a figure that is rapidly rising in parts of the world where Aids is widespread.

Drugs are available, but they are gradually becoming less effective as the bacterium becomes resistant to them.

So there is an urgent need for new lines of treatment.

Now, researchers at the University of Wales in Aberystwyth say they have found one.

Genome breakthrough

The key was an international research project which sequenced the TB genome - work conducted at the Wellcome Trust's Sanger Centre, Cambridge, UK, and at the Institut Pasteur, Paris, France.

When the Aberystwyth researchers examined the sequence, they discovered that TB contains a gene that is also found in the kinds of fungi which infect humans.

There are already anti-fungal drugs called azoles, which work by blocking this gene.

The researchers tried giving these drugs to a close relative of TB in the laboratory, and found that they killed it.

Price problem

They are now starting experiments with TB itself.

If the drugs do work here, the researchers will have found a completely new way of attacking this tough bacterium.

And as azoles are already widely used, far fewer safety trials will be needed than with new drugs.

The problem area could be price - several of these drugs are still under patent, and according to the World Health Organisation, even those which are not are still priced too highly for the poorest parts of the world.