directly inhibits the growth of the bacteria in guinea pigs -- a surprising result since the drug has been widely used as an antibiotic for over 40 years but has not been considered effective against TB. They also studied HIV-infected TB patients in South Africa to look for further evidence that MMP-1 is responsible for destroying lung tissue. They found that concentrations of this enzyme were suppressed in people with advanced HIV infection, explaining for the first time why such patients do not suffer from such extensive lung destruction when they get TB. "TB treatment has remained unchanged for over 30 years, and totally drug-resistant strains are emerging, so there's a real need for new drugs." s aid Dr Paul Elkington , from the Department of Medicine at Imperial College London, who led the study. "Because doxycycline is cheap, safe and widely available throughout the developing world, it may be a useful new treatment for TB that can be used in resource-poor settings. Our results so far are promising but we have only looked at human cells and animal models. We hope to carry out a clinical trial soon to test whether doxycycline is effective at combating TB in patients."