Old antibiotic could be a new weapon to fight tuberculosis

Old antibiotic could be a new weapon to fight TB

(Medical Xpress) -- A cheap and safe antibiotic that is widely available in the developing world might have a new use as a tuberculosis (TB) treatment, according to new research.

TB kills almost 2 million people a year worldwide, and is increasingly becoming resistant to the antibiotics used to treat it, but there are few new drugs in the pipeline. Doxycycline was introduced in 1967 and is used to treat a wide range of bacterial infections, but until now has not been recognized as effective against TB. The new study, published in the American Journal of Respiratory and , suggests that doxycycline might stop the bacteria from growing and also prevent the disease from damaging the lungs.

Last year, researchers at Imperial College London discovered that TB increases the production of an enzyme called MMP-1, and that this enzyme is responsible for destroying .

Now they have found that doxycycline suppresses the production of the tissue-destroying enzyme in TB-infected . They also found that doxycycline directly inhibits the growth of the bacteria in – 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.

has remained unchanged for over 30 years, and totally drug-resistant strains are emerging, so there’s a real need for .” said 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.”

The researchers found further evidence for the antibiotic effect of doxycycline in TB bacteria grown in a liquid broth. The higher the concentration of , the lower the rate of bacterial growth.

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.

The Imperial team worked with collaborators at the University of Cape Town and the Health Protection Agency (HPA) at Porton Down. The research was funded by the National Institute for Health Research (NIHR), the Wellcome Trust, the NIHR Biomedical Research Centre at Imperial, and the HPA.

More information: NF Walker et al. ‘Doxycycline and HIV infection suppress tuberculosis-induced matrix metalloproteinases.’ American Journal of Respiratory and Critical Care Medicine, published online 16 February 2012. , doi:10.1164/rccm.201110-1769OC

Related Stories

HIV/AIDS linked to drug resistant TB

Nov 16, 2006

U.S. scientists say a highly drug-resistant form of tuberculosis has been linked to HIV/AIDS in a study conducted in rural South Africa.

Recommended for you

WHO: Ebola vaccine trials in W. Africa in January

7 hours ago

Tens of thousands of doses of experimental Ebola vaccines could be available for "real-world" testing in West Africa as soon as January as long as they are deemed safe, a top World Health Organization official ...

Ebola cases rise sharply in western Sierra Leone

7 hours ago

After emerging months ago in eastern Sierra Leone, Ebola is now hitting the western edges of the country where the capital is located with dozens of people falling sick each day, the government said Tuesday. So many people ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

ironjustice
not rated yet Feb 20, 2012
Bacteria use iron to survive and proliferate. Increased iron is known to increase infection. Many of the antibiotics work on that principle , removing iron.

"Doxycycline possesses iron-chelating activity"