Testing for Tuberculosis

Doctors think that one third of the world's population have been exposed to the bacterial infection TB, or tuberculosis. It can damage any tissue in the body, infect the skeleton and joints, and even cause meningitis, but most people develop chest disease and a cough, which is how it chiefly spreads. A major problem with controlling the infection is that the Mycobacterium tuberculosis bacteria can be very hard to culture in a laboratory, and they grow extremely slowly, which holds up diagnosis and also makes it tricky to tell quickly whether someone is actually responding to the treatment they're receiving. Now microbiologists at St Andrews University, working with the charity Life Arc, have come up with a genetic test that looks for a very short-lived form of genetic material called ribosomal RNA that is specific to the TB bacteria. Their aim is to turn what's currently a lab research tool into a very quick and cheap test for use in remote and poor settings. Stephen Gillespie