ike a movie monster that refuses to die, tuberculosis is making a comeback. Scientists thought they had brought the disease under control with antibiotics in the 1950s and '60s. But since then, the tuberculosis-causing bacterium has evolved into drug-resistant strains, so cases are soaring.
Medicine is poised for a counterattack, however. Working with colleagues in France, scientists at London's Hammersmith Hospital have figured out how the tuberculosis bacterium evades drugs. The microbe's secret, the researchers reported in the Aug. 13 issue of Nature, is a single inoperative gene. This gene normally activates an enzyme that alters an antibiotic, changing it from harmless to deadly. Without the enzyme, the drug remains harmless.
The gene sleuthing opens the door for new drugs. One solution is simply duplicating the enzyme's effect by administering a converted form of the antibiotic rather than the original drug. Another is using the new information to figure out how the enzyme-altered chemicals actually kill microbes, then designing drugs that attack the same targets. The new discovery, concludes public health expert Dr. Barry R. Bloom of the Albert Einstein College of Medicine, "offers hope that molecular genetics may be one way to tackle the emerging problem of drug-resistant tuberculosis."