The U.S. Food and Drug Administration has approved a new antibiotic that, in combination with two existing antibiotics, can tackle one of the most formidable and deadly treatment-resistant forms of the bacterium that causes tuberculosis. The new antibiotic, called pretomanid (PA-824), can work with the other drugs like a deadly cocktail—triggering the bacteria (Mycobacterium tuberculosis) to release nitric oxide. This can burst the bacteria's cell walls and poison the microorganisms.