(Reuters) - U.S. health regulators have approved a new Johnson & Johnson drug for patients with tuberculosis who do not respond to other treatments, the company said. The drug is the first in 40 years to tackle the disease using a new mechanism of action, according to J&J. The drug blocks an energy-producing enzyme that tuberculosis bacteria need to survive. The U.S. Food and Drug Administration approved the drug, chemically known as bedaquiline and called Sirturo, on Monday following a positive review by an advisory panel last month. ...