Tough-to-treat staph infections that patients can pick up while in the hospital fell by nearly 30 percent in the last decade, according to U.S. health officials. …Staph strains resistant to the antibiotic methicillin can only be treated with one other antibiotic, and the worry is they will become resistant to that one too. MRSA infections are often picked up while patients are in the hospital being treated for something else, or in other healthcare settings, such as dialysis centers, that people with chronic illnesses visit regularly. …While the new study cannot explain why infection rates are dropping, [lead researcher Dr. Raymund] Dantes said it’s likely attributable, in part, to hospital efforts to reduce the spread of infections. “It’s also possible that there has been evolution of these strains and they’re less invasive,” Dr. Franklin Lowy, from the Columbia University College of Physicians and Surgeons in New York who wrote an editorial accompanying the new study in JAMA Internal Medicine, said.