Published On Jan 28, 2015
A Killer Still on the Loose
MRSA infections are down by more than half, and new treatments are on the way. But the pathogen still takes a deadly toll.
There is good news and bad news in the battle between U.S. hospitals and deadly, virulent, drug-resistant staph, or MRSA—a leading cause of life-threatening hospital-acquired infections in the country. MRSA bacteria (methicillin-resistant Staphylococcus aureus,) travel easily, hitching rides on nurses, doctors, aides, even visitors—and, as Proto discovered in 2006 (“A Killer Called Staph,”) many hospitals were slow to halt its spread. Some strains also appeared to be resistant to common hospital disinfectants, and a few also to the drug most commonly used to treat MRSA infections, vancomycin.
First, the good news: Rates of hospital-acquired MRSA have fallen dramatically, declining an estimated 54% nationwide between 2005 and 2011, according to a CDC study published in the Journal of the American Medical Association Internal Medicine. That represents 30,800 fewer severe drug-resistant staph infections, such as bloodstream infections, pneumonia and surgical site infections, and 9,000 fewer deaths in hospital patients in 2011 versus 2005.
Though the CDC said the cause of the overall decline is uncertain, it speculated that better hospital-based infection prevention is one possibility, as well as “improved early management of noninvasive infections,” and “changes in the virulence of the circulating strains.” Over the past decade, many major U.S. hospitals have doggedly ramped up doctor and nurse compliance with the CDC’s hand hygiene and contact precaution recommendations: applying hand disinfectant before and after all patient contact, using disposable gloves, gowns and stethoscopes, as well as “patient cohorting,” or protocols that prevent patients who have tested positive with MRSA from rooming together with patients who haven’t. Compliant hospitals have documented declines in MRSA infections.
More good news: the U.S. Food and Drug Administration approved three new antibiotics that can treat MRSA infections just this past summer—after a long period during which there were no new treatments. The new drugs are either designed to treat strains of MRSA that are not susceptible to vancomycin, or they are more potent, and therefore have fewer side effects or require fewer doses, and so can be administered to patients who aren’t in the hospital, according to David Hooper, chief of the Infection Control Unit at Massachusetts General Hospital in Boston. Another antibiotic, linezolid, is going off patent next year and will become more accessible as an alternative to vancomycin.
Now for the bad news: In 2012, MRSA still afflicted an estimated 75,000 hospital patients and killed some 9,600 people in the U.S., according to CDC data. Some scientists believe it will take a vaccine to eliminate MRSA entirely, but developing one has proven very difficult and is progressing slowly. “The bottom line is that we do not know what to put into the vaccine,” says Robert Daum, director of the University of Chicago MRSA Research Center, who has worked on vaccine research for several years. “Staph is too smart. It’s been around too long. It’s a perfectly adapted human pathogen.”