We usually write about health policy, not microbes and science, but sometimes they intersect. MRSA—as the stubborn pathogen methicillin-resistant Staphylococcus aureus is known—is a case in point. Hospitals are debating how to control MRSA, states are debating what policies or mandates will best spur progress, and insurers are increasingly saying that they regard hospital-acquired MRSA infections as an avoidable medical error—and they won't reimburse hospitals for the extra costs of treating it. So we asked Maryn McKenna, a health journalist and author of a book on the CDC and the forthcoming book SUPERBUG: The Rise of Drug-Resistant Staph and the Danger of a World Without Antibiotics to guest blog and catch us up.

Stopping the spread of the stubborn pathogen methicillin-resistant Staphylococcus aureus—MRSA, for short—is one of the most contentious topics in infectious disease policy right now. A small sample of the, umm, highly divergent views on the subject recently filled up the letters and pages of the Journal of the American Medical Association.

(Simple background review: MRSA is a subtype of an extremely common bacterium that, over 40+ years, has become resistant to a wide array of antibiotics used against it. From the late 1960s to the late 1990s, it was primarily a problem within hospitals, where it caused ferocious infections in vulnerable patients. In the 1990s, a community strain arose separately, with fewer resistance factors but greater virulence and an enhanced ability to spread among the apparently healthy. That's the strain responsible for widely reported sudden deaths of children from pneumonia and bone infections.)

Community-associated MRSA has grabbed the public's attention over the past year, but hospital-acquired MRSA remains a huge problem—so much so that the Center for Medicare and Medicaid Services has proposed treating it as a medical error and declining to reimburse hospitals for the extra care that must be given to a patient when it occurs.

Within health care, there is vociferous debate over how to control MRSA in hospitals. Because MRSA can live on the skin, nostrils and other body sites for a long period of time before causing an infection—either in the person colonized by the bug or in someone else who acquired it from the colonized person—many hospitals espouse a program of checking new patients who are most likely to be carriers, including patients in high-risk units such as ICUs, new admits from long-term care facilities (i.e. nursing homes), and people who have had MRSA infections in the past.

But a small set of institutions are pursuing a more aggressive program, variously called "active surveillance and testing," "universal screening" or "search and destroy," that checks every inpatient for MRSA colonization and confines them to isolation until the bug has cleared.

"Search and destroy" was the topic of an important JAMA paper and editorial last March that decided the effort wasn't worthwhile. (A simultaneously published paper in the Annals of Internal Medicine completely disagreed.) The five letters in the recent JAMA tear the topic apart, examining definitions, methodology, cost-effectiveness, adherence to infection control and more. The most intriguing suggests that "search and destroy" contains a hidden agenda: that if hospitals can demonstrate patients were carrying MRSA on admission, they may be able to make a case for any subsequent infections not being their fault—and escape the lowered reimbursement rates that CMS proposes.