A Killer Called Staph
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But since the 1970s, a strict no-tolerance policy has driven down infection rates in much of Europe—particularly in the Netherlands, Iceland, Norway, Denmark and Sweden—to extremely low levels. In Dutch hospitals, patients are routinely tested to see whether they’re harboring MRSA strains. Even those who merely have transient bacteria in their nasal passages are isolated in single rooms, and visiting family members must be gowned and masked. Meanwhile, physicians and others who come in contact with affected patients are constantly monitored through nasal swabs to make sure they’re not carrying the bacteria. Hospital workers in these northern European countries wash their hands often and use alcohol-based sanitizers, which are even more effective than soap and water—and easier on the hands. Floors and other surfaces are frequently disinfected.
In the United States, the PRHI has also begun to make measurable headway against MRSA. Inspired by former U.S. Treasury Secretary Paul O’Neill’s success at improving worker safety when he was CEO of Alcoa, PRHI has adopted principles of the Toyota Production System in declaring a systematic war on MRSA. Like workers in Toyota plants, all employees in participating Pittsburgh-area hospitals—from physicians and administrators to aides and the cleaning crew—have been given the authority to take action whenever they spot a problem. And just as Toyota produces virtually defect-free vehicles, PRHI hospitals have sharply cut infection rates among patients.
According to Richard P. Shannon, chairman of the department of medicine at Allegheny General Hospital and an executive committee member of PRHI, 236 patients had documented MRSA infections during the three years preceding the MRSA initiative. Those infections cost the hospital $3.2 million, or almost $14,000 per patient. Patients with MRSA infections spent an average of 31 days in the hospital, and 49% were readmitted at least once for MRSA-related complications. Thirty-eight patients died.
At Allegheny, patients are now swabbed nasally when they are admitted to intensive-care units to make sure they aren’t harboring MRSA. “About 8% come in with MRSA,” says Shannon. “We never would have known that before.” As in northern Europe, infected patients, four out of five of whom have been hospitalized previously, are isolated and treated; health-care workers and visitors must wear disposable gowns, gloves and masks; and anyone walking into these patients’ rooms must use a hand sanitizer. Shannon and his team rely on a long list of little things that, taken together, can be remarkably effective. “There is no magic bullet, no vaccine,” he says. “This is not about technology; it’s about process.”
It is also about getting physicians and other hospital personnel to take responsibility for halting the spread of MRSA—and in most U.S. hospitals, that hasn’t happened. Part of the problem, according to Perreiah, is that most doctors seem to think that the main culprit is overprescription of antibiotics. But if that were indeed the case, with new strains of MRSA constantly developing to evade attack by overabundant antibiotics, researchers would expect to find a great number of clones—distinct genetic lines—with diverse ancestry. Yet 70% of MRSA strains are descendants of just two clones, one of which originated in Denmark during the late 1950s.
The resistance of S. aureus to some important drugs—the so-called beta-lactams—is based on a gene called mecA, part of a cassette of DNA that S. aureus acquired from some unknown bacterial donor. The mecA gene itself probably originated in S. sciuri, a germ that lives on the skin of many animals. Though it’s not known where the cassette came from or how it entered S. aureus, it may have been through conjugation—a direct exchange of bacterial DNA through physical contact between a donor cell and S. aureus—or by some other means, such as with the help of a bacterial virus.
