MRSA infection rate higher than earlier thought

As data on the prevalence of methicillin-resistant Staphylococcus aureus in the community and in hospitals continue to pile up, more hospitals are taking an aggressive approach to preventing the superbug's spread.

A May 29 Archives of Internal Medicine study found that community-acquired MRSA increased sevenfold among low-income Chicagoans in the last five years, for example. And an Assn. for Professionals in Infection Control & Epidemiology study released last month reported that 34 of every 1,000 hospital inpatients are infected with MRSA.

That rate is 8.6 times higher than a Centers for Disease Control and Prevention study that examined 1999-2000 hospital discharge data and tallied more than 125,000 MRSA infections annually. The APIC figure is the result of an October 2006 snapshot survey of infection-control professionals at 21% of U.S. hospitals.

"This is a real wake-up call, particularly for administrative and clinical leaders," said APIC CEO Kathy L. Warye. "We don't live in a world of unlimited resources, but more needs to be done. This study shows that infection control is really important, and MRSA prevention is at the top of the list."

A number of hospitals are already taking action. The U.S. Dept. of Veterans Affairs announced in May that it would expand systemwide an MRSA-reduction initiative successfully piloted at the VA Pittsburgh Healthcare System. Like most similar efforts, the VA program tests high-risk patients to identify and isolate those with MRSA. The initiative also emphasizes hand hygiene and infection control.

All new patients are tested for MRSA upon admission to Evanston Northwestern Healthcare, outside Chicago. The program costs $600,000 to $1 million each year, epidemiologist Ari Robiscek, MD, told USA Today. However, efforts have cut the MRSA infection rate in half, to 50 cases annually. Most hospitals have engaged in more limited screening, testing only high-risk patients, such as those who are in the intensive care unit, are coming from long-term care, or have been admitted to a health care facility in the previous year.

A guide that the CDC's Healthcare Infection Control Practices Advisory Committee published last year calls for a two-tiered approach. First, hospitals implement infection-control practices such as hand hygiene, barrier precautions and correct use of antimicrobials. If these changes are not reducing the infection rate, hospitals should move toward screening high-risk patient populations.

"Every hospital needs to make this a priority," said John A. Jernigan, MD, a CDC medical epidemiologist. "This needs financial and human-resource commitment from hospital leadership to make it happen."

Weighing the costs and benefits of an active surveillance program are tricky, said Dr. Jernigan. While the Netherlands and Denmark have succeeded in virtually eradicating MRSA using active surveillance, they also successfully implemented the other, cheaper infection-control practices the CDC recommends as step one.

The Consumers Union has lobbied state lawmakers to require hospitals to screen high-risk patients for MRSA, and while seven states have considered such legislation, none has yet passed in that form.

A provision in Minnesota's omnibus budget bill calls for the state health department to consider requiring MRSA screening, though it is unlikely to be hospitalwide, according to a Minnesota Hospital Assn. spokeswoman.

Donald Goldmann, MD, senior vice president at the Institute for Healthcare Improvement, said while the organization's 5 Million Lives Campaign recommends that participating hospitals screen high-risk patients for MRSA, the evidence is not strong enough to justify regulation.

"I don't think legislatures should micromanage when the science is incomplete," Dr. Goldmann said.

So far, nearly 1,500 hospitals have committed to implementing the IHI campaign's MRSA-reduction interventions and an estimated 4,000 health professionals listened in on an IHI conference call about MRSA last month.