June 25, 2007 - The prevalence of the drug-resistant staph MRSA in the nation's hospitals is as much as 11 times greater than previous estimates suggest, according to findings from the most comprehensive study of the infection ever done.
For every 1,000 patients treated in U.S. hospitals, 46 cases of methicillin-resistant Staphylococcus aureus (MRSA) now occur, researchers concluded.
The finding was based on "snapshot" surveys of infection control workers representing 21% of the health care facilities in the United States, conducted by the group Association for Professionals in Infection Control and Epidemiology (APIC).
The study was also the first to include both active MRSA infection and patients who were carriers of the bacteria (not sickened by infection, but were able to transmit it to others).
Infection control specialist William Jarvis, MD, tells WebMD that the findings should serve as a wake-up call for those running the nation's hospitals, nursing homes, and other in-patient health care centers.
"We know what to do," he says. "This problem is larger than we thought, and the resources need to be made available to appropriately address it."
MRSA 'Super Bug'
First reported in U.S. hospitals in the late 1970s, MRSA is now by far the most common hospital-acquired staph infection in this country and throughout the world.
Known as a super bug because it is resistant to so many antibiotics, MRSA is seen most often in patients who have undergone invasive medical procedures or who have weakened immune systems.
While it is clear that MRSA is a growing problem in the nation's hospitals and other health care facilities, little research has been done to determine the exact magnitude of the problem at a national level.
In an effort to address this, APIC polled its members working in infection control at hospitals and other health care centers in all 50 states.
Participants were asked to provide a one-day 'snapshot' of their facility's MRSA burden, including patients who were either infected or colonized, meaning they had no symptoms from the MRSA but were able to transmit MRSA to others.
The survey responses indicated that for every 1,000 patients treated in hospital or other in-patient health care settings, 34 are infected and 12 are colonized with MRSA.
Seventy-five percent of cases were identified within 48 hours of hospital admission, meaning these patients probably acquired the infection during a previous hospital stay or within the community.
Most MRSA is transmitted in hospitals and other health care facilities, but there is growing concern about community-acquired drug-resistant staph infections.
At first glance, the latest findings suggest a high prevalence of community-acquired MRSA, but Jarvis says the clinical presentation of the cases indicates that most infections were acquired during previous hospital stays.
Hospital-acquired MRSA can manifest as serious and potentially life-threatening bloodstream infections, surgical site infections, or pneumonia in patients who may have weakened immune systems.
Community-acquired MRSA generally presents as a skin infection and is commonly seen in people who are otherwise healthy.
"The extent of the problem of health-care associated infection is much larger than that of community-acquired infection, but our data suggest that the both are increasing," Jarvis says.
While health care facilities were generally quick to employ recommended practices to prevent the spread of MRSA once the organism had been identified, the survey indicated that delays in diagnosing patients with the drug-resistant staph infection or colonization are placing health workers and other patients at unnecessary risk.
"Some health care facilities are aggressively addressing MRSA, but the scope of this public health threat demands commitment and participation from every facility, at all levels," says APIC President Denise Murphy, RN.
Last fall, the CDC issued recommendations for managing MRSA and other multidrug-resistant organisms in hospitals, stressing the judicious use of antibiotics, frequent hand washing by all medical personnel and support staff, and surveillance.
CDC medical epidemiologist John Jernigan, MD, says it is clear that MRSA can be controlled when proper procedures are followed.
"MRSA is a hugely important problem in U.S. health care facilities, and more needs to be done to prevent it," he says. "Every step of the way these facilities should be closely monitoring MRSA rates, and adjusting their approach to controlling the spread of the organism if these rates aren't coming down.