MRSA Cases Dropping in Hospital ICUs

TUESDAY Feb. 17, 2009 -- Blood infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have dropped significantly in hospital intensive care units, researchers from the U.S. Centers for Disease Control and Prevention report.

MRSA, a type of staph bacteria that's resistant to certain antibiotics, can cause severe infections in people in hospitals and other health-care facilities. It can also cause serious skin infections in healthy people who haven't recently been hospitalized.

The tough-to-treat blood infections have caused the most concern, but the new CDC numbers suggest that hospital prevention efforts may be turning the tide against MRSA.

"The risk of bloodstream infections caused by MRSA that are associated with the use of central line catheters has dramatically declined by 50 to 70 percent since 2001, in all types of adult ICUs," said lead researcher Dr. Deron C. Burton, associate director of CDC's Health Equity National Center for Health Marketing.

A central line is a catheter inserted into a large blood vessel. The tip of the catheter is typically close to the heart or in the aorta or jugular vein.

The drop in these infections is largely due to better procedures that have improved the safety of catheters, Burton said. "There has been improvement in the sterility of how they are inserted and how they are cared for while they are in the patient," he explained.

The report is published in the Feb. 18 issue of the Journal of the American Medical Association.

For the study, Burton's group collected data from hospitals reporting on MRSA infections to the CDC. Specifically, the researchers looked at ICU-based MRSA infections associated with central line catheters from 1997 to 2007.

During that period, 1,684 ICUs reported almost 33,600 central line bloodstream infections. Of these, 7.4 percent were MRSA and 4.7 percent were methicillin-susceptible Staphylococcus aureus (MSSA), meaning the infection could be treated with the antibiotic.

Although the percent of infections attributed to MRSA increased by nearly 26 percent over the period, the actual number of MRSA infections dropped by close to 50 percent, the researchers noted. This overall drop took place after 2001 and continued through 2007, the researchers found.

The decline in MRSA infections was seen in all types of ICUs. For example, infections dropped 51.5 percent in medical-surgical ICUs and by more than 69 percent in surgical ICUs. The number of MRSA infections in pediatric ICUs remained stable, although MRSA infections in these ICUs was already low to begin with, the researchers noted.

Infections from MRSA were not the only ones to decline, Burton said. "We looked at bloodstream infections being caused by any pathogen, not just MRSA. When we looked at all causes of these central line bloodstream infections lumped together, we saw declines of roughly 40 to 50 percent in the risk of these infections," he said.

"Hospitals should be encouraged by these results," Burton said. "Their efforts should be continued and expanded."

The findings are also great news for patients, Burton added. "Central lines have become safer in recent years, at least with the risk of causing bloodstream infections," he said.

Dr. Pascal James Imperato, dean and distinguished service professor of the graduate program in public health at SUNY Downstate Medical Center in New York City, said he was heartened by the findings.

"MRSA central line-associated bloodstream infections were once common," he noted. "The present study is of great significance because of its size and decade-long comparisons. The dramatic declines in bloodstream infections due to MRSA, and associated with central lines in adult patients in intensive care units, reflect the implementation over the past several years of a variety of very effective preventive barrier techniques."

Important among these improvements are changes in central line insertion techniques and the maintenance of such lines. The implementation of techniques in hospitals to prevent the transmission of MRSA between patients has also been invaluable, Imperato added.

"The results of this study demonstrate that when appropriate prevention techniques are scrupulously implemented in the health-care setting, the incidence of MRSA and other forms of infection can be dramatically reduced," he said. "Such preventive measures, now being more aggressively applied in most health-care settings should, hopefully, greatly reduce the incidence of all forms of MRSA infections."

Dr. Marc Siegel, an associate professor of medicine at New York University School of Medicine in New York City, agreed. But he said that hospital infection prevention efforts also need to cast a wider net.

"We have been obsessing over MRSA at the risk of losing site of the larger picture, which is improving our surveillance and eradication of all pathogenic organisms in hospitals," Siegel said. "The point this paper is making is that the overall number of infections is going down, including MRSA."

More information

For more information on MRSA, visit the U.S. Centers for Disease Control and Prevention.

Posted: February 2009


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