This article is more than 5 years old. Information may no longer be current.

CA-MRSA genotypes linked to an increasing number of infections in the ICU

Add topic to email alerts

Receive an email when new articles are posted on

Please provide your email address to receive an email when new articles are posted on .

Subscribe

Added to email alerts

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

Back to Healio

We were unable to process your request. Please try again later. If you continue to have this issue please contact customerservice@slackinc.com.

Back to Healio

Among patients admitted to intensive care units, older patients and patients who were previously hospitalized were significantly less likely to be colonized with community-acquired methicillin-resistant Staphylococcus aureus, according to results from a multi-center study conducted in the United States.

These findings were presented at the 2009 meeting of the Society for Healthcare Epidemiology of America.

Data from 5,512 adult ICU visits were included in the STAR-ICU trial. Researchers selected 210 of 626 MRSA isolates for molecular typing. All isolates were collected from the nares region. Analysis demonstrated that 14% of patients were colonized with CA-MRSA genotypes USA300, USA400 or USA1000.

Univariate and multivariate comparisons between patients with hospital-acquired MRSA and those with CA-MRSA revealed that patients with community-acquired strains were less likely to have been hospitalized in the 12 months prior to infection (95% CI; 0.21-0.73) and to be older (prevalence ratio=0.97 per year, 95% CI; 0.95-0.98).

Henry Blumberg, MD, of the Division of Infectious Diseases at the Emory University School of Medicine and the Epidemiology Department at Grady Memorial Hospital in Atlanta, presented these results. “These findings suggest that the predominant site of CA-MRSA acquisition remains the community,” he said. – by Rob Volansky

For more information:

• Blumberg H. #48. Presented at: Annual Meeting of the Society for Healthcare Epidemiology of America; March 19-22, 2009; San Diego.

Hospitalized patients, particularly those with long hospital stays, may result in MRSA or MSSA colonization. Hospital-acquired MRSA (HA-MRSA) colonization is often transient and usually involves the nares/skin. Most patients who are colonized with HA-MRSA strains when discharged and who are no longer receiving antimicrobial therapy frequently spontaneously terminate MRSA carriage over time. However, some become chronic carriers.

MSSA biologically competes with MRSA for the same ecological niche in the nares/skin of hospitalized patients. Colonization with MSSA prevents simultaneous colonization with MRSA. This study describes community-acquired MRSA colonization in previously hospitalized ICU patients. Patients who were colonized with CA-MRSA in the community who are admitted to the ICU may introduce CA-MRSA into the hospital. However, only 14% of elderly patients admitted to ICUs were colonized with CA-MRSA. Fortunately, the reservoir for CA-MRSA remains in the community.

– Burke A. Cunha, MD

Infectious Disease News Editorial Board member