554. The Predictive Value of Initial MRSA Screen in Subsequent MRSA Infection
Session: Poster Abstract Session: MRSA Surveillance and Infection Prevention
Friday, October 21, 2011
Room: Poster Hall B1
Background: MRSA remains a public health threat. Its emergence has triggered many screening programs to identify carriers. In January 2008, active surveillance for MRSA nasal colonization was instituted at Albert Einstein Medical Center using a polymerase chain reaction assay for the detection of the mecA gene. We studied the predictive value of the MRSA admission screen for the development of subsequent MRSA infection.

Methods: This is a retrospective study in our tertiary care medical center from February 1, 2008 to December 31, 2008. Data on admission MRSA screens and MRSA in clinical isolates were obtained from the SafetySurveillor®, a web-based data-mining tool used by the Infection Control and Prevention Department of our institution for managing infection control surveillance, prevention and reporting. Relative risk for MRSA infection was calculated for patients with positive versus negative MRSA screen results.

Results: A total of 14,456 MRSA screens were performed. Among 1,815 patients with positive screens, 132 subsequent cultures yielded MRSA. Among 12,641 patients with negative MRSA screens, 60 subsequent cultures yielded MRSA. Patients with positive MRSA cultures had a mean age of 58 years; the majority was females. Sites with MRSA isolates were abscesses/wounds, blood, sputum, urine, lines, and deep tissue or fluid. The relative risk for a positive MRSA culture after a positive screen was 15.3 (95% CI, 11.3-20.7; p<0.001). Excluding abscesses or wounds, the relative risk was 19.3 (95% CI, 12.8-29.0; p<0.001). Using only blood cultures to eliminate the possibility of MRSA colonization rather than infection, the relative risk was 13.9 (95% CI, 6.3-31.0; p<0.001).

Conclusion: MRSA nasal colonization substantially increases the likelihood that MRSA will be involved in infections which occur subsequently.

Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

Antonette Climaco, MD and Robert Fischer, M.D., Infectious Diseases, Albert Einstein Medical Center, Philadelphia, PA


A. Climaco, None

R. Fischer, None

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