483. Results of an Outbreak Investigation of MRSA Colonization in MICU Patients
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Background: Patients newly colonized with MRSA are at higher risk of MRSA infections. In our program for active surveillance for MRSA colonization by PCR, we recently demonstrated a significant increase in the rate of MRSA colonization in patients in the MICU. The objective of this study was to describe the findings of our MRSA colonization outbreak investigation.
Methods: The CDC 10 steps methodology for outbreak investigation was followed.
Results: Before June 2007 the expected rate of MRSA colonization was stable at 1% per month. On July 2007 the observed rate was 6% (p=0.0024). After analysis of the line listing, a common room was identified in the MICU which hosted 4 of the 7 patients colonized. Follow-up of all newly colonized patients indicated development of MRSA VAP in one of the patients. DNA fingerprinting using a repetitive sequence-based PCR (rep-PCR) for the microbial DNA typing was available from 6 of the 7 isolates. Fingerprinting results showed a percentage similarity > 80% in 4 isolates, with 2 isolates being 99% similar. It was concluded that environmental transmission of MRSA from a single room was the cause of the outbreak. Terminal cleaning was performed. Follow-up surveillance indicated a rate of colonization that return to baseline.
Conclusion: This study demonstrates that active surveillance of MRSA in hospitalized patients is beneficial to detect increased rates of colonization. By controlling an outbreak of MRSA colonization, we may have prevented MRSA infections in our MICU patients.
Susan Blake, RN, MBA, OCN1, Lorre Coates, RN, BSN1, Janice Lattus, RN, MPH, CIC2, Raul Nakamatsu, MD3, Paula Peyrani, MD, Julio Ramirez, MD3, Joanna Sarver, RN, BSN1, Carmen Sciortino, PhD3 and  P. Peyrani, None..
J. Sarver, None..
J. Lattus, None..
L. Coates, None..
S. Blake, None..
R. Nakamatsu, None..
C. Sciortino, None..
J. Ramirez, None., (1)Veterans Affairs Medical Center, Louisville, KY, (2)Veterans Affair Medical Center, Louisville, KY, (3)University of Louisville, Louisville, KY