226. Effect of Rapid PCR MRSA Testing on Empiric Antibiotic Prescribing for Patients Hospitalized with Skin and Soft Tissue Infections
Session: Poster Abstract Session: Antimicrobial Stewardship in Clinical Practice
Friday, October 21, 2011
Room: Poster Hall B1
  • 226_AnushaKrishnadasan.pdf (226.4 kB)
  • Background: 

    Since MRSA emerged, empiric vancomycin for skin and soft tissue infections (SSTI) has increased dramatically. While common, MRSA is inconsistently cultured from complicated SSTI. Inappropriate antibiotic use until culture and susceptibility results are available can lead to treatment failure, promotion of resistance, and increased costs. Therefore, we hypothesized that rapid wound PCR testing for MRSA/S. aureus (GeneXpert, Cepheid, Inc.) in the emergency department (ED) would reduce inappropriate antibiotic use for patients hospitalized with SSTI.


    Medical records were retrospectively reviewed for adults hospitalized for SSTI with drainage from the ED at a Los Angeles county hospital between March 2009 and November 2010 over three consecutive periods: Phase I, before GeneXpert; Phase II, after GeneXpert introduction with physician education; Phase III, with active PharmD direction of physicians based on GeneXpert results. Medical students blinded to the study hypothesis reviewed records. Data collected included demographic, clinical, hospital duration, wound culture and GeneXpert results, and antibiotic use. Antibiotics were considered inappropriate if MRSA-active antibiotics were given and MRSA was not grown in cultures, or if MRSA-active antibiotics were not given and MRSA was grown. Median days of inappropriate antibiotics and vancomycin were compared between Phase I and later periods.


    MRSA was cultured from 15/53 (28%), 13/47 (28%), and 18/61 (30%) of Phase I, II, and III patients, respectively. Median days inappropriate antibiotic use were 0.6 in Phase I, 0.7 in Phase II (p=0.33) and 0.2 in Phase III (p=0.07). Among patients whose cultures did not grow MRSA, median days inappropriate antibiotics were 1.5 in Phase I, 1.5 in Phase II (p=0.19), and 0.7 in Phase III (p=0.04), and median days vancomycin were 1.2 in Phase I, 1.5 in Phase II (p=0.15), and 0.5 in Phase III (p=0.04).  On hospital discharge, 33% of Phase I patients, 32% in Phase II (p=0.93) and 22% in Phase III (p=0.21) received inappropriate antibiotics.


    Rapid PCR MRSA/S. aureus testing can decrease inappropriate antibiotic use, particularly vancomycin use among patients with non-MRSA SSTI, especially when physicians are advised by a PharmD.

    Subject Category: J. Clinical practice issues

    David Talan, MD1,2, Anusha Krishnadasan, PhD1, Sophie Terp, MD1,2, William Bowen, MD1, Simon Alarcon, BS1, Daniel Furoy, MD1,2 and Gregory Moran, MD1,2, (1)Emergency Medicine, Olive View-UCLA Medical Center, Sylmar, CA, (2)David Geffen School of Medicine at UCLA, Los Angeles, CA


    D. Talan, Cepheid: Investigator, Research support

    A. Krishnadasan, None

    S. Terp, None

    W. Bowen, None

    S. Alarcon, None

    D. Furoy, None

    G. Moran, None

    Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.