1612. Outcomes of an Enhanced Surveillance Program for Carbapenem-resistant Enterobacteriaceae (CRE)
Session: Poster Abstract Session: Multidrug-Resistant Gram Negative Rods
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
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  • Background:

    Both acute and long-term acute care hospitals (LTACH) have seen an alarming increase in the prevalence of CRE. We studied two strategies to control the spread of CRE: 1.) screening patients with epidemiologic links to unrecognized CRE colonized or infected patients (ring surveillance, RS), and 2.) improving CRE culture detection (culture validation, CV).


    Hospitalized patients with CRE cultures between Sep 2011 and Jan 2013 were included. In the RS study, new CRE patients not on contact precautions triggered rectal surveillance of all patients on the same ward.  In the CV study, two rectal swabs were obtained from patients already on contact precautions with CRE cultures. Swab #1 was plated directly on vancomycin, amphotericin B, ceftazidime, and clindamycin (VACC) plates with ertapenem resistance confirmed by Kirby-Bauer. Swab #2 was inoculated in ertapenem-enriched media (EEM) prior to plating. Polymerase chain reaction for the Klebsiella pneumoniae carbapenemase gene and pulsed-field gel electrophoresis (PFGE) were performed as indicated. Patient charts were reviewed and clinical characteristics and outcomes recorded.


    RS occurred 14 times, included 173 patients and identified two patients with CRE colonization. These patient's strains were unrelated to the index patient by PFGE. See Table for clinical details. One patient who was negative during RS subsequently had a positive culture for CRE that was closely related by PFGE to the index strain. In addition, seven other new CRE positive patients shared time on wards with CRE positive patients outside of the timeframe of RS. PFGE typing confirmed two possible transmissions in this group. In the CV study, the sensitivity of direct plating on VACC plates compared with inoculation in EEM was 91% vs. 100%. Both methods had 100% specificity.


    RS study  (n=14)

    CV study (n=25)

    Mean age, yr



    Female (%)



    Recent hospital, LTACH, or nursing facility exposure (%)



    Prior antibiotic use during hospital stay(%)



    Mean Charlson score



    Hosp mortality (%)




    RS identified patients with unrecognized CRE colonization, but failed to comprehensively capture CRE transmissions.  Further refinement of RS strategy is recommended.  Inoculation of rectal swabs in EEM prior to plating increases the sensitivity of detecting CRE.

    Margaret Fitzpatrick, MD1, Teresa Zembower, MD, MPH1, Chao Qi, PhD2, Michael Malczynski, BS3 and Maureen K. Bolon, MD, MS1, (1)Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL, (2)Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, (3)Microbiology, Northwestern Memorial Hospital, Chicago, IL


    M. Fitzpatrick, None

    T. Zembower, None

    C. Qi, None

    M. Malczynski, None

    M. K. Bolon, None

    Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.