380. Risk Factors for Isolation of Daptomycin Non-Susceptible Enterococci: A Case-Case Control Study
Session: Poster Abstract Session: MRSA, MSSA, Enterococci
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Posters
  • DNSE RF Poster IDWEEK 2013.pdf (403.3 kB)
  • Background: An increase in daptomycin non-susceptible enterococci (DNSE) at our institution was determined to be non-clonal in nature.  We sought to define risk factors for DNSE.    

    Methods: : We performed a retrospective case-case control study with case group 1 patients having daptomycin non-susceptible (by broth microdilution) vancomycin-resistant Enterococcus faecium(DNS-VRE) from a clinical culture (N=17) matched to case group 2 (daptomycin susceptible VRE, DS-VRE) and non-infected controls in a 1:1:3 ratio by ward location, culture site, and time period (+/- 4 months).  Conditional logistic regression models identified individual risk factors for DNS-VRE and DS-VRE respectively compared to controls.  For each outcome, a multiple conditional logistic regression model was developed based on risk factors identified on univariate analysis.  Models were qualitatively compared to identify DNS-VRE risk factors.

    Results: Demographic characteristics and prior antibiotic exposure was not significantly different between case groups.  Table displays univariate analysis of DNS-VRE and DS-VRE risk factors.  Daptomycin use was rare (2 DNS-VRE, 1 DS-VRE, 0 controls) and not able to be included in the model.  

    DNS-VRE

    DS-VRE

    Odds Ratio

    p

    Odds Ratio

    p

    Duration Index Hospitalization

    1.06

    .0498

    1.07

    .009

    Duration Hospitalization Prior to Culture

    1.35

    .0052

    1.12

    .0408

    DOT Antibiotics in 90 days Prior to Culture

    1.03

    .0179

    1.02

    .0237

    Receipt of Vancomycin

    8.92

    .0055

    3.98

    .0499

    Receipt of Linezolid

    15

    .0134

    6.00

    .1435

    Receipt of Fluoroquinolone

    3.12

    .0655

    4.48

    .0276

    Receipt of Cephalosporin

    2.33

    .141

    4.52

    .0278

    Receipt of Charlson Score

    1.16

    .1778

    1.33

    .0261

    Risk factors for DNS-VRE by multivariate analysis: duration of index hospitalization (OR 1.32, p=.0327) and DOT in 90 days PTC (OR 1.03, p=.0462).  Risk factors for DS-VRE: DOT in 90 days PTC (OR 1.03, p=.0417), Charlson score (OR 2.41, p=.0286) and fluoroquinolone PTC (OR 8.07, p=.0306).

    Conclusion: Daptomycin exposure was uncommon and not a risk factor for DNS-VRE, but recent exposure to antimicrobials was a risk factor for isolation of both DS- and DNS-VRE.  Duration of hospitalization was the only risk factor unique to isolation of DNS-VRE.  Additional studies with a greater number of patients with DNSE are needed to further define risk factors for daptomycin non-susceptibility.

    Neha Balmoori, MD1, Alan Gross, PharmD2, Andre C. Kalil, MD, MPH3, Elizabeth Lyden, MS4, Mark E. Rupp, MD, FIDSA, FSHEA3 and Trevor C. Van Schooneveld, MD1, (1)Internal Medicine, University of Nebraska Medical Center, Omaha, NE, (2)Nebraska Medical Center, Omaha, NE, (3)Internal Med., Univ. of Nebraska Med. Ctr., Omaha, NE, (4)University of Nebraska Medical Center, Omaha, NE

    Disclosures:

    N. Balmoori, None

    A. Gross, None

    A. C. Kalil, None

    E. Lyden, None

    M. E. Rupp, None

    T. C. Van Schooneveld, Cubist: Research Contractor and Scientific Advisor, Consulting fee and Research support

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