1225. High rate of linezolid (LZD) non-susceptibility (LNS) among enteric vancomycin-resistant enterococci (VRE) recovered from hospitalized patients actively screened for VRE rectal colonization (VREC)
Session: Poster Abstract Session: Healthcare Epidemiology: MSSA, MRSA and Other Gram Positive Infections
Friday, October 5, 2018
Room: S Poster Hall
Posters
  • VRE Rectal Swab Poster IDWeek 2018_FINAL.pdf (255.4 kB)
  • Background: Select hospitalized patients are actively screened for VREC but VRE isolates may not undergo antibiotic susceptibility testing. We sought to identify predictors of daptomycin (DAP) non-susceptibility (DNS, MIC > 4) and LNS (MIC > 2) among enteric VRE isolates recovered from patients actively screened for VREC for which antibiotic susceptibility testing was not preformed.

    Methods: This was a retrospective study of consecutive adults admitted to a surgical intensive care unit (ICU) or associated medical unit between 6/1/17 and 3/1/18 who had a VRE isolate from active screening. Only index isolates were included. DAP and LZD MICs were determined by Etest. Patient- and antimicrobial-level data, including ambulatory prescriptions, dating back to 1/1/16 were collected. Multivariable logistic regression models were used to determine predictors of DNS and LNS VRE.

    Results: In total, 64 patients’ VRE rectal isolates were included. Fifty-nine (92.2%) were E. faecium and 50 (78.1%) were from ICU patients. Thirty-seven patients (57.8%) were female and the mean age ± SD was 60 ± 13 years. Five (7.8%) and 20 (31.3%) patients had previous abdominal transplant and VRE infection, respectively. DAP and LZD MIC distributions are shown in the table below. Forty-one (64.1%) VRE isolates were LNS, including 5 LZD-resistant isolates. Only one (1.6%) isolate was DNS precluding an analysis of DNS predictors; 12 (18.8%) isolates had a DAP MIC > 2mg/L. Common antimicrobial exposures prior to index VRE isolate included: vancomycin (62.5%), ceftriaxone (64.1%), cefepime (53.1%), metronidazole (50%), and ciprofloxacin (50%). Previous LZD (17.2%) and DAP (15.6%) exposure were less common. In a multivariable model, number of previous cefazolin doses (adjusted odds ratio (aOR) 0.74 95% confidence interval (CI) 0.55 – 0.95) and previous tobramycin exposure (aOR 0.15, 95% CI 0.02 – 0.81) were inversely associated with LNS. Previous LZD exposure was not associated with LNS.

    MIC50

    MIC90

    DAP

    1.5mg/L

    3mg/L

    LZD

    4mg/L

    4mg/L

    Conclusion: LNS was common amongst VRE isolates in this cohort. Previous LZD exposure was infrequent and not associated with LNS. LZD susceptibility testing among VRE isolates recovered from patients actively screened for VREC warrants clinical consideration.

    Thomas J. Dilworth, PharmD1, Eric Beck, PhD2, Rachel Pedersen, BA3, Waseem Al-Karkokly, BS2, Margaret Cook, PharmD1, Erika Aldag, PharmD1, David J. Kramer, MD4, Ajay Sahajpal, MD3, Iram Nadeem, MD5, Brian Buggy, MD5 and Charles F. Brummitt, MD5, (1)Department of Pharmacy Services, Aurora Health Care, Milwaukee, WI, (2)ACL Microbiology Laboratory, West Allis, WI, (3)Department of Abdominal Transplant, Aurora Health Care, Milwaukee, WI, (4)Department of Critical Care Medicine, Aurora Health Care, Milwaukee, WI, (5)Infectious Diseases Section, Aurora Health Care, Milwaukee, WI

    Disclosures:

    T. J. Dilworth, None

    E. Beck, None

    R. Pedersen, None

    W. Al-Karkokly, None

    M. Cook, None

    E. Aldag, None

    D. J. Kramer, None

    A. Sahajpal, None

    I. Nadeem, None

    B. Buggy, None

    C. F. Brummitt, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.