Program Schedule

Vancomycin Minimum Inhibitory Concentration Does Not Predict Death, Recurrence or Readmission in Patients with Staphylococcus aureus Bacteremia in a Safety-Net Hospital

Session: Poster Abstract Session: Bacteremia: Staphylococcal Bacteremia
Friday, October 10, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
  • IDWeek 2014_Sanjiv Vanco Study_10.1.pdf (788.7 kB)
  • Background: Staphylococcus aureus (S. aureus) bacteremia (SAB) is a leading cause of bloodstream infections and results in tremendous health and financial burden. Prior studies examining the impact of the vancomycin minimum inhibitory concentration (MIC) on outcomes in patients with SAB have methodological and statistical limitations. The goal of this study was to determine whether increased vancomycin MIC is associated with higher risk for 90 day readmission, recurrence of disease or mortality in patients with SAB.

    Methods: This was a prospective cohort study of all adult patients with SAB  presenting to San Francisco General Hospital, the San Francisco County hospital, from 2008-2012. Subjects were identified by a hospital-wide infection surveillance system. The main predictor was vancomycin MIC, dichotomized as less than 2 mcg/mL or equal to 2 mcg/mL. The primary outcome was death within 90 days. Secondary outcomes were readmission or recurrence of disease within 90 days. Covariates included methicillin resistance, age, race, gender, severity of illness, co-morbidities, source of infection, injection drug use and all antibiotics administered over the study period with activity against Staphylococcus aureus. A survival analysis with a Cox proportional hazards model was used to estimate 90-day outcomes.

    Results: Of 437 unique first time cases of SAB, 23 patients were excluded for incomplete data, leaving 414 individuals with SAB for the final analysis. Eighty-two (19.8%) patients had a vancomycin MIC = 2 mcg/mL. 60 subjects (14.5%) died, 124 (30.0%) were re-admitted and 10 (2.4%) had recurrence of SAB within 90 days.  Multivariate regression showed equivalent risk of death (HR = 1.00, 95% CI (0.52, 1.91)), readmission (HR = 1.19, 95% CI (0.77, 1.85)) and recurrence (HR = 5.72 (95% CI (0.27, 123.56)) of SAB at 90 days for MIC < 2 versus MIC = 2.

    Conclusion: In this prospective cohort study, in which antibiotic treatment course and length of hospital stay were comprehensively measured and loss to follow-up was minimized, vancomycin MIC was not predictive of mortality, disease recurrence or readmission at 90 days in the treatment of SAB.

    Sanjiv Baxi, MS, MD, MPH, Medicine, The University of California San Francisco, San Francisco, CA, Angelo Clemenzi-Allen, MD, Medicine, University of California San Francisco, San Francisco, CA, Alice Gahbauer, PharmD, Pharmacy, University of Pittsburgh, Pittsburgh, PA, Daniel Deck, PharmD, Department of Pharmaceutical Services, San Francisco General Hospital, San Francisco, CA, Brandon Imp, Medicine, Robert Wood Johnson Medical School, New Brunswick, NJ, Sarah Doernberg, MD, University of California, San Francisco, San Francisco, CA and Henry Chambers, MD, FIDSA, University of California, San Francisco General Hospital, San Francisco, CA


    S. Baxi, None

    A. Clemenzi-Allen, None

    A. Gahbauer, None

    D. Deck, Forest Pharmaceuticals: speaker, Speaker honorarium
    Merck: speaker, Speaker honorarium

    B. Imp, None

    S. Doernberg, None

    H. Chambers, None

    Findings in the abstracts are embargoed until 12:01 a.m. EDT, Oct. 8th with the exception of research findings presented at the IDWeek press conferences.

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