1063. Vancomycin Serum Trough Levels and Outcomes in Patients with Methicillin-Resistant Staphylococcus aureus Bacteremia
Session: Poster Abstract Session: Clinical Infectious Diseases: Bacteremia and Endocarditis
Friday, October 28, 2016
Room: Poster Hall
Posters
  • Poster PDF.pdf (517.1 kB)
  • Background: 

    Methicillin-resistant Staphylococcus aureus(MRSA) bacteremia is a major cause of morbidity and mortality. Vancomycin (VAN) is considered the first line antimicrobial agent for its treatment. Current IDSA guidelines recommend VAN trough levels between 15 and 20 μg/ml for MRSA bacteremia. We sought to compare MRSA bacteremia outcomes in relation to VAN serum trough levels.

    Methods: 

    This is a retrospective study performed in an integrated 4 hospital health system in southeast Michigan. We evaluated consecutive patients with MRSA bacteremia who were only treated with VAN from 2011 to 2015. Data was obtained via review of electronic medical records. Patients were included if they were > 18 years of age and had evidence of positive blood culture for MRSA. Patients who received daptomycin, ceftaroline or linezolid were excluded. We evaluated initial VAN serum trough level (collection within 30-72 hours from the first dose) and mean VAN level (mean of serial VAN serum trough levels). Patients were subdivided in two groups of low (<15 μg/ml) and high (>15 μg/ml) VAN serum trough levels. VAN MICs were determined by E-test for all isolates. Univariate two-group comparisons were performed using t-tests, Chi-squared test and Fisher’s exact test (SAS 9.4; Cary, NC).

    Results: 

    Out of 587 patients, 187 met the inclusion criteria. The two groups had similar characteristics. There was significantly higher mortality within 60 days of index blood culture in the group with high initial VAN serum trough levels (see Table 1). Furthermore, mortality within 30 days of index blood culture was even more significantly higher in group with the high mean VAN serum trough level. Duration of bacteremia was also longer in the high mean VAN serum trough level group (see Table 2).

    Table 1. Outcome comparisons in initial group

     

    Initial High Group

    (>15 μg/ml)

     

    Initial Low Group

    (<15 μg/ml)

    p value

     

    Mortality within 60 days

     

     

    26%

     

    11%

     

    0.04

     

    Table 2. Outcome comparisons in mean group

     

    Mean High Group

    (>15 μg/ml)

    Mean Low Group

    (<15 μg/ml)

    p value

     

    Mortality within 30 days

     

     

    14%

     

    0%

     

    0.022

    Duration of bacteremia mean no. of days (SD)

     

    2.9 (2.5)

     

    2.1 (1.4)

     

    0.025

     

    Conclusion: 

    We demonstrated that high VAN serum trough concentrations >15 μg/ml were associated with worst outcomes. However, future prospective randomized trials are warranted.

    Tooba Rehman, MD1, Vanthida Huang, PharmD2, Yuan Xin, MPH3, Khulood Rizvi, MD4, Ayesha Niazy, MD1, Ana C. Bardossy, MD1 and Marcus Zervos, MD5, (1)Division of Infectious Diseases, Henry Ford Health System, Detroit, MI, (2)College of Pharmacy, Midwestern University, Glendale, AZ, (3)Public Health Sciences/Henry Ford Health System, Detroit, MI, (4)Division of Infectious Diseases, Henry Ford Health System, Detriot, MI, (5)Division of Infectious Diseases, Henry Ford Hospital, Detroit, MI

    Disclosures:

    T. Rehman, None

    V. Huang, None

    Y. Xin, None

    K. Rizvi, None

    A. Niazy, None

    A. C. Bardossy, None

    M. Zervos, Pfizer: Research Contractor , Research support
    Cerexa: Research Contractor , Research support
    Cubist: Research Contractor , Research support
    Merck: Research Contractor , Research support
    Tetraphase: Research Contractor , Research support
    Melinta: Research Contractor , Research support
    Paratek: Research Contractor , Research support
    Rempex: Research Contractor , Research support
    Cempra: Grant Investigator , Research support

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.