1065. Characterization of Recurrent Methicillin-resistant Staphylococcus aureus Bloodstream Infections
Session: Poster Abstract Session: Clinical Infectious Diseases: Bacteremia and Endocarditis
Friday, October 28, 2016
Room: Poster Hall
Posters
  • FINAL idsa POSTER 10.19.2016.pdf (308.8 kB)
  • Background:

    Little is known about the clinical characteristics of patients (pts) with methicillin-resistant Staphylococcus aureus(MRSA) bloodstream infection (BSI) that are associated with recurrent BSI (RBSI).

    Methods:

    A retrospective chart review study was done in an integrated 4 hospital health system in Michigan. 1173 consecutive pts with MRSA BSI were evaluated from 2005 to 2014. RBSI was defined as a positive blood culture ≥30 days after completing treatment (tx) for the initial BSI (IBSI). Characteristics of pts with RBSI were compared to ones without. Vancomycin (VAN) and daptomycin (DAP) susceptibility was determined using Etest. Isolates were typed using pulsed field gel electrophoresis (PFGE). Comparisons were done using chi-square and t-test in SAS 9.4.

    Results:

    Of 1173 pts with MRSA BSI, 896 met criteria. 71 (7.9%) experienced RBSI in a median of 258.5 days (range 31-2288). The average age in RBSI was 52.2 vs 59.1 years in the control group (p <0.001). Table 1 shows characteristics of the pts. The average duration of IBSI in pts with RBSI was 4.3 (± 3.8) days; 15.5% cases had a duration ≥ 7 days. The source of RBSI was the same as in IBSI in 43 cases (61%): line in 39.5% and endocarditis in 32.6% of cases. Among MRSA isolates, the mean VAN MIC in IBSI was 1.6 (± 0.2) µg/ml vs 1.56 (± 0.39) µg/ml for RBSI. 84.5% had same or decreased VAN MIC in RBSI. For DAP, mean MIC was 0.52 (±0.17) µg/ml in IBSI and 0.66 µg/ml (± 0.44) for RBSI, with increase in DAP MIC in 45.7%. In IBSI, USA 300 (46.5%) and USA 100 (40.8%) were the most common strains. Of the RBSI, 76% had the same CDC group as IBSI.

    Table 1. Characteristics of pts with RBSI and without

    Pts with RBSI

    N = 71

    %

    Pts without RBSI

    N=825

    %

    p value

    Source

    Line

    Unknown

    Skin/wound

    Endocarditis

    41

    11

    17

    21

    20

    19

    36

    9

    <0.001

    Comorbidities

    Acute renal failure (RF)

    Chronic RF

    Dialysis

    Hepatitis

    3

    44

    41

    28

    16

    32

    20

    15

    0.003

    0.042

    <0.001

    0.041

    Epidemiological acquisition

    Community-acquired

    Healthcare-associated

    Hospital-acquired

    17

    65

    18

    33

    52

    15

     0.016

    VAN MIC

    (mean)

     1.6 ± 0.2

    1.6 ± 0.3

     0.580

     

    Conclusion:

    MRSA RBSI, though uncommon, is generally of the same source and with isolates of the same CDC group. VAN is the most commonly used tx, with 84.5% of isolates showing no increase in VAN MIC of RBSI. Source, epidemiological acquisition and comorbidities are risk factors associated with RBSI.

    Ayesha Niazy, MD1, Ana C. Bardossy, MD1, Khulood Rizvi, MD2, Tooba Rehman, MD1, Pamela Hartman, B.S.3, Daniela Moreno, MPH4, Mary Beth Perri, MT4 and Marcus Zervos, MD5, (1)Division of Infectious Diseases, Henry Ford Health System, Detroit, MI, (2)Division of Infectious Diseases, Henry Ford Health System, Detriot, MI, (3)Infectious Diseases, Henry Ford Health System, Detroit, MI, (4)Henry Ford Health System, Detroit, MI, (5)Division of Infectious Diseases, Henry Ford Hospital, Detroit, MI

    Disclosures:

    A. Niazy, None

    A. C. Bardossy, None

    K. Rizvi, None

    T. Rehman, None

    P. Hartman, None

    D. Moreno, None

    M. B. Perri, None

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

    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.