830. Risk Factors for viridans group streptococcal bacteremia in neutropenic and non-neutropenic patients at the NIH Clinical Center, 2009-2014: A case-case-control study
Session: Poster Abstract Session: Bacteremia and Endocarditis
Friday, October 9, 2015
Room: Poster Hall
Posters
  • S. viridans Poster IDWeek2015 151005.pdf (455.0 kB)
  • Background: Viridans group streptococci (VGS) cause bacteremia and sepsis among neutropenic patients (NP); known risk factors include mucositis and fluoroquinolone prophylaxis, and gram-positive antimicrobial coverage can prevent or preempt VGS sepsis. Although VGS bacteremia occurs in non-NP, risk factors for such patients are not well established. Given a limited pool of potential controls, we conducted a case-case-control study to identify risk factors for VGS among NP and non-NP in our 240-bed clinical research hospital.

    Methods: Patients with VGS bacteremia between 1/2009 and 12/2014 were identified using microbiology records. Twelve whose culture results had been deemed to be contaminants were excluded. NP and non-NP patients at the time of positive culture were matched 1:1 to controls on the basis of ANC ≤ or >1000/mm3, respectively, hospital ward, and length of stay. We extracted demographic data, ANC, medications, chemotherapy, radiation therapy, mucositis and other oral inflammatory conditions, and GI conditions (e.g., C. difficile infection, graft-versus-host disease, typhlitis). Data were analyzed using McNemar’s test, Wilcoxon signed-rank test, and conditional logistic regression modeling.

    Results: Among 101 patients, 63 were NP and 38 non-NP at the time of VGS bacteremia. No clinical factors were associated with VGS in non-NP. Among NP, however, VGS bacteremia was associated with lower ANC (p<0.0001), radiation therapy (p=0.0164), cyclophosphamide (p=0.0067) fludarabine (p=0.0143), mucositis (p=-0.039) and other oral inflammatory conditions (p=0.0105). In multivariable analysis of NP, only lower ANC predicted status as a case (OR=0.006, 95% CI: 0.001-0.134; p=0.0012). 

    Conclusion: The well-described risk factors for VGS bacteremia in NP did not predict infection in non-NP, possibly due to sample size or to the heterogeneity of the latter group. NP who had lower nadirs were more vulnerable to VGS bacteremia. Other associations in NP (chemotherapy, radiation, oral conditions) are all related to neutropenia. Further analyses will explore antibiotic exposure. Identification of modifiable risk factors may enable prevention among patients with adequate granulocytes.

    Augusto Dulanto Chiang, M.D.1, Ninet Sinaii, Ph.D., M.P.H.2, Christine D. Spalding, M.S.3, David K. Henderson, M.D.4 and Tara N. Palmore, M.D.3, (1)Department of Internal Medicine, Medstar Washington Hospital Center, Washington, DC, (2)Biostatistics and Clinical Epidemiology Service, National Institutes of Health Clinical Center, Bethesda, MD, (3)Hospital Epidemiology Service, National Institutes of Health Clinical Center, Bethesda, MD, (4)National Institutes of Health Clinical Center, Bethesda, MD

    Disclosures:

    A. Dulanto Chiang, None

    N. Sinaii, None

    C. D. Spalding, None

    D. K. Henderson, None

    T. N. Palmore, None

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