428. Point Prevalence by PCR of Clostridium difficile Colonization in Hospitalized Infants is Lower Than Previously Reported
Session: Poster Abstract Session: Pediatric Infections
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
  • NICU C diff poster 2013.pdf (3.5 MB)
  • Background:

    We examined the point prevalence of asymptomatic C. difficile colonization in hospitalized infants from two affiliated NICUs utilizing standard clinical testing and developed a novel duplex PCR to identify toxigenic and non-toxigenic C. difficile strains.


    All infants in NICUs at two separate, affiliated centers were eligible for inclusion.  Stool collection (in diapers), without any patient identifiers or characteristics, occurred during a one week time period for each NICU and was repeated 6 months later to increase sample size.  Stool samples were tested for C. difficile by EIA (GDH/toxin A/B); samples testing +/+ or +/- were evaluated reflexively via LAMP PCR as well as by our novel PCR amplification of Toxin B and tpi (housekeeping) genes, to distinguish toxigenic and non-toxigenic C.difficile types.  Cytotoxicity assays were performed on all samples positive by any modality. 


    84 samples were collected from unique infants and EIA showed: 71 -/-, 7 +/- and 6 +/+. All 6 EIA +/+ samples (6/84 [7.1%]) were confirmed as toxigenic C. difficile by LAMP; 6/7 EIA +/- were negative by LAMP, one invalid.  Duplex PCR concurred with LAMP in the 6/84 positive for toxigenic C. difficile.  It revealed 2 additional EIA -/- to be positive for tpi gene, indicating non-toxigenic C. difficile. Cytotoxicity assay was performed for additional confirmation, and was positive for 4/6 duplex PCR positive samples, 2 could not be confirmed.  All samples EIA +/- but PCR negative were also cytotoxicity negative.


    Point prevalence by PCR of C. difficile asymptomatic colonization in hospitalized infants in NICUs is much lower than previous estimates.  PCR may allow for more accurate estimates than traditional cytotoxicity assays; our new duplex PCR had excellent concordance with LAMP and EIA tests.  Evolving NICU care and nutritional practices may be altering the composition of gut microbiota and reducing the prevalence of C. difficile colonization.

    Kari Simonsen, MD1, Xing Zhao, MD2, Andrea Green Hines, M.D.3, Ann Anderson-Berry, MD4, Lynne Willett, MD4, Peter C. Iwen, PhD.5, Alyssa Hornay6, Hendrik Viljoen, PhD7 and Alison Freifeld, MD8, (1)Pediatrics, Infectious Diseases, University of Nebraska Medical Center, Omaha, NE, (2)Medicine, University of Nebraska Medical Center, Omaha, NE, (3)Infectious Diseases, University of Nebraska Medical Center, Omaha, NE, (4)Pediatrics, Neonatology, University of Nebraska Medical Center, Omaha, NE, (5)University of Nebraska Medical Center, Omaha, NE, (6)Pathology, Microbiology, University of Nebraska Medical Center, Omaha, NE, (7)Division of Infectious Diseases, University of Nebraska Medical Center, Omaha, NE, (8)Univ of Nebraska, Omaha, NE


    K. Simonsen, None

    X. Zhao, None

    A. Green Hines, None

    A. Anderson-Berry, None

    L. Willett, None

    P. C. Iwen, None

    A. Hornay, None

    H. Viljoen, Streck, Inc: Consultant, Research support

    A. Freifeld, Streck, Inc: Consultant, Research support

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