1005. Real-time PCR Assays on Dried Blood Spots for Detection of Streptococcus pneumoniae in Febrile Children: A Surveillance Diagnostic Method for Resource-limited Settings
Session: Poster Abstract Session: Diagnostic Microbiology: Streptococci
Friday, October 9, 2015
Room: Poster Hall
  • Iroh Tam DBS poster .pdf (765.5 kB)
  • Background: Streptococcus pneumoniae is the leading infectious cause of mortality in Nigeria. A major challenge in accurately determining the prevalence of pneumococcal disease is the lack of resources that make it possible to process diagnostic specimens. Dried blood spot (DBS) testing is an ideal method for diagnosis of infections in the developing world because of its low cost, minimal blood volumes involved, and ability for storage at ambient temperature. Using DBS collected from a prospective cohort of febrile children in Nigeria, we hypothesized that molecular methods would be more sensitive than culture in the detection of S. pneumoniae bacteremia.

    Methods: Children 5 years of age or under who presented to six hospital study sites throughout northern and central Nigeria with an acute febrile illness (Temp >38.5 oC) associated with difficulty breathing or altered consciousness, were prospectively enrolled from September 2011 through June 2015. Blood was obtained for culture using the automated Bactec incubator system and also spotted onto filter paper. DBS DNA extractions were used as a template in rt-PCR assays with the lytA gene, and RNase P was used as a control to assess the extraction of human cellular DNA.

    Results: A total of 270 DBS were evaluated, of which 8 were culture-positive for S. pneumoniae, and 8 were positive by PCR (3.0% each). One culture-confirmed case was missed, and PCR identified one culture-negative specimen from a high-risk group. 

    Conclusion:   Rt-PCR detection of S. pneumoniae in DBS led to an equivalent detection of the pathogen compared to conventional blood culture, and was able to detect S. pneumoniae in culture-negative specimens. PCR assays from DBS are a valuable diagnostic method suitable for conducting surveillance and can provide precise assessments of the effect of conjugate vaccines in resource-limited settings.

    Pui-Ying Iroh Tam, MD, Pediatrics, University of Minnesota Medical School, Minneapolis, MN, Nelmary Hernandez-Alvarado, MS, Center for Infectious Diseases, Microbiology and Translational Research, Minneapolis, MN, Mark R. Schleiss, MD, Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN and Stephen K. Obaro, MD, PhD, FIDSA, FPIDS, University of Nebraska Medical Center, Omaha, NE


    P. Y. Iroh Tam, None

    N. Hernandez-Alvarado, None

    M. R. Schleiss, None

    S. K. Obaro, GENDRIVAX: Scientific Advisor , Travel support
    GSK: Investigator , Grant recipient
    PFIZER: Investigator , Grant recipient

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