238. Broad-range PCR application in a large academic pediatric center: Clinical value and challenges
Session: Poster Abstract Session: Diagnostics: Miscellaneous
Thursday, October 8, 2015
Room: Poster Hall
Posters
  • IDSA BRPCR poster.pdf (768.0 kB)
  • Background: Broad-range polymerase chain reaction (BR-PCR) has been used to detect infectious pathogens from patient specimens using targets for bacterial (16S rRNA), fungal (28S rDNA) and mycobacterial (FRET and heat shock protein 65 gene); diagnostic sensitivity and specificity range from 43-100% and 100% respectively. At Nationwide Children’s Hospital (NCH), BR-PCR is often requested on clinical specimens from immunocompromised patients (ICP) and those treated with antibiotics before obtaining clinical samples for culture, so we sought to describe the utility of BR-PCR in improving diagnostic yield. 

    Methods: Retrospective analysis of clinical samples obtained from the NCH microbiology laboratory from January 2011 - December 2014 and sent for BR-PCR to the University of Washington Molecular Diagnostics Lab. Medical record review collected data on patient characteristics, clinical scenario and laboratory results, and a determination of clinical value was assigned.

    Results: 256 samples from 157 patients were identified of which 45% (N=71) were ICP and 77% (N=196) of samples were from patients who had received antibiotics prior to sample acquisition.  BR-PCR detected a causative organism in 39 samples and was the sole positive diagnostic result for 20 samples (8%).  BR-PCR failed to detect the causative agent in 27 (10%) of samples that were confirmed by other diagnostic methods (N = 24 by culture, N= 5 by serology, N=1 by pathology, N=2 by culture/pathology).  Yield was lowest among acid-fast (AFB) organism infections diagnosed in our cohort; BR-PCR did not detect AFB DNA in all 5 cases of microbiologically proven infection.  Among samples, bronchoalveolar lavage (BAL) was the type most commonly sent (N=77); however, no organisms were detected by BR-PCR that were not already confirmed via a conventional method.  BR-PCR detected an organism from tissue samples more than from  BAL or other fluids (p= 0.05, Chi square).

    Conclusion: In our cohort, BR-PCR was helpful as an adjunctive diagnostic in identifying infectious organisms in patients previously exposed to antibiotics, but lacked sensitivity for detection in BAL samples and AFB infections.  Additional data is needed to better define the optimal clinical scenarios and specimen type in which it can provide the highest diagnostic yield.

    Elizabeth Lucas, MD, Complex Healthcare, Nationwide Children's Hospital, Columbus, OH, Amy Leber, PhD, Department of Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH and Monica I. Ardura, DO, MSCS, Pediatrics, Infectious Diseases and Immunology, The Ohio State University and Nationwide Children’s Hospital, Columbus, OH

    Disclosures:

    E. Lucas, None

    A. Leber, Biofire: Scientific Advisor , Research support

    M. I. Ardura, None

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