Research

Molecular Biotechnology

, Volume 42, Issue 1, pp 117-127

First online:

Molecular Detection of Streptococcus pyogenes and Streptococcus dysgalactiae subsp. equisimilis

  • Erica D. DawsonAffiliated withInDevR Inc. Email author 
  • , Amber W. TaylorAffiliated withInDevR Inc.
  • , James A. SmagalaAffiliated withInDevR Inc.Influenza Division, The Centers for Disease Control and Prevention
  • , Kathy L. RowlenAffiliated withInDevR Inc.

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Abstract

We developed molecular diagnostic assays for the detection of Streptococcus pyogenes (GAS) and Streptococcus dysgalactiae subsp. equisimilis (SDSE), two streptococcal pathogens known to cause both pharyngitis and more invasive forms of disease in humans. Two real-time PCR assays coupled with an internal control were designed to be performed in parallel. One assay utilizes a gene target specific to GAS, and the other utilizes a gene target common to the two species. Both assays showed 2–3 orders of magnitude improved analytical sensitivity when compared to a commercially available rapid antigen test. In addition, when compared to standard culture in an analysis of 96 throat swabs, the real-time PCR assays resulted in clinical sensitivity and specificity of 91.7 and 100%, respectively. As capital equipment costs for real-time PCR can be prohibitive in smaller laboratories, the real-time PCR assays were converted to a low-density microarray format designed to function with an inexpensive photopolymerization-based non-enzymatic signal amplification (NESA™) method. S. pyogenes was successfully detected on the low-density microarray in less than 4 h from sample extraction through detection.

Keywords

Streptococcus pyogenes Streptococcus dysgalactiae subspecies equisimilis Real-time PCR Low-density microarray Molecular diagnostics Pathogen detection