Molecular Detection of Streptococcus pyogenes by Strand Invasion Based Amplification Assay.

Introduction: Streptococcus pyogenes (group A Streptococcus, GAS) is responsible for a variety of highly communicable infections, accounting for 5-15 and 20-30% of sore throat hospital visits in adults and children, respectively. Prompt diagnosis of GAS can improve the quality of patient care and minimize the unnecessary use of antibiotics.

Objective: Our objective was to develop an alternative nucleic acid amplification method for the diagnosis of GAS.

Method: We developed and evaluated a strand invasion based amplification (SIBA) assay to rapidly and specifically detect GAS. The performance of the developed GAS SIBA assay was compared with an established GAS polymerase chain reaction (PCR) assay.

Results: The GAS SIBA assay detected small amounts (ten copies) of S. pyogenes DNA within 13 min. The rapid detection time was achieved in part by optimization of magnesium concentration and reaction temperature. The sensitivity and specificity of the GAS SIBA assay for detection of S. pyogenes from clinical specimens were both 100%, and clinical specimens were detected within ~ 8 min of starting the reaction.

Conclusion: Because the GAS SIBA assay is performed at low and constant temperature, it can be used both in centralized laboratories and for point-of-care testing. Furthermore, given its short detection time and strong analytical performance, the GAS SIBA assay could help to improve patient care and minimize unnecessary prescription of antibiotics.