Efficient detection of Streptococcus pyogenes based on recombinase polymerase amplification and lateral flow strip.

Purpose: This article aims to establish a rapid visual method for the detection of Streptococcus pyogenes (GAS) based on recombinase polymerase amplification (RPA) and lateral flow strip (LFS).

Methods: Utilizing speB of GAS as a template, RPA primers were designed, and basic RPA reactions were performed. To reduce the formation of primer dimers, base mismatch was introduced into primers. The probe was designed according to the forward primer, and the RPA-LFS system was established. According to the color results of the reaction system, the optimum reaction temperature and time were determined. Thirteen common clinical standard strains and 14 clinical samples of GAS were used to detect the selectivity of this method. The detection limit of this method was detected by using tenfold gradient dilution of GAS genome as template. One hundred fifty-six clinical samples were collected and compared with qPCR method and culture method. Kappa index and clinical application evaluation of the RPA-LFS were carried out.

Results: The enhanced RPA-LFS method demonstrates the ability to complete the amplification process within 6 min at 33 °C. This method exhibits a high analytic sensitivity, with the lowest detection limit of 0.908 ng, and does not exhibit cross-reaction with other pathogenic bacteria.

Conclusions: The utilization of RPA and LFS allows for efficient and rapid testing of GAS, thereby serving as a valuable method for point-of-care testing.