Development of a lateral flow immunoassay using antibody cocktail for the detection of the various epidemic subtypes of group A Streptococcus in clinical samples

Abstract

Group A Streptococcus (GAS), a major pathogen, causes various respiratory diseases with substantial morbidity and mortality worldwide. In this study, we develop an immunoassay for the early screening and diagnosis of GAS infections. A latex beads-based lateral flow immunoassay (LBs-LFIA) and a fluorescent beads-based LFIA (FBs-LFIA) using an antibody cocktail that was coated on the test line (T line), the limit of detection (LoD) of LBs-LFIA was 105 CFU mL−1 and FBs-LFIA was 103 CFU mL−1. Furthermore, the use of the antibody cocktail led to the detection of the various epidemic clinical types of GAS with high sensitivity (100%) and specificity (＞95%). To devise a point-of-care testing (POCT) platform for mass screening in low-resource areas, a mobile phone-based portable strip reader capable of visually interpreting the results was developed and the LoD of LBs-LFIA and FBs-LFIA were calculated as 104 CFU mL−1 and 102 CFU mL−1, respectively. Taken together, we suggest that the developed LBs-LFIA and FBs-LFIA using the antibody cocktail can be used for the clinical emergency detection of GAS infections.