Group A Streptococcus Testing in Pediatrics: the Move to Point-of-Care Molecular Testing

Abstract

Each year, there are an estimated 11 million visits to ambulatory care centers for pharyngitis in children between the ages of 3 and 18 years. While there are many causes of pediatric pharyngitis, group A streptococcal pharyngitis represents 15 to 30% of infections and is the only cause for which treatment is recommended. Unfortunately, clinical suspicion is insufficient for the accurate diagnosis of group A streptococcal pharyngitis, and laboratory testing for confirmation of Streptococcus pyogenes infection is required to prevent complications of infection. Traditionally, throat swabs are inoculated onto agar plates for isolation of the large-zone beta-hemolytic streptococcus. However, traditional culture methods present a potential delay in treatment due to turnaround times of 18 to 48 h. In order to improve turnaround times and enhance antimicrobial stewardship, multiple point-of-care assays have been developed. This review describes current point-of-care testing for group A streptococcal pharyngitis, including rapid antigen detection tests and more recent molecular methods. Additional attention is given to the diagnostic considerations when choosing a method for group A streptococcal point-of-care testing, implementation of molecular group A streptococcal testing, and the institutional cost of immunoassays compared to those of newer molecular methods.

Recent Advances in the Rheumatic Fever and Rheumatic Heart Disease Continuum

“…More recent progress in the area of point-of-care tests for GAS pharyngitis include Nucleic Acid Amplification Tests (NAATs), which have much better sensitivity and specificity than RADTs [135]. For example, the sensitivity and specificity of the Illumigene assay are estimated to be in excess of 99% [135][136][137]. This high performance, coupled with speed of results, makes NAATs ideal candidates for point-of-care use in the clinical environment.…”

Nanobiosensor Based on Sugar Code-AuNPs Aggregation: A Key to Opening New Gates in Rapid Diagnosis of Streptococcal Pharyngitis

“…The comparison of H-1-AuNPs with previously reported biosensors for detection of GAS is presented in Table 1. Although, the commercially available products (US FDA approved) such as Sofia, BD Veritor, and ID NOW can help in the accurate diagnosis of streptococcal pharyngitis (Bulut et al, 2020;Thompson and McMullen, 2020; Quidel Corporation 2015; U.S. Food and Drug Administration 2013; U.S. Food and Drug Administration 2018; Abbott Diagnostics Scarborough 2020), they are not widely used by clinicians worldwide, mainly because of their high price. Besides, the functionality of these products is dependent on the instrument, making them difficult to use.…”

“…Sofia and BD Veritor are based on antibody-antigen interaction, and ID NOW is based on isothermal nucleic acid amplification technology. Owing to their high specificity and sensitivity, these products can help in the accurate diagnosis of streptococcal pharyngitis (Bulut et al, 2020;Thompson and McMullen, 2020;Quidel Corporation 2015; U.S. Food and Drug Administration 2013; U.S. Food and Drug Administration 2018; Abbott Diagnostics Scarborough 2020). Nevertheless, they are not widely used by clinicians worldwide, which may be in terms of their high price and dependence on the instrument.…”

Single-centre, open-label, randomised, trial to compare rapid molecular point-of-care streptococcal testing to standard laboratory-based testing for the management of streptococcal pharyngitis in children: study protocol

“…18 The Abbott ID NOW Strep A2, approved by Health Canada for the detection of GAS in pharyngeal swabs, has been found to have a sensitivity of 98.5% (and a specificity of at least 93.4%) as compared with culture, 17 19 20 a positive result is signalled in ~3 min, and a negative result requires only 6 min to document, which is 10–15 min quicker than some of its competitors. 21 …”

“…18 The Abbott ID NOW Strep A2, approved by Health Canada for the detection of GAS in pharyngeal swabs, has been found to have a sensitivity of 98.5% (and a specificity of at least 93.4%) as compared with culture, 17 19 20 a positive result is signalled in ~3 min, and a negative result requires only 6 min to document, which is 10-15 min quicker than some of its competitors. 21 The reference standard for GAS diagnosis has long been bacterial culture; classically, throat swabs are plated on sheep blood agar and incubated at 37°C for 18-24 hours. 1 21 Participants randomised to the control arm will have swabs processed for culture using the bioMérieux Walk Away Specimen Processor in the bacteriology laboratory.…”