A comparison of the Quidel Solana GAS assay, the Luminex Aries Group A Strep assay and the Focus Diagnostics Simplexa Group A Strep Direct assay for detection of Group A Streptococcus in throat swab specimens

One of the most common conditions encountered in the out-patient setting is acute pharyngitis. Group A Streptococcus (GAS) accounts for 15%-30% of cases of sore throat particularly in children under 15 years old. Rapid antigen testing (RADT) is an alternative diagnostic method to detect GAS pharyngitis. This study was done to evaluate the agreement between RADT whereby BIONEXIA® Strep A Plus (BioMérieux, France) kit was used and throat culture in the diagnosis of GAS pharyngitis in children presented with a sore throat. One hundred and ten children from a primary health care clinic with sore throat were included in this study. All children were evaluated based on McIsaac scoring and throat swab samples were taken for both throat culture and RADT testing. The prevalence of GAS pharyngitis by RADT in this study was 7.3% over one year. A higher incidence of GAS pharyngitis was noted in the school-aged children than the preschool-age children. There was no correlation between cough, lymph node enlargement, and tonsillar enlargement in predicting GAS pharyngitis. The sensitivity and specificity of RADT were 100% and 98%, respectively, when taking throat culture as a gold standard. A good agreement between RADT and throat culture was achieved (k=0.848). McIsaac scoring was noted to have good predictability for GAS pharyngitis with AUC=0.82. In conclusion, the rapid streptococcal antigen detection test showed excellent sensitivity and specificity and detecting GAS from the throat swab samples. Thus, it can be used to aid in the diagnosis of group A Streptococcal pharyngitis and could reduce the overuse of antibiotics. McIsaac score has also proven to be useful as a screening tool for bacterial pharyngitis.

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Preceding group A streptococcus skin and throat infections are individually associated with acute rheumatic fever: evidence from New Zealand

BMJ Global Health ◽

10.1136/bmjgh-2021-007038 ◽

2021 ◽

Vol 6 (12) ◽

pp. e007038

Author(s):

Jane Oliver ◽

Julie Bennett ◽

Sally Thomas ◽

Jane Zhang ◽

Nevil Pierse ◽

...

Keyword(s):

New Zealand ◽

Rheumatic Fever ◽

Acute Rheumatic Fever ◽

Throat Swab ◽

Group A Streptococcus ◽

Population Level ◽

Gas Detection ◽

Positive Skin ◽

Group A ◽

Dispensing Data

IntroductionAcute rheumatic fever (ARF) is usually considered a consequence of group A streptococcus (GAS) pharyngitis, with GAS skin infections not considered a major trigger. The aim was to quantify the risk of ARF following a GAS-positive skin or throat swab.MethodsThis retrospective analysis used pre-existing administrative data. Throat and skin swab data (1 866 981 swabs) from the Auckland region, New Zealand and antibiotic dispensing data were used (2010–2017). Incident ARF cases were identified using hospitalisation data (2010–2018). The risk ratio (RR) of ARF following swab collection was estimated across selected features and timeframes. Antibiotic dispensing data were linked to investigate whether this altered ARF risk following GAS detection.ResultsARF risk increased following GAS detection in a throat or skin swab. Māori and Pacific Peoples had the highest ARF risk 8–90 days following a GAS-positive throat or skin swab, compared with a GAS-negative swab. During this period, the RR for Māori and Pacific Peoples following a GAS-positive throat swab was 4.8 (95% CI 3.6 to 6.4) and following a GAS-positive skin swab, the RR was 5.1 (95% CI 1.8 to 15.0). Antibiotic dispensing was not associated with a reduction in ARF risk following GAS detection in a throat swab (antibiotics not dispensed (RR: 4.1, 95% CI 2.7 to 6.2), antibiotics dispensed (RR: 4.3, 95% CI 2.5 to 7.4) or in a skin swab (antibiotics not dispensed (RR: 3.5, 95% CI 0.9 to 13.9), antibiotics dispensed (RR: 2.0, 95% CI 0.3 to 12.1).ConclusionsA GAS-positive throat or skin swab is strongly associated with subsequent ARF, particularly for Māori and Pacific Peoples. This study provides the first population-level evidence that GAS skin infection can trigger ARF.

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Multicenter Evaluation of the Solana Group A Streptococcus Assay: Comparison with Culture

Journal of Clinical Microbiology ◽

10.1128/jcm.01268-16 ◽

2016 ◽

Vol 54 (9) ◽

pp. 2388-2390 ◽

Cited By ~ 8

Author(s):

Timothy S. Uphoff ◽

Blake W. Buchan ◽

Nathan A. Ledeboer ◽

Paul A. Granato ◽

Judy A. Daly ◽

...

Keyword(s):

Throat Swab ◽

Group A Streptococcus ◽

Gas Detection ◽

Content Type ◽

Group A

We compared group AStreptococcus(GAS) culture with a rapid helicase-dependent amplification (HDA) method using 1,082 throat swab specimens. The HDA method demonstrated 98.2% sensitivity and 97.2% specificity. GAS prevalence by culture was 20.7%, and it was 22.6% using the HDA method. In 35 min, the HDA method provided rapid, sensitive GAS detection, making culture confirmation unnecessary.

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The feasibility of measuring calprotectin from a throat swab as a marker of infections caused by group A streptococcus: a case–control feasibility study

BJGP Open ◽

10.3399/bjgpopen20x101006 ◽

2020 ◽

Vol 4 (2) ◽

pp. bjgpopen20X101006

Author(s):

Behnaz Schofield ◽

Clive Gregory ◽

Micaela Gal ◽

David Gillespie ◽

Gurudutt Naik ◽

...

Keyword(s):

Primary Care ◽

Healthy Volunteers ◽

Sore Throat ◽

Throat Swab ◽

Group A Streptococcus ◽

Case Control ◽

Antibiotic Prescribing ◽

Group A ◽

Primary Care Patients ◽

Streptococcus A

BackgroundMost people with sore throat do not benefit from antibiotic treatment, but nearly three-quarters of those presenting in primary care are prescribed antibiotics. A test that is predictive of bacterial infection could help guide antibiotic prescribing. Calprotectin is a biomarker of neutrophilic inflammation, and may be a useful marker of bacterial throat infections.AimTo assess the feasibility of measuring calprotectin from throat swabs, and assess whether individuals with sore throats likely to be caused by streptococcal infections have apparently higher throat calprotectin levels than other individuals with sore throat and healthy volunteers.Design & settingA proof of concept case–control study was undertaken, which compared primary care patients with sore throats and healthy volunteers.MethodBaseline characteristics and throat swabs were collected from 30 primary care patients with suspected streptococcal sore throat, and throat swabs were taken from 10 volunteers without sore throat. Calprotectin level determination and rapid antigen streptococcal testing were conducted on the throat swab eluents. Calprotectin levels in the following groups were compared: volunteers without a sore throat; all patients with a sore throat; patients with a sore throat testing either negative or positive for streptococcal antigen; and those with lower and higher scores on clinical prediction rules for streptococcal sore throat.ResultsCalprotectin was detected in all throat swab samples. Mean calprotectin levels were numerically higher in patients with sore throat compared with healthy volunteers, and sore throat patients who had group A streptococci antigen detected compared with those who did not.ConclusionCalprotectin can be measured from throat swab samples and levels are consistent with the hypothesis that streptococcal infection leads to higher throat calprotectin levels. This hypothesis will be tested in a larger study.

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Group A streptococcal pharyngitis: A practical guide to diagnosis and treatment

Paediatrics & Child Health ◽

10.1093/pch/pxab025 ◽

2021 ◽

Vol 26 (5) ◽

pp. 319-319

Author(s):

Laura Sauve ◽

A Michael Forrester ◽

Karina A Top

Keyword(s):

Primary Care ◽

Acute Rheumatic Fever ◽

Throat Swab ◽

Group A Streptococcus ◽

Streptococcal Pharyngitis ◽

Clinical Syndrome ◽

Indigenous Populations ◽

Diagnosis And Treatment ◽

Group A ◽

Disproportionate Burden

Abstract Group A Streptococcus (GAS) pharyngitis is a common clinical syndrome in primary care, yet controversy remains regarding the best approach to diagnosis and treatment, including the benefits of antibiotics. Children who are likely to have GAS pharyngitis based on history or physical examination should have a throat swab and, when positive, be treated with amoxicillin or penicillin. The disproportionate burden of acute rheumatic fever in Indigenous populations in Canada and special considerations for testing and treatment are discussed.

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