Diagnosis of Group A Streptococcus (GAS) pharyngitis in children is hindered by variable sensitivity of clinical criteria and rapid Strep A tests (SAT), resulting in reliance on throat cultures as the gold standard for diagnosis. Delays while awaiting culture reports result in unnecessary antibiotic prescriptions among children, contributing to the spread of antimicrobial resistance (AMR).
Diagnostic accuracy study of an automated SAT (A-SAT) in children up to 16 years of age presenting to an emergency room with signs and symptoms of pharyngitis between March and June 2019. Paired throat swabs for A-SAT and culture were collected. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for A-SAT were calculated.
Two hundred and ninety-one children were included in this study. 168 (57.7%) were boys and the mean age was 4.2 years. A-SAT was positive in 94 (32.3%) and throat culture was positive in 90 (30.9%) children. A-SAT and throat culture results showed a high level of consistency in our cohort. Only 6 (2%) children had inconsistent results, demonstrating that the A-SAT has a high sensitivity (98.9%), specificity (97.5%), PPV (94.7%) and NPV (99.5%) for the diagnosis of GAS pharyngitis in children. Only 92 (32%) children were prescribed antibiotics while the vast majority (68%) were not.
A-SAT is a quick and reliable test with diagnostic accuracy comparable to throat culture. Its widespread clinical use can help limit antibiotic prescriptions to children presenting with pharyngitis, thus limiting the spread of AMR.

Although most cases of acute pharyngitis are viral in origin, antibiotics are overused in its treatment. Streptococcus pyogenes (group A streptococcus, GAS), the principal bacterial pathogen of acute sore throat, is responsible for merely 5-30% of cases. Moreover, GAS pharyngitis is currently the only commonly occurring form of acute pharyngitis for which antibiotic therapy is definitely indicated. Therefore the differentiation between GAS pharyngitis and that of viral etiology is crucial. Accordingly, scientific societies as well as respected advisory bodies in Europe and North America, issued guidelines for the management of acute pharyngitis with the aim of minimizing unnecessary antibiotic prescriptions in its treatment. The aim of this review work is to confront the state of the art in acute GAS pharyngitis diagnosis and treatment with different approaches to its management represented by current European and North American guidelines. Although based on scientific evidence, international guidelines differ substantially in opinions whether GAS pharyngitis diagnosis should be based on microbiological testing, clinical algorithm or a combination of both. On the other hand, some European guidelines consider GAS pharyngitis to be a mild, self-limiting disease that does not require a specific diagnosis or antimicrobial treatment except in high-risk patients. There is an agreement among guidelines that if antibiotic therapy is indicated, phenoxymethyl penicillin should be the drug of choice to treat GAS pharyngitis.

BACKGROUND: The diagnosis of streptococcal pharyngitis is very important to prevent complications such as acute rheumatic fever. Throat culture is the gold standard method for the diagnosis of streptococcal pharyngitis, however, rapid antigen tests (RAT) have been developed for faster diagnosis. The purpose of this study is to evaluate the efficacy of the BD Veritor ™ System (USA) rapid antigen assay in detecting Group A Streptococcus (GAS) in throat swab samples.
METHODS: A total of 12,391 throat swabs, taken with a double swab, were evaluated. The BD Veritor ™ System was used for the detection of GAS antigen. Simultaneous throat cultures were performed.
RESULTS: Throat culture yielded positive for 18.5% (2291) while 19.1% (2369) were positive with RAT. The sensitivity of BD Veritor ™ System was determined as 94.1% and specificity as 97.9%, while positive predictive value, negative predictive value and accuracy were determined as 91.0%, 98.7%, 97%, respectively. When all age groups were included, the rate of GAS positivity was 18.5% and this ratio increased to 27.3% in the five-15 age group.
CONCLUSIONS: Our study, conducted with quite a large number of patients, yielded high sensitivity for the BD Veritor System. When the RAT is negative, the necessity of culture for pediatric patients should not be forgotten.

OBJECTIVE: The aim of our study was to determine the usefulness of the Centor score and some basic laboratory tests (complete blood count and C-reactive protein) for the differential diagnosis of exudative tonsillitis due to Group A β-hemolytic streptococcus (GABHS) or due to non-GABHS agents.
METHODS: The data of clinical and laboratory characteristics of the patients diagnosed with exudative tonsillitis were collected and statistically compared between those having positive GABHS throat culture result and those who were negative for any bacterial agent.
RESULTS: Totally 899 adult patients were included in our study; 56 (6.2%) of them were positive for GABHS, while 34 (3.8%) of the cases had a bacterial cause other than GABHS. The remaining 809 (90%) were accepted as non-GABHS cases. The percentages of patients having Centor score of 3 or greater, neutrophilia, lymphocytopenia, and CRP values of greater than 5-fold normal upper reference range were significantly higher in GABHS patients.
CONCLUSIONS: Centor score of 3 or more together with high CRP, neutrophilia, and lymphocytopenia is predictive for GABHS tonsillopharyngitis.

We aimed to investigate the effect of rapid antigen detection test (RADT) in the diagnosis of streptococcal pharyngitis, its impact on antibiotic prescription decision of pediatricians and influence on reduction of antibiotic treatment costs in children with pharyngitis. The study group consisted of 223 patients who were diagnosed with pharyngitis by pediatricians. The sensitivity and specificity of RADT were 92.1% (95% Cl: 78.6-98.3%) and 97.3% (95% Cl: 93.8-99.1%), respectively. In the first assessment, before performing RADT, pediatricians decided to prescribe antibiotics for 178 (79.8%) patients with pharyngitis. After learning RADT results, pediatricians finally decided to prescribe antibiotics for 83 (37.2%) patients with pharyngitis, and antibiotic prescription decreased by 42.6%. Antibiotic costs in non-Group A streptococcus pharyngitis, Group A streptococcus pharyngitis and all subjects groups decreased by 80.8%, 48%, and 76.4%, respectively. Performing RADT in children with pharyngitis has an important impact on treatment decision of clinicians, reduction of unnecessary antibiotic prescriptions and antibiotic costs.

OBJECTIVE: Group A Streptococcus (GAS) pharyngitis is currently the only commonly occurring form of acute pharyngitis for which antibiotic therapy is definitely indicated. Polish guidelines advocate the use of modified Centor score (MCS) to assess the probability of GAS pharyngitis. They advise performing throat culture or rapid antigen detection test (RADT) in children with score 2-3 in MCS and treating with antibiotic only those in whom GAS was detected. Negative RADT results should be confirmed by culture. In children with score 4, the guidelines allow to introduce empiric antibiotic therapy. Phenoxymethyl penicillin is recommended as a drug of choice to treat GAS pharyngitis. The aim of our study was to evaluate the accuracy of strategy recommended by Polish guidelines in identifying those children with acute pharyngitis who require antibiotic treatment. Hence, diagnostic values of score 4 in MCS and RADT were assessed using throat culture as a reference standard. Phenoxymethyl penicillin efficacy in GAS eradication and prevention of post-streptococcal complications were estimated as well.
METHODS: Ninety children between 2 and 15 years of age with acute pharyngitis symptoms suggesting GAS etiology (MCS ≥ 2), participated in our study. At the initial visit MCS was evaluated and two throat swabs were collected to perform RADT and culture. In children with GAS pharyngitis treated with penicillin, microbiological cure was assessed by performing two control throat cultures. Next, children were under observation for 3 months.
RESULTS: Positive predictive value of score 4 in MCS turned out to be 48.05% (95% CI: 36.5-59.7%). RADT sensitivity, specificity and diagnostic accuracy proved to be 100%, 96%, and 98%, respectively. GAS eradication rate in children treated with penicillin turned out to be 92.5%. No post-streptococcal sequelae occurred in any child in 3-month observation.
CONCLUSIONS: Empiric antibiotic therapy in children with score 4 in MCS will result in significant overtreatment of those with nonstreptococcal pharyngitis. New generation RADT diagnostic value in GAS detection proved to be equivalent to that of culture, which obviates the need of backup culture in children with negative RADT results. Phenoxymethyl penicillin revealed high eradication efficacy and proved to prevent post-streptococcal sequelae in children with acute GAS pharyngitis.