Management of adults with acute streptococcal pharyngitis: minimal value for backup strep testing and overuse of antibiotics

Antibiotic consumption for sore throat and the potential effect of a vaccine against group A Streptococcus: a systematic review and modelling study

BACKGROUND

Antibiotic consumption can lead to antimicrobial resistance and microbiome imbalance. We sought to estimate global antibiotic consumption for sore throat, and the potential reduction in consumption due to effective vaccination against group A Streptococcus (Strep A).

METHODS

We reviewed and analysed articles published between January 2000 and February 2022, identified though Clarivate Analytics' Web of Science search platform, with reference to antibiotic prescribing or consumption, sore throat, pharyngitis, or tonsillitis. We then used those analyses, combined with assumptions for the effectiveness, duration of protection, and coverage of a vaccine, to calculate the estimated reduction in antibiotic prescribing due to the introduction of Strep A vaccines.

FINDINGS

We identified 101 studies covering 38 countries. The mean prescribing rate for sore throat was approximately 5 courses per 100 population per year, accounting for approximately 5% of all antibiotic consumption. Based on 2020 population estimates for countries with empiric prescribing rates, antibiotic consumption for sore throat was estimated to exceed 37 million courses annually, of which half could be attributable to treatment for Strep A. A vaccine that reduces rates of Strep A infection by 80%, with 80% coverage and 10 year's duration of protection, could avert 2.8 million courses of antibiotics prescribed for sore throat treatment among 5-14 year-olds in countries with observed prescribing rates, increasing to an estimated 7.5 million averted if an effective vaccination program also reduced precautionary prescribing.

INTERPRETATION

A vaccine that prevents Strep A throat infections in children may reduce antibiotic prescribing for sore throat by 32-87% depending on changes to prescribing and consumption behaviours.

FUNDING

The Wellcome Trust, grant agreement number 215490/Z/19/Z.

Modalities of group A streptococcal prevention and treatment and their economic justification

Infection by group A Streptococcus (Strep A) results in a diverse range of clinical conditions, including pharyngitis, impetigo, cellulitis, necrotising fasciitis, and rheumatic heart disease. In this article, we outline the recommended strategies for Strep A treatment and prevention and review the literature for economic evaluations of competing treatment and prevention strategies. We find that most economic evaluations focus on reducing the duration of illness or risk of rheumatic fever among people presenting with sore throat through diagnostic and/or treatment strategies. Few studies have evaluated strategies to reduce the burden of Strep A infection among the general population, nor have they considered the local capacity to finance and implement strategies. Evaluation of validated costs and consequences for a more diverse range of Strep A interventions are needed to ensure policies maximise patient outcomes under budget constraints. This should include attention to basic public health strategies and emerging strategies such as vaccination.

The Impact of Point-of-Care Polymerase Chain Reaction Testing on Prescribing Practices in Primary Care for Management of Strep A: A Retrospective Before-After Study

Background

Rapid antigen detection tests (RADTs) are the standard of care (SOC) for testing in patients with suspected group A β-hemolytic Streptococcus (Strep A) infection. Due to lower sensitivity, guidelines recommend confirmatory microbiological culture following negative RADT results. This process is time-consuming, and adherence is often poor, resulting in high rates of inappropriate antibiotic prescribing. We sought to evaluate the impact of switching from RADTs to point-of-care (POC) polymerase chain reaction (PCR) testing on use of antibiotics in primary care, when used as part of an antibiotic stewardship initiative.

Methods

In this retrospective before-after study, electronic medical records of any patients presenting with suspected acute pharyngitis (June 2018-May 2019) across 15 outpatient primary care clinics were evaluated. Strep A was detected using the cobas Strep A assay (cobas Liat system).

Results

Analysis of 10 081 eligible patient records showed that POC PCR testing resulted in a 44.1% reduction in antibiotic prescribing for patients with a negative POC PCR test result (10.1% PCR vs 18.0% RADT; P < .0001). Rates of antibiotic prescription varied across clinical sites, ranging between 10.7% and 33.8% and 12.4% and 34.4% during the use of PCR tests and RADTs, respectively. POC PCR had no impact on prescription rates in patients with positive POC test results compared to RADTs (76.2% vs 76.5%, respectively). More than 99% of antibiotics were prescribed during the initial primary care encounter.

Conclusions

As part of a broader antibiotic stewardship initiative, implementation of POC PCR as SOC in outpatients with acute pharyngitis symptoms reduced the volume of inappropriate antibiotic prescriptions.

Age and sex-specific incidence rates of group A streptococcal pharyngitis between 2010 and 2018: a population-based study

Aim: Group A streptococcus (GAS) pharyngitis is a common clinical infection with significant morbidity but remains understudied. Materials & methods: We sought to assess the rates of testing and incidence of GAS pharyngitis in Calgary, Alberta based on age and sex. Results: A total of 1,074,154 tests were analyzed (58.8% female, mean age 24.8 years) of which 16.6% were positive. Age-standardized testing and positivity was greatest in the 5-14 years age group and lowest in persons over 75 years. Females had greater rates of testing and positivity throughout. Testing rates (incidence rate ratios: 1.40, 95% CI: 1.39-1.41) and case rates (incidence rate ratios: 1.36, 95% CI: 1.33-1.39) increased over time. Conclusion: Future studies should focus on evaluating disparities in testing and treatment outcomes to optimize the approach to this infection.

Diagnostic Methods, Clinical Guidelines, and Antibiotic Treatment for Group A Streptococcal Pharyngitis: A Narrative Review

The most common bacterial cause of pharyngitis is infection by Group A β-hemolytic streptococcus (GABHS), commonly known as strep throat. 5-15% of adults and 15-35% of children in the United States with pharyngitis have a GABHS infection. The symptoms of GABHS overlap with non-GABHS and viral causes of acute pharyngitis, complicating the problem of diagnosis. A careful physical examination and patient history is the starting point for diagnosing GABHS. After a physical examination and patient history is completed, five types of diagnostic methods can be used to ascertain the presence of a GABHS infection: clinical scoring systems, rapid antigen detection tests, throat culture, nucleic acid amplification tests, and machine learning and artificial intelligence. Clinical guidelines developed by professional associations can help medical professionals choose among available techniques to diagnose strep throat. However, guidelines for diagnosing GABHS created by the American and European professional associations vary significantly, and there is substantial evidence that most physicians do not follow any published guidelines. Treatment for GABHS using analgesics, antipyretics, and antibiotics seeks to provide symptom relief, shorten the duration of illness, prevent nonsuppurative and suppurative complications, and decrease the risk of contagion, while minimizing the unnecessary use of antibiotics. There is broad agreement that antibiotics with narrow spectrums of activity are appropriate for treating strep throat. But whether and when patients should be treated with antibiotics for GABHS remains a controversial question. There is no clearly superior management strategy for strep throat, as significant controversy exists regarding the best methods to diagnose GABHS and under what conditions antibiotics should be prescribed.

Pharyngitis: Approach to diagnosis and treatment

OBJECTIVE

To provide family physicians with an updated approach to diagnosis and treatment of pharyngitis, detailing key symptoms, methods of investigation, and a summary of common causes.

SOURCES OF INFORMATION

The approach described is based on the authors' clinical practice and peer-reviewed literature from 1989 to 2018.

MAIN MESSAGE

Sore throat caused by pharyngitis is commonly seen in family medicine clinics and is caused by inflammation of the pharynx and surrounding tissues. Pharyngitis can be caused by viral, bacterial, or fungal infections. Viral causes are often self-limiting, while bacterial and fungal infections typically require antimicrobial therapy. Rapid antigen detection tests and throat cultures can be used with clinical findings to identify the inciting organism. Pharyngitis caused by Streptococcus pyogenes is among the most concerning owing to its associated severe complications such as acute rheumatic fever and glomerulonephritis. Hence, careful diagnosis of pharyngitis is necessary to provide targeted treatment.

CONCLUSION

A thorough history is key to diagnosing pharyngitis. Rapid antigen detection tests should be reserved for concerns about antibiotic initiation. Physicians should exercise restraint in antibiotic initiation for pharyngitis, as restraint does not delay recovery or increase the risk of S pyogenes infections.

[Not Available]

Objectif

Offrir aux médecins de famille une approche diagnostique et thérapeutique actualisée de la pharyngite, en décrivant en détail les principaux symptômes, les méthodes d’investigation et un résumé des causes courantes.

Sources d’information

L’approche décrite est basée sur la pratique clinique des auteurs et sur les publications revues par les pairs de 1989 à 2018.

Message principal

Le mal de gorge causé par la pharyngite est couramment observé dans les cliniques de médecine familiale; il est causé par l’inflammation du pharynx et des tissus environnants. La pharyngite est causée par une infection virale, bactérienne ou fongique. Les causes virales sont souvent spontanément résolutives, alors que les infections bactériennes et fongiques nécessitent habituellement l’antibiothérapie. Le test de détection rapide de l’antigène et la culture de gorge sont jumelés aux observations cliniques pour identifier l’organisme en cause. La pharyngite causée par streptococcus pyogenes fait partie des organismes les plus préoccupants en raison de ses complications graves, telles la fièvre rhumatismale aiguë et la glomérulonéphrite. Ainsi, il est nécessaire de poser un diagnostic attentif de pharyngite afin de pouvoir dispenser un traitement ciblé.

Conclusion

L’anamnèse détaillée est la clé du diagnostic de pharyngite. Le test de détection rapide de l’antigène doit être réservé aux cas où l’instauration de l’antibiothérapie est préoccupante. Les médecins doivent user de retenue lorsqu’ils instaurent l’antibiothérapie contre la pharyngite, puisque la retenue ne retarde pas le rétablissement ni n’augmente le risque d’infection à s. pyogenes.

Diagnosis and Management of Group a Streptococcal Pharyngitis in the United States, 2011-2015

Background

Clinical guidelines for the diagnosis of group A streptococcal (GAS) pharyngitis recommend the use of a rapid antigen detection test (RADT) and/or bacterial culture. This study evaluated the overall diagnosis and treatment of acute pharyngitis in the United States, including predictors of test type and antibiotic prescription.

Methods

A retrospective analysis of pharyngitis events from 2011 through 2015 was conducted using the MarketScan commercial/Medicare databases. A pharyngitis event was defined as occurring within 2 weeks from the index visit. Patient and provider characteristics were examined across 5 testing categories: RADT, RADT plus culture, other tests, nucleic acid amplification testing (NAAT), and no test. Multivariate models were used to identify significant predictors of NAAT use and antibiotic prescription.

Results

A total of 18.8 million acute pharyngitis events were identified in 11.6 million patients. Roughly two-thirds of events (68.2%) occurred once, and roughly a third of patients (29.1%) required additional follow-up, but hospitalization was rare (0.3%). Across all events, 43% were diagnosed by RADT, while 20% were diagnosed by RADT plus culture. The proportion of events diagnosed by NAAT increased 3.5-fold from 2011 to 2015 (0.06% vs 0.27%). Antibiotic use was frequent (49.3%), less often in combination with RADT plus culture (31.2%) or NAAT alone (34.5%) but significantly more often with RADT alone (53.4%) or no test (57.1%). Pediatricians were significantly less likely than other providers to prescribe antibiotics in their patients, regardless of patient age (p < 0.0001).

Conclusions

Antibiotic use for sore throat remains common, with many clinicians not following current guidelines for diagnosis of GAS pharyngitis. Diagnosis of GAS pharyngitis using RADT plus culture or NAAT alone was associated with lower use of antibiotics. Diagnostic testing can help lower the incidence of inappropriate antibiotic use, and inclusion of NAAT in the clinical guidelines for GAS pharyngitis warrants consideration.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3835-4) contains supplementary material, which is available to authorized users.

Association between rapid antigen detection tests and antibiotics for acute pharyngitis in Japan: A retrospective observational study

The application and clinical impact of rapid antigen detection test (RADT) in the treatment of acute pharyngitis is unknown in Japan. We aimed to examine the proportions of RADT usage to identify Group A β-hemolytic Streptococcus (GAS) in outpatients with acute pharyngitis and evaluate the association between RADT and antibiotic treatment. We analyzed health insurance claims data from 2013 to 2015. Logistic regression models were used to analyze associated factors with RADT, overall antibiotic prescription, or penicillin use. We analyzed 1.27 million outpatient visits with acute pharyngitis, in which antibiotics were prescribed in 59.3% of visits. Of the total visits, 5.6% of patients received RADT, and 10.8% of the antibiotics were penicillin. Penicillin selection rates were higher in cases with RADT (25.4%) than those without RADT (9.7%). Compared to large-scale facilities, antibiotic prescription rates were higher in physicians' offices. For factor analysis, age (3-15 years), diagnosis code (streptococcal pharyngitis), size of the medical facility (large-scale hospitals), and physician's specialty (pediatrics) were associated with RADT use. Penicillin selection rate increased with RADT implementation (25.4% vs. 9.7%: adjusted odds ratio 1.55; 95% CI, 1.50-1.60). At 63% of the facilities, the RADT implementation rate was <5% of acute pharyngitis visits prescribed antibiotics. In conclusion, the proportion of RADT usage for outpatients with acute pharyngitis was low in Japan. With appropriate indication and evaluation, we expect that more utilization of RADT can help promote antimicrobial stewardship for outpatients with acute pharyngitis by prompting penicillin therapy. Further investigation with detailed clinical data are warranted.

Clinical Impact of a Rapid Streptococcal Antigen Test on Antibiotic Use in Adult Patients

INTRODUCTION

Adult pharyngitis is rarely attributable to group A streptococci. Utilization of a rapid streptococcal antigen test (RADT) may improve appropriate prescribing for bacterial pharyngitis.

METHODS

Clinic 1 performed RADTs with subsequent Group A DNA probe test (GADNA) from November 2014-March 2015 and November 2015-March 2016 while Clinic 2 was the control clinic, then implemented the RADT with a GADNA from November 2015-March 2016. All GADNA results were obtained for each clinic from October 2013-March 2016.

RESULTS

At Clinic 1, 22.2% versus 8.5% of patients received inappropriately prescribed antibiotics for a GADNA or RADT result, respectively (p=0.048). For Clinic 2, 51.1% compared to 21.4% of patients were inappropriately prescribed antibiotic for a GADNA or RADT result, respectively (p=0.038). Overall, the total GADNA without RADT testing or RADTs with subsequent GADNA testing, 41.6% versus 11% of patients were inappropriately prescribed antibiotics, respectively (p=<0.0001).

CONCLUSION

Utilizing the RADT prevented unnecessary prescribing of antibiotics in adults.

Clinical Mimics: An Emergency Medicine-Focused Review of Streptococcal Pharyngitis Mimics

BACKGROUND

Pharyngitis is a common disease in the emergency department (ED). Despite a relatively low incidence of complications, there are many dangerous conditions that can mimic this disease and are essential for the emergency physician to consider.

OBJECTIVE

This article provides a review of the evaluation and management of group A β-hemolytic Streptococcal (GABHS) pharyngitis, as well as important medical conditions that can mimic this disease.

DISCUSSION

GABHS pharyngitis often presents with fever, sore throat, tonsillar exudates, and anterior cervical lymphadenopathy. History and physical examination are insufficient for the diagnosis. The Centor criteria or McIsaac score can help risk stratify patients for subsequent testing or treatment. Antibiotics may reduce symptom duration and suppurative complications, but the effect is small. Rheumatic fever is uncommon in developed countries, and shared decision making is recommended if antibiotics are used for this indication. Oral analgesics and topical anesthetics are important for symptom management. Physicians should consider alternate diagnoses that may mimic GABHS pharyngitis, which can include epiglottitis, infectious mononucleosis, Kawasaki disease, acute retroviral syndrome, Lemierre's syndrome, Ludwig's angina, peritonsillar abscess, retropharyngeal abscess, and viral pharyngitis. A focused history and physical examination can help differentiate these conditions.

CONCLUSIONS

GABHS may present similarly to other benign and potentially deadly diseases. Diagnosis and treatment of pharyngitis should be based on clinical evaluation. Consideration of pharyngitis mimics is important in the evaluation and management of ED patients.

Peritonsillar abscess (PTA): clinical characteristics, microbiology, drug exposures and outcomes of a large multicenter cohort survey of 412 patients hospitalized in 13 French university hospitals

The aim of this study was to describe the epidemiology of hospitalized patients with peritonsillar abscess (PTA). We conducted a multicenter survey in 13 French university hospitals in 2009-2012 describing 412 patients. Median age was 29 year (range, 2-84) and current smoking habit was reported by 177 (43 %) patients. Most of the patients (92 %) had consulted a physician for sore throat within 10 days before admission for PTA diagnosis. Additional symptoms such as visible tonsil abnormalities (83 %), tender cervical adenopathy (57 %) and fever ≥ 38.5 °C (53 %) were also reported. A total of 65 % patients (269/412) reported recent systemic anti-inflammatory agents (AIAs) exposure by medical prescription (70 %), self-medication (22 %), or both (8 %); 61 % and 27 % reported recent exposure to antibiotic and topical treatments for sore throat, respectively. Non-steroidal AIAs were used most often (45 %), particularly arylpropionic derivatives. A rapid diagnosis antigen test (RDT) for Streptococcus pyogenes was performed in 70 (17 %) patients and was positive in 17 (24 %), of whom 9 (53 %) were exposed to AIAs and 14 (82 %) to antibiotics. To treat PTA, antibiotic therapy was given to 392 (95 %) patients. Of 333 antibiotic prescriptions, amoxicillin-clavulanic acid and metronidazole were the most prescribed antibiotics (42 and 17 %, respectively). Surgical drainage of the abscess was performed in 119 (29 %) cases and tonsillectomy in 75 (18 %) cases. The clinical outcome was favorable during the hospital stay in 404 (98 %) patients. In conclusion, patients with sore throat are often exposed to AIAs before PTA diagnosis, and antibiotic prescription was not often based on the RDT positivity.

Usefulness of Leukocyte Esterase Test Versus Rapid Strep Test for Diagnosis of Acute Strep Pharyngitis

OBJECTIVE

A study to compare the usage of throat swab testing for leukocyte esterase on a test strip(urine dip stick-multi stick) to rapid strep test for rapid diagnosis of Group A Beta hemolytic streptococci in cases of acute pharyngitis in children.

HYPOTHESIS

The testing of throat swab for leukocyte esterase on test strip currently used for urine testing may be used to detect throat infection and might be as useful as rapid strep.

METHODS

All patients who come with a complaint of sore throat and fever were examined clinically for erythema of pharynx, tonsils and also for any exudates. Informed consent was obtained from the parents and assent from the subjects. 3 swabs were taken from pharyngo-tonsillar region, testing for culture, rapid strep & Leukocyte Esterase.

RESULTS

Total number is 100. Cultures 9(+); for rapid strep== 84(-) and16 (+); For LE== 80(-) and 20(+)

STATISTICS

From data configuration Rapid Strep versus LE test don't seem to be a random (independent) assignment but extremely aligned. The Statistical results show rapid and LE show very agreeable results. Calculated Value of Chi Squared Exceeds Tabulated under 1 Degree Of Freedom (P<.0.0001) reject Null HYPOTHESIS and Conclude Alternative Conclusions: Leukocyte esterase on throat swab is as useful as rapid strep test for rapid diagnosis of strep pharyngitis on test strip currently used for urine dip stick causing acute pharyngitis in children.

An initiative to improve adherence to evidence-based guidelines in the treatment of URIs, sinusitis, and pharyngitis

Background

Upper respiratory infections, acute sinus infections, and sore throats are common symptoms that cause patients to seek medical care. Despite well-established treatment guidelines, studies indicate that antibiotics are prescribed far more frequently than appropriate, raising a multitude of clinical issues.

Methods

The primary goal of this study was to increase guideline adherence rates for acute sinusitis, pharyngitis, and upper respiratory tract infections (URIs). This study was the first Plan-Do-Study-Act (PDSA) cycle in a quality improvement program at an internal medicine resident faculty practice at a university-affiliated community hospital internal medicine residency program. To improve guideline adherence for respiratory infections, a package of small-scale interventions was implemented aimed at improving patient and provider education regarding viral and bacterial infections and the necessity for antibiotics. The data from this study was compared with a previously published study in this practice, which evaluated the adherence rates for the treatment guidelines before the changes, to determine effectiveness of the modifications. After the first PDSA cycle, providers were surveyed to determine barriers to adherence to antibiotic prescribing guidelines.

Results

After the interventions, antibiotic guideline adherence for URI improved from a rate of 79.28 to 88.58% with a p-value of 0.004. The increase of adherence rates for sinusitis and pharyngitis were 41.7–57.58% (p=0.086) and 24.0–25.0% (p=0.918), respectively. The overall change in guideline adherence for the three conditions increased from 57.2 to 78.6% with the implementations (p<0.001). In planning for future PDSA cycles, a fishbone diagram was constructed in order to identify all perceived facets of the problem of non-adherence to the treatment guidelines for URIs, sinusitis, and pharyngitis. From the fishbone diagram and the provider survey, several potential directions for future work are discussed.

Conclusions

Passive interventions can result in small changes in antibiotic guideline adherence, but further PDSA cycles using more active methodologies are needed.

Participatory medicine: A home score for streptococcal pharyngitis enabled by real-time biosurveillance: a cohort study

BACKGROUND

Consensus guidelines recommend against testing or treating adults at low risk for group A streptococcal (GAS) pharyngitis.

OBJECTIVE

To help patients decide when to visit a clinician for the evaluation of sore throat.

DESIGN

Retrospective cohort study.

SETTING

A national chain of retail health clinics.

PATIENTS

71 776 patients aged 15 years or older with pharyngitis who visited a clinic from September 2006 to December 2008.

MEASUREMENTS

The authors created a score using information from patient-reported clinical variables plus the incidence of local disease and compared it with the Centor score and other traditional scores that require clinician-elicited signs.

RESULTS

If patients aged 15 years or older with sore throat did not visit a clinician when the new score estimated the likelihood of GAS pharyngitis to be less than 10% instead of having clinicians manage their symptoms following guidelines that use the Centor score, 230 000 visits would be avoided in the United States each year and 8500 patients with GAS pharyngitis who would have received antibiotics would not be treated with them.

LIMITATION

Real-time information about the local incidence of GAS pharyngitis, which is necessary to calculate the new score, is not currently available.

CONCLUSION

A patient-driven approach to pharyngitis diagnosis that uses this new score could save hundreds of thousands of visits annually by identifying patients at home who are unlikely to require testing or treatment.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention and the National Library of Medicine, National Institutes of Health.