Reflexive culture in adolescents and adults with group A streptococcal pharyngitis

Use of saliva-based qPCR diagnostics for the accurate, rapid, and inexpensive detection of strep throat

OBJECTIVES

Outpatient health care facilities are essential for quickly diagnosing common infectious diseases such as bacterial and viral pharyngitis. The only form of pharyngitis requiring antibiotics is strep throat (ST); however, antibiotic prescription rates are much higher than ST prevalence, suggesting antibiotics are being inappropriately prescribed. Current rapid ST diagnostics may be contributing to this problem due to the low sensitivity and variable specificity of these tests. It is best practice to verify a negative ST diagnosis with a group A Streptococcus (GAS) culture, but many clinics do not perform this test due to the additional cost and 24-72 h required to obtain results. This indicates there is great need for more accurate rapid diagnostic tools in outpatient facilities. We hypothesized that next generation qPCR technology could be adapted to detect GAS DNA from saliva samples (instead of the traditional throat swab) by creating a simple, fast, and inexpensive protocol.

METHODS

Saliva specimens collected from patients at James Madison University Health Center were used to test the effectiveness of our Chelex 100-based rapid DNA extraction method, followed by a fast protocol developed for the Open qPCR machine to accurately detect ST.

RESULTS

Our final saliva processing and qPCR protocol required no specialized training to perform and was able to detect ST with 100 % sensitivity and 100 % specificity (n=102) in 22-26 min, costing only $1.12 per sample.

CONCLUSIONS

Saliva can be rapidly analyzed via qPCR for the accurate and inexpensive detection of ST.

Evaluating the Diagnostic Paradigm for Group A and Non-Group A Streptococcal Pharyngitis in the College Student Population

Background

Acute pharyngitis is a frequent illness presenting in outpatient settings. Antibiotics are only recommended for bacterial pharyngitis caused by group A β-hemolytic streptococci (GAS); however, infections with non-group A β-hemolytic streptococci (NGAS) have similar clinical presentations and are common in young adult populations. The objective of this study was to analyze the performance of a current (expert) diagnostic algorithm for GAS pharyngitis, the Centor score, and compare it to alternative models developed to predict GAS and NGAS in a college student population.

Methods

Electronic health records were obtained for all patients who received a streptococcal rapid antigen detection test (RADT) and/or a bacterial throat culture (n = 3963) at a southeastern US university in 2014. Bivariate and multivariable regression models (least absolute shrinkage and selection operator [LASSO] and stepwise-selected) were fitted to assess and compare their diagnostic performances for GAS-positive and NGAS-positive infections.

Results

Prevalence of GAS was 18.8%. In the subset of RADT-negative patients who received bacterial throat cultures (n = 313), growth of NGAS occurred in 34.8%, with group C streptococci the most frequent isolate. Mean Centor score was higher for NGAS (3.2) vs GAS (2.9) infections (P = .0111). The area under the curve (AUC) for GAS prediction was 0.64 using the Centor score and 0.70 using the LASSO model. For NGAS, the most important features were cough, pharyngeal erythema, tonsillar exudate, and gastrointestinal symptoms (AUC = 0.63).

Conclusions

GAS and NGAS pharyngitis were indistinguishable among college students in this study utilizing a commonly applied decision score. Alternative models using additional clinical criteria may be useful for supporting diagnosis of this common illness.

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

INTRODUCTION

Streptococcal pharyngitis, which commonly occurs in children, should be treated with antibiotics. Clinical prediction rules to differentiate streptococcal pharyngitis from viral infection are not recommended in children. Rapid point-of-care (POC) antigen tests have limited sensitivity and so are not often used in Canadian paediatric emergency departments (EDs). Standard paediatric practice is to rely on laboratory-based testing, which often results in a delay before the results can be communicated to the patient; this may impede appropriate prescribing, decrease caregiver satisfaction and delay recovery. The objective of this study is to determine whether a novel rapid molecular POC assay for streptococcal pharyngitis leads to more appropriate antibiotic use in children seeking care in a paediatric ED than standard laboratory-based testing.

METHODS AND ANALYSIS

A randomised, superiority, open-label, trial with two parallel groups. Children presenting to a tertiary paediatric ED at least 3 years of age who have a throat swab ordered for diagnosis of streptococcal pharyngitis will be eligible; those who have taken antibiotics within 72 hours prior to presentation and those with additional active infections will be excluded. The primary study outcome will be appropriate antibiotic treatment at 3-5 days postenrolment. Secondary outcomes include time to symptom resolution, caregiver satisfaction, caregiver/child absenteeism, number of subsequent healthcare visits, clinician satisfaction and incremental cost-effectiveness of POC testing. A total of 352 participants will be needed.

ETHICS AND DISSEMINATION

All study documentation has been approved by the Hamilton Integrated Research Ethics board and informed consent will be obtained from all participants. Data from this trial will be presented at major conferences and published in peer-reviewed publications to facilitate collaborations with networks of clinicians experienced in the dissemination of clinical guidelines.

TRIAL REGISTRATION NUMBER

NCT04247243.

A Pragmatic Study to Evaluate the Use of a Rapid Diagnostic Test to Detect Group A Streptococcal Pharyngitis in Children With the Aim of Reducing Antibiotic Use in a UK Emergency Department

OBJECTIVE

Sore throat is a common presentation to the children's emergency department (ED), and many patients are likely prescribed antibiotics unnecessarily. We aimed to reduce antibiotic prescribing for sore throat in our UK ED through use of an established scoring system combined with a rapid diagnostic test (RDT) to detect group A streptococcal (GAS) pharyngitis.

METHODS

AB single-subject and diagnostic accuracy studies were used to measure both antibiotic prescribing rates over time and the performance of the McIsaac clinical score combined with RDT to screen for and treat GAS pharyngitis. All children between the age of 6 months and 16 years with symptoms of sore throat were eligible for inclusion. The study adhered to SQUIRE guidelines.

RESULTS

During 2014 and 2016, antibiotic prescribing rates for 210 children at baseline (median age, 3 years) and 395 children during the intervention (median age, 2 years) were assessed. The baseline prescribing rate was 79%, whereas rates after intervention were 24% and 27%, respectively. The RDT had an acceptable false-negative rate of 7.9%, poor sensitivity of 64.3%, and a negative predictive value of 92.1% when compared with conventional throat culture. A McIsaac score of 3 or more had good sensitivity (92.11%) but very low specificity (12.62%) for predicting GAS infection.

CONCLUSIONS

Despite poor RDT sensitivity and the McIsaac score's poor specificity in children, their use in combination decreased antibiotic prescribing rates in a children's ED setting.

A highly-sensitive rapid test for the diagnosis of streptococcal pharyngitis: BD veritor ™ system

INTRODUCTION

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 AND MATERIALS

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.

CONCLUSION

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.

Assessment of Pharyngitis Management at a University Student Health Services Clinic

OBJECTIVE

The objective of this study was to assess the management of students presenting with pharyngitis to a university health clinic.

METHODS

This was a retrospective cohort study. Electronic medical records of undergraduate students presenting to a university health clinic from January 1, 2012, through December 31, 2014, with complaints of sore throat and a diagnosis code for pharyngitis, tonsillitis, or sore throat were reviewed.

RESULTS

Records of 241 patients were screened and 197 patients were included. A rapid antigen detection test (RADT) was obtained in 145 (73.6%) patients. The incidence of group A streptococci (GAS) and non-GAS were 15.2% (30/197) and 10.1% (21/197), respectively. All patients with a positive RADT were prescribed antibiotics, with 13 (46.4%) receiving amoxicillin. Overall, 129 (65%) patients received an antibiotic prescription.

CONCLUSION

Management of pharyngitis at the clinic appears inconsistent with current guidelines. Approximately 2 of every 3 students were prescribed an antibiotic with no clear indication.

Comparison of 3 Nucleic Acid Amplification Tests and a Rapid Antigen Test with Culture for the Detection of Group A Streptococci from Throat Swabs

Background

Recently, the US Food and Drug Administration cleared 3 nucleic acid amplification test (NAAT) assays for detection of Streptococcus pyogenes [group A Streptococcus (GAS)] in pharyngeal specimens. However, there are limited studies evaluating the performance of these NAAT assays.

Methods

We compared the results of 3 NAATs (cobas Liat, Luminex Aries, and Cepheid Xpert Xpress) and a rapid antigen assay (Quidel QuickVue in-line strep A) with the accepted gold standard method, bacterial culture.

Results

Sixty-eight throat swab specimens collected between August and October 2017 were tested. Compared to bacterial culture, the sensitivities, specificities, positive predictive value, and negative predictive value for detecting GAS were as follows: cobas Liat: 100%, 97.4%, 96.7%, and 100%; Cepheid Xpert: 100%, 97.4%, 96.7%, and 100%; Luminex Aries: 95.2%, 100%, 100%, and 95.5%. The Quidel QuickVue in-line strep A assay showed poor sensitivity, detecting only 5.2% of culture-positive specimens.

Conclusion

The 3 NAATs have high sensitivity when compared with bacterial culture for detection of GAS. With rapid turnaround time and ease of use, these tests can be considered as reliable point-of-care tests for the diagnosis of GAS, replacing the need for back-up culture.

Prospective Postimplementation Study of Solana Group A Streptococcal Nucleic Acid Amplification Test vs Conventional Throat Culture

OBJECTIVES

We evaluated the Solana Group A Streptococcus Assay (Quidel, San Diego, CA), a nucleic acid amplification test (NAAT), as a substitute for backup culture on throat specimens with a negative rapid group A Streptococcus (GAS) antigen assay.

METHODS

During October 2016, all throat swabs from patients with a negative GAS antigen assay from local urgent care centers were processed by NAAT and conventional culture in real time.

RESULTS

The overall agreement of the 2,090 tested throat swab specimens of the NAAT with the culture was 2,050 (98%) of 2,090. Sensitivity, specificity, positive predictive value, and negative predictive value were 91.4%, 98.5%, 78.0%, and 99.5%, respectively.

CONCLUSIONS

In summary, this postimplementation study supported high sensitivity and specificity of the GAS NAAT as a backup test for negative rapid GAS antigen tests.

Evaluation of Simplexa Group A Strep Direct Kit Compared to Hologic Group A Streptococcal Direct Assay for Detection of Group A Streptococcus in Throat Swabs

Diagnosis of bacterial pharyngitis is confirmed by detection of group A Streptococcus (GAS) in patient throat samples. Testing of throat samples has historically relied on culture, but new molecular methods allow much faster test turnaround time (i.e., same day versus 48 to 72 h for culture). Our laboratory uses the Hologic GAS Direct (GASD) assay for screening more than 125,000 throat samples per year. Simplexa GAS Direct is a new real-time quantitative PCR (qPCR) assay that does not require initial DNA extraction. Performance of Simplexa qPCR was compared to GASD. A total of 289 throat swabs were collected from patients attending ambulatory clinics in Calgary, Alberta, Canada. A total of 60 (20.8%) of the samples were initially GAS positive by either method: 54 by both methods, 4 by Simplex qPCR alone, and 2 by GASD alone. An in-house PCR using a unique GAS primer set was used to resolve the 6 discrepant results. Overall, GASD compared to Simplexa qPCR had a sensitivity, specificity, positive predictive value, and negative predictive value of 93.1% versus 100%, 100% versus 100%, 100% versus 100%, and 98.31% versus 100%, respectively. Implementation of Simplexa qPCR in our laboratory setting would cost more but allow the high sample volume to be reported in half the time and save 0.62 medical laboratory technician (MLT) full-time equivalent (FTE). In comparison to culture, the implementation of Simplexa qPCR would save 2.79 medical laboratory assistant (MLA) FTE plus 0.94 MLT FTE. Simplexa qPCR has improved performance and diagnostic efficiency in a high-volume laboratory compared to GASD for GAS detection in throat swabs.

Diagnostic Accuracy of FebriDx: A Rapid Test to Detect Immune Responses to Viral and Bacterial Upper Respiratory Infections

C-reactive protein (CRP) and myxovirus resistance protein A (MxA) are associated with bacterial and viral infections, respectively. We conducted a prospective, multicenter, cross-sectional study of adults and children with febrile upper respiratory tract infections (URIs) to evaluate the diagnostic accuracy of a rapid CRP/MxA immunoassay to identify clinically significant bacterial infection with host response and acute pathogenic viral infection. The reference standard for classifying URI etiology was an algorithm that included throat bacterial culture, upper respiratory PCR for viral and atypical pathogens, procalcitonin, white blood cell count, and bandemia. The algorithm also allowed for physician override. Among 205 patients, 25 (12.2%) were classified as bacterial, 53 (25.9%) as viral, and 127 (62.0%) negative by the reference standard. For bacterial detection, agreement between FebriDx and the reference standard was 91.7%, with FebriDx having a sensitivity of 80% (95% CI: 59–93%), specificity of 93% (89–97%), positive predictive value (PPV) of 63% (45–79%), and a negative predictive value (NPV) of 97% (94–99%). For viral detection, agreement was 84%, with a sensitivity of 87% (75–95%), specificity of 83% (76–89%), PPV of 64% (63–75%), and NPV of 95% (90–98%). FebriDx may help to identify clinically significant immune responses associated with bacterial and viral URIs that are more likely to require clinical management or therapeutic intervention, and has potential to assist with antibiotic stewardship.

DNA-based culture-independent analysis detects the presence of group a streptococcus in throat samples from healthy adults in Japan

Background

Group A Streptococcus (GAS; Streptococcus pyogenes) causes a range of mild to severe infections in humans. It can also colonize healthy persons asymptomatically. Therefore, it is important to study GAS carriage in healthy populations, as carriage of it might lead to subsequent disease manifestation, clonal spread in the community, and/or diversification of the organism. Throat swab culture is the gold standard method for GAS detection. Advanced culture-independent methods provide rapid and efficient detection of microorganisms directly from clinical samples. We investigated the presence of GAS in throat swab samples from healthy adults in Japan using culture-dependent and culture-independent methods.

Results

Two throat swab samples were collected from 148 healthy volunteers. One was cultured on selective medium, while total DNA extracted from the other was polymerase chain reaction (PCR) amplified with two GAS-specific primer pairs: one was a newly designed 16S rRNA-specific primer pair, the other a previously described V-Na⁺-ATPase primer pair. Although only 5 (3.4 %) of the 148 samples were GAS-positive by the culture-dependent method, 146 (98.6 %) were positive for the presence of GAS DNA by the culture-independent method. To obtain serotype information by emm typing, we performed nested PCR using newly designed emm primers. We detected the four different emm types in 25 (16.9 %) samples, and these differed from the common emm types associated with GAS associated diseases in Japan. The different emm types detected in the healthy volunteers indicate that the presence of unique emm types might be associated with GAS carriage.

Conclusions

Our results suggest that culture-independent methods should be considered for profiling GAS in the healthy hosts, with a view to obtaining better understanding of these organisms. The GAS-specific primers (16S rRNA and V-Na⁺-ATPase) used in this study can be used to estimate the maximum potential GAS carriage in people.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-016-0858-5) contains supplementary material, which is available to authorized users.

Point-Counterpoint: A Nucleic Acid Amplification Test for Streptococcus pyogenes Should Replace Antigen Detection and Culture for Detection of Bacterial Pharyngitis

Nucleic acid amplification tests (NAATs) have frequently been the standard diagnostic approach when specific infectious agents are sought in a clinic specimen. They can be applied for specific agents such as S. pyogenes, or commercial multiplex NAATs for detection of a variety of pathogens in gastrointestinal, bloodstream, and respiratory infections may be used. NAATs are both rapid and sensitive. For many years, S. pyogenes testing algorithms used a rapid and specific group A streptococcal antigen test to screen throat specimens, followed, in some clinical settings, by a throat culture for S. pyogenes to increase the sensitivity of its detection. Now S. pyogenes NAATs are being used with increasing frequency. Given their accuracy, rapidity, and ease of use, should they replace antigen detection and culture for the detection of bacterial pharyngitis? Bobbi Pritt and Robin Patel of the Mayo Clinic, where S. pyogenes NAATs have been used for well over a decade with great success, will explain the advantages of this approach, while Richard (Tom) Thomson and Tom Kirn of the NorthShore University HealthSystem will discuss their concerns about this approach to diagnosing bacterial pharyngitis.

Rapid antigen detection test for group A streptococcus in children with pharyngitis

BACKGROUND

Group A streptococcus (GAS) accounts for 20% to 40% of cases of pharyngitis in children; the remaining cases are caused by viruses. Compared with throat culture, rapid antigen detection tests (RADTs) offer diagnosis at the point of care (within five to 10 minutes).

OBJECTIVES

To determine the diagnostic accuracy of RADTs for diagnosing GAS in children with pharyngitis. To assess the relative diagnostic accuracy of the two major types of RADTs (enzyme immunoassays (EIA) and optical immunoassays (OIA)) by indirect and direct comparison.

SEARCH METHODS

We searched CENTRAL, MEDLINE, EMBASE, Web of Science, CDSR, DARE, MEDION and TRIP (January 1980 to July 2015). We also conducted related citations tracking via PubMed, handsearched reference lists of included studies and relevant review articles, and screened all articles citing included studies via Google Scholar.

SELECTION CRITERIA

We included studies that compared RADT for GAS pharyngitis with throat culture on a blood agar plate in a microbiology laboratory in children seen in ambulatory care.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for relevance, assessed full texts for inclusion, and carried out data extraction and quality assessment using the QUADAS-2 tool. We used bivariate meta-analysis to estimate summary sensitivity and specificity, and to investigate heterogeneity across studies. We compared the accuracy of EIA and OIA tests using indirect and direct evidence.

MAIN RESULTS

We included 98 unique studies in the review (116 test evaluations; 101,121 participants). The overall methodological quality of included studies was poor, mainly because many studies were at high risk of bias regarding patient selection and the reference standard used (in 73% and 43% of test evaluations, respectively). In studies in which all participants underwent both RADT and throat culture (105 test evaluations; 58,244 participants; median prevalence of participants with GAS was 29.5%), RADT had a summary sensitivity of 85.6%; 95% confidence interval (CI) 83.3 to 87.6 and a summary specificity of 95.4%; 95% CI 94.5 to 96.2. There was substantial heterogeneity in sensitivity across studies; specificity was more stable. There was no evidence of a trade-off between sensitivity and specificity. Heterogeneity in accuracy was not explained by study-level characteristics such as whether an enrichment broth was used before plating, mean age and clinical severity of participants, and GAS prevalence. The sensitivity of EIA and OIA tests was comparable (summary sensitivity 85.4% versus 86.2%). Sensitivity analyses showed that summary estimates of sensitivity and specificity were stable in low risk of bias studies.

AUTHORS' CONCLUSIONS

In a population of 1000 children with a GAS prevalence of 30%, 43 patients with GAS will be missed. Whether or not RADT can be used as a stand-alone test to rule out GAS will depend mainly on the epidemiological context. The sensitivity of EIA and OIA tests seems comparable. RADT specificity is sufficiently high to ensure against unnecessary use of antibiotics. Based on these results, we would expect that amongst 100 children with strep throat, 86 would be correctly detected with the rapid test while 14 would be missed and not receive antibiotic treatment.

Respiratory Infections in the U.S. Military: Recent Experience and Control

This comprehensive review outlines the impact of military-relevant respiratory infections, with special attention to recruit training environments, influenza pandemics in 1918 to 1919 and 2009 to 2010, and peacetime operations and conflicts in the past 25 years. Outbreaks and epidemiologic investigations of viral and bacterial infections among high-risk groups are presented, including (i) experience by recruits at training centers, (ii) impact on advanced trainees in special settings, (iii) morbidity sustained by shipboard personnel at sea, and (iv) experience of deployed personnel. Utilizing a pathogen-by-pathogen approach, we examine (i) epidemiology, (ii) impact in terms of morbidity and operational readiness, (iii) clinical presentation and outbreak potential, (iv) diagnostic modalities, (v) treatment approaches, and (vi) vaccine and other control measures. We also outline military-specific initiatives in (i) surveillance, (ii) vaccine development and policy, (iii) novel influenza and coronavirus diagnostic test development and surveillance methods, (iv) influenza virus transmission and severity prediction modeling efforts, and (v) evaluation and implementation of nonvaccine, nonpharmacologic interventions.

[Recommendations for management of acute pharyngitis in adults]

La faringoamigdalitis aguda (FAA) en el adulto es una de las enfermedades infecciosas más comunes en la consulta del médico de familia. La etiología más frecuente es viral. Dentro de la etiología bacteriana, el principal agente responsable es Streptococcus pyogenes o estreptococo β-hemolítico del grupo A (EBHGA), causante del 5-30% de los casos. En el manejo diagnóstico, las escalas de valoración clínica para predecir la posible etiología bacteriana, son una buena ayuda para seleccionar a qué pacientes se deben practicar las técnicas de detección rápida de antígeno estreptocócico. Es conocido que, en general, sin estas técnicas se tiende al sobrediagnóstico de FAA estreptocócica, con la consiguiente prescripción innecesaria de antibióticos, muchas veces de amplio espectro. Así, con el manejo de las escalas y la técnica de diagnóstico rápido, elaboramos los algoritmos de manejo de la FAA. Los objetivos del tratamiento son acelerar la resolución de los síntomas, reducir el tiempo de contagio y prevenir las complicaciones supurativas locales y no supurativas. Los antibióticos de elección para el tratamiento de la FAA estreptocócica son penicilina y amoxicilina. La asociación de amoxicilina y clavulánico no está indicada en el tratamiento inicial en la infección aguda. Los macrólidos tampoco son un tratamiento de primera elección; su uso debe reservarse para pacientes con alergia a la penicilina. Es importante en nuestro país adecuar tanto el diagnóstico de la FAA bacteriana y la prescripción de antibióticos a la evidencia científica disponible. La implantación de protocolos de actuación en las farmacias comunitarias puede ser de utilidad para identificar y cribar los casos que no requieran tratamiento antibiótico.

[Recommendations for management of acute pharyngitis in adults]

Acute pharyngitis in adults is one of the most common infectious diseases seen in general practitioners' consultations. Viral aetiology is the most common. Among bacterial causes, the main agent is Streptococcus pyogenes or group A β-haemolytic streptococcus (GABHS), which causes 5%-30% of the episodes. In the diagnostic process, clinical assessment scales can help clinicians to better predict suspected bacterial aetiology by selecting patients who should undergo a rapid antigen detection test. If these techniques are not performed, an overdiagnosis of streptococcal pharyngitis often occurs, resulting in unnecessary prescriptions of antibiotics, most of which are broad spectrum. Consequently, management algorithms that include the use of predictive clinical rules and rapid tests have been set up. The aim of the treatment is speeding up symptom resolution, reducing the contagious time span and preventing local suppurative and non-suppurative complications. Penicillin and amoxicillin are the antibiotics of choice for the treatment of pharyngitis. The association of amoxicillin and clavulanate is not indicated as the initial treatment of acute infection. Neither are macrolides indicated as first-line therapy; they should be reserved for patients allergic to penicillin. The appropriate diagnosis of bacterial pharyngitis and proper use of antibiotics based on the scientific evidence available are crucial. Using management algorithms can be helpful in identifying and screening the cases that do not require antibiotic therapy.

[Recommendations for management of acute pharyngitis in adults]

La faringoamigdalitis aguda (FAA) en el adulto es una de las enfermedades infecciosas más comunes en la consulta del médico de familia. La etiología más frecuente es viral. Dentro de la etiología bacteriana, el principal agente responsable es Streptococcus pyogenes o estreptococo β-hemolítico del grupo A (EBHGA), causante del 5-30% de los casos. En el manejo diagnóstico, las escalas de valoración clínica para predecir la posible etiología bacteriana, son una buena ayuda para seleccionar a qué pacientes se deben practicar las técnicas de detección rápida de antígeno estreptocócico. Es conocido que, en general, sin estas técnicas se tiende al sobrediagnóstico de FAA estreptocócica, con la consiguiente prescripción innecesaria de antibióticos, muchas veces de amplio espectro. Así, con el manejo de las escalas y la técnica de diagnóstico rápido, elaboramos los algoritmos de manejo de la FAA. Los objetivos del tratamiento son acelerar la resolución de los síntomas, reducir el tiempo de contagio y prevenir las complicaciones supurativas locales y no supurativas. Los antibióticos de elección para el tratamiento de la FAA estreptocócica son penicilina y amoxicilina. La asociación de amoxicilina y clavulánico no está indicada en el tratamiento inicial en la infección aguda. Los macrólidos tampoco son un tratamiento de primera elección; su uso debe reservarse para pacientes con alergia a la penicilina. Es importante en nuestro país adecuar tanto el diagnóstico de la FAA bacteriana y la prescripción de antibióticos a la evidencia científica disponible. La implantación de protocolos de actuación en las farmacias comunitarias puede ser de utilidad para identificar y cribar los casos que no requieran tratamiento antibiótico.

Recommendations for management of acute pharyngitis in adults

Acute pharyngitis in adults is one of the most common infectious diseases seen in general practitioners' consultations. Viral aetiology is the most common. Among bacterial causes, the main agent is Streptococcus pyogenes or group A β-haemolytic streptococcus (GABHS), which causes 5%-30% of the episodes. In the diagnostic process, clinical assessment scales can help clinicians to better predict suspected bacterial aetiology by selecting patients who should undergo a rapid antigen detection test. If these techniques are not performed, an overdiagnosis of streptococcal pharyngitis often occurs, resulting in unnecessary prescriptions of antibiotics, most of which are broad spectrum. Consequently, management algorithms that include the use of predictive clinical rules and rapid tests have been set up. The aim of the treatment is speeding up symptom resolution, reducing the contagious time span and preventing local suppurative and non-suppurative complications. Penicillin and amoxicillin are the antibiotics of choice for the treatment of pharyngitis. The association of amoxicillin and clavulanate is not indicated as the initial treatment of acute infection. Neither are macrolides indicated as first-line therapy; they should be reserved for patients allergic to penicillin. The appropriate diagnosis of bacterial pharyngitis and proper use of antibiotics based on the scientific evidence available are crucial. Using management algorithms can be helpful in identifying and screening the cases that do not require antibiotic therapy.

Antimicrobial resistance: risk associated with antibiotic overuse and initiatives to reduce the problem

Antimicrobial resistance is a global public health challenge, which has accelerated by the overuse of antibiotics worldwide. Increased antimicrobial resistance is the cause of severe infections, complications, longer hospital stays and increased mortality. Overprescribing of antibiotics is associated with an increased risk of adverse effects, more frequent re-attendance and increased medicalization of self-limiting conditions. Antibiotic overprescribing is a particular problem in primary care, where viruses cause most infections. About 90% of all antibiotic prescriptions are issued by general practitioners, and respiratory tract infections are the leading reason for prescribing. Multifaceted interventions to reduce overuse of antibiotics have been found to be effective and better than single initiatives. Interventions should encompass the enforcement of the policy of prohibiting the over-the-counter sale of antibiotics, the use of antimicrobial stewardship programmes, the active participation of clinicians in audits, the utilization of valid rapid point-of-care tests, the promotion of delayed antibiotic prescribing strategies, the enhancement of communication skills with patients with the aid of information brochures and the performance of more pragmatic studies in primary care with outcomes that are of clinicians' interest, such as complications and clinical outcomes.