Are procalcitonin or other infection markers useful in the detection of group A streptococcal acute tonsillitis?

C-reactive protein point-of-care testing to guide antibiotic prescribing for respiratory tract infections

INTRODUCTION

Antimicrobial resistance is strongly correlated with the volume of antibiotics used. Most antibiotics are prescribed in primary care, mostly for respiratory tract infections (RTIs), and are often unneeded.

AREAS COVERED

The current knowledge regarding the use of C-reactive protein (CRP) rapid testing in primary care is outlined. A comprehensive literature search and narrative review of the evidence on CRP rapid testing for patients presenting with symptoms of RTIs was conducted to develop a holistic perspective on the subject. Relevant studies were identified through a PubMed search up to April 2025.

EXPERT OPINION

CRP testing is an effective, cost-efficient tool to reduce unnecessary antibiotic use for lower RTIs in primary care. This test should be included in guidelines and implemented when a clinician is uncertain about the prognosis of an infection. It should complement history taking and clinical examination before deciding to prescribe antibiotics, primarily to rule out serious infections, but should never be used as a standalone test. To tackle antimicrobial resistance, the reduction of unnecessary antibiotic use in acute RTIs is optimized with clear guidance, advanced communication training for clinicians, and delayed antibiotic prescribing strategies when applicable.

[Clinical diagnosis of group A streptococcal pharyngitis and progress in the application of scoring systems]

Pharyngitis can be caused by various pathogens, including viruses and bacteria. Group A streptococcus (GAS) is the most common bacterial cause of pharyngitis. However, distinguishing GAS pharyngitis from other types of upper respiratory tract infections is challenging in clinical settings. This often leads to empirical treatments and, consequently, the overuse of antimicrobial drugs. With the advancement of antimicrobial drug management and healthcare payment reform initiatives in China, reducing unnecessary testing and prescriptions of antimicrobial drugs is imperative. To promote standardized diagnosis and treatment of GAS pharyngitis, this article reviews various international guidelines on the clinical diagnosis and differential diagnosis of GAS pharyngitis, particularly focusing on clinical scoring systems guiding laboratory testing and antimicrobial treatment decisions for GAS pharyngitis and their application recommendations, providing a reference for domestic researchers and clinical practitioners.

The use and usefulness of point-of-care tests in patients with pharyngotonsillitis - an observational study in primary health care

BACKGROUND

Rapid antigen detection tests (RADT) for Group A streptococci (GAS) and point-of-care tests for C-reactive protein (CRP) are commonly used in patients with pharyngotonsillitis in Sweden and Denmark although CRP testing is not supported by guidelines. We aimed to describe (1) the proportion of patients tested with RADT and/or CRP, (2) the relation between test results and antibiotic prescribing, and (3) the association between CRP level and microbial aetiology.

METHODS

We used a post-hoc-analysis of data collected in primary health care in a prospective aetiological study of 220 patients 15-45 years old diagnosed with pharyngotonsillitis. The outcomes of RADTs and CRP tests were related to antibiotic prescribing and microbial aetiology.

RESULTS

A RADT was used in 94% of the patients. A CRP test was used in 50% of the patients but more commonly in those with a negative RADT (59%) than in those with a positive RADT (38%) (p = 0.005). Most (74%) CRP tests were used in patients with a negative RADT. Antibiotic prescribing differed greatly between patients with a positive RADT (96%) and patients with a negative RADT (17%) (p < 0.001). In patients with a negative RADT, there was a positive association between CRP value and antibiotic prescribing (OR 1.05; 95% CI 1.02-1.07; p < 0.001). Patients with CRP values ≤ 30 mg/l were seldomly prescribed antibiotics. Patients with GAS in culture had the highest median CRP (46 mg/l), which was higher than in patients without GAS (8 mg/l; p < 0.001). However, the positive predictive value for GAS never exceeded 0.60 (95% CI 0.31-0.83) at the investigated CRP levels.

CONCLUSIONS

The widespread use of tests is a major deviation from national guidelines. Most CRP tests were used in patients with a negative RADT, suggesting a belief in the added value of a CRP test, and the CRP result seemed to influence antibiotic prescribing. However, as an aetiological test, CRP is not useful for predicting GAS.

Group A β-hemolytic Streptococcal Pharyngitis: An Updated Review

BACKGROUND

Group A ß-hemolytic Streptococcus (GABHS) is the leading bacterial cause of acute pharyngitis in children and adolescents worldwide.

OBJECTIVE

This article aims to familiarize clinicians with the clinical manifestations, evaluation, diagnosis, and management of GABHS pharyngitis.

METHODS

A search was conducted in December 2022 in PubMed Clinical Queries using the key term "group A β-hemolytic streptococcal pharyngitis". This review covers mainly literature published in the previous ten years.

RESULTS

Children with GABHS pharyngitis typically present with an abrupt onset of fever, intense pain in the throat, pain on swallowing, an inflamed pharynx, enlarged and erythematous tonsils, a red and swollen uvula, enlarged tender anterior cervical lymph nodes. As clinical manifestations may not be specific, even experienced clinicians may have difficulties diagnosing GABHS pharyngitis solely based on epidemiologic or clinical grounds alone. Patients suspected of having GABHS pharyngitis should be confirmed by microbiologic testing (e.g., culture, rapid antigen detection test, molecular point-of-care test) of a throat swab specimen prior to the initiation of antimicrobial therapy. Microbiologic testing is generally unnecessary in patients with pharyngitis whose clinical and epidemiologic findings do not suggest GABHS. Clinical score systems such as the Centor score and McIssac score have been developed to help clinicians decide which patients should undergo diagnostic testing and reduce the unnecessary use of antimicrobials. Antimicrobial therapy should be initiated without delay once the diagnosis is confirmed. Oral penicillin V and amoxicillin remain the drugs of choice. For patients who have a non-anaphylactic allergy to penicillin, oral cephalosporin is an acceptable alternative. For patients with a history of immediate, anaphylactic-type hypersensitivity to penicillin, oral clindamycin, clarithromycin, and azithromycin are acceptable alternatives.

CONCLUSION

Early diagnosis and antimicrobial treatment are recommended to prevent suppurative complications (e.g., cervical lymphadenitis, peritonsillar abscess) and non-suppurative complications (particularly rheumatic fever) as well as to reduce the severity of symptoms, to shorten the duration of the illness and to reduce disease transmission.

Use of Host Response to Refine the Diagnosis of Group A Streptococcal Pharyngitis

BACKGROUND

Current diagnostic tests for pharyngitis do not distinguish between symptomatic group A Streptococcus (GAS) infection and asymptomatic colonization, resulting in over-diagnosis and unnecessary use of antibiotics. We assessed whether measures of host response could make this distinction.

METHODS

We enrolled 18 children with pharyngitis having Centor scores of 4 or 5 and 21 controls without pharyngitis or other acute infections. Both groups had throat cultures, molecular tests for GAS and respiratory viruses and IgM serology for Epstein-Barr virus. Host response was evaluated with white blood cell count (WBC), C-reactive protein (CRP), procalcitonin (PCT), and sequencing of RNA from peripheral blood leukocytes.

RESULTS

Of 18 cases, 11 had GAS pharyngitis, 3 had adenovirus pharyngitis and 4 had other pharyngitis. Among asymptomatic controls, 5 were positive for GAS. WBC, CRP, and PCT were higher in subjects with pharyngitis compared to asymptomatic controls including those with GAS. Transcriptional profiles from children with symptomatic GAS were clearly distinct from those of children in all other groups. The levels of two genes, CD177 and TLR5 each individually accurately distinguished between symptomatic and asymptomatic GAS. Optimal diagnostic sensitivity and specificity were achieved by the combination of CRP and PCT, and by each of the two gene markers.

CONCLUSION

In this exploratory study, we showed that traditional measures of inflammation and markers of host gene expression distinguish between symptomatic and asymptomatic GAS. These results point to future rapid molecular approaches for improving the diagnosis of GAS pharyngitis, that may help reduce unnecessary antibiotic use.

Clinical Utility of Procalcitonin on Antibiotic Stewardship: A Narrative Review

Procalcitonin (PCT) was discovered as a useful marker for bacterial infection. Following its discovery, there have been a substantial number of clinical studies conducted to evaluate the presence of bacterial infections, and to guide antibiotic treatment by the stratified levels of PCT. Clinical evidence suggests that antibiotic treatment by PCT-guided antibiotic stewardship has been associated with a reduction in antibiotic usage without an increase in adverse outcomes. The use of PCT was approved by the Food and Drug Administration in the United States of America in 2017 to guide antibiotic treatment in sepsis and lower respiratory tract infections (LRTIs). In Korea, the use of PCT for sepsis and for pneumonia was approved in 2015 and 2022, respectively. This review will discuss the clinical utility of PCT on antibiotic stewardship in the management of sepsis and LRTIs including pneumonia.

Guidelines for the Use of Procalcitonin for Rational Use of Antibiotics

How to cite this article: Khilnani GC, Tiwari P, Zirpe KG, Chaudhary D, Govil D, Dixit S, et al. Guidelines for the Use of Procalcitonin for Rational Use of Antibiotics. Indian J Crit Care Med 2022;26(S2):S77-S94.

Echocardiographic Parameters, Clinical Profile and Presence of Streptococcus pyogenes Virulent Genes in Pharyngitis and Rheumatic Fever

Streptococcus pyogenes is a gram positive pathogen causing pharyngitis, mild infections to chronic complications (Rheumatic Heart Disease, RHD). In this study, echocardiographic and clinical profile in pharyngitis, rheumatic fever patients were compared with virulent genes emm, spe A, spe B and sof. Nearly 107 subjects were classified into Group I – Pharyngitis (n=30), Group II – Rheumatic Fever (n=30) and Group III – healthy controls (n=47). The isolated S.pyogenes from Group I and Group II patient’s throat swab were subjected to 16S rRNA gene sequence. Multiplex PCR was done for identification of virulent genes. Electrocardiogram and Echocardiography was done for all the groups. For statistical analysis ANOVA and t-test were used. Comparison between groups were done by Tukey’s Multiple Comparison test. Among 107 isolates, 16.7% emm gene were detected in Group I and 23.3% in Group II, 56.67 % of spe B in Group I and 73.33 % in Group II, 36.67% of sof gene in Group I and 40% in Group II. Mitral Regurgitation was most commonly encountered in rheumatic fever. Hemoglobin (<0.001) and RDW (<0.001) was significantly lower in Rheumatic Fever whereas Platelet count (<0.001) and Neutrophil (<0.001) was significantly higher when compared with control subjects by Tukey’s Multiple Comparison test. When we compared the genetic relationship with the Echocardiographic findings, presence of one, two or three genes showed moderate to severe regurgitation in Rheumatic Fever subjects.

A controlled human infection model of Streptococcus pyogenes pharyngitis (CHIVAS-M75): an observational, dose-finding study

BACKGROUND

Streptococcus pyogenes is a leading cause of infection-related morbidity and mortality. A reinvigorated vaccine development effort calls for new clinically relevant human S pyogenes experimental infection models to support proof of concept evaluation of candidate vaccines. We describe the initial Controlled Human Infection for Vaccination Against S pyogenes (CHIVAS-M75) study, in which we aimed to identify a dose of emm75 S pyogenes that causes acute pharyngitis in at least 60% of volunteers when applied to the pharynx by swab.

METHODS

This observational, dose-finding study was done in a clinical trials facility in Melbourne (VIC, Australia). Groups of healthy volunteers aged 18-40 years, at low risk of complicated S pyogenes disease, and without high type-specific anti-emm75 IgG antibodies against the challenge strain were challenged and closely monitored as inpatients for up to 6 days, and then as outpatients for 6 months. Antibiotics were started upon diagnosis (clinical signs and symptoms of pharyngitis and a positive rapid molecular test) or after 5 days in those without pharyngitis. Rapid test results were confirmed by standard bacterial culture. After a sentinel participant, cohorts of five and then ten participants were challenged, with protocol-directed dose-escalation or de-escalation for subsequent cohorts. The primary outcome was the proportion of participants at each dose level with pharyngitis by day 5 after challenge. The study is registered with ClinicalTrials.gov, NCT03361163.

FINDINGS

Between July 10, 2018, and Sept 23, 2019, 25 healthy adults were challenged with emm75 S pyogenes and included in analyses. Pharyngitis was diagnosed in 17 (85%; 95% CI 62-97) of 20 participants at the starting dose level (1-3 × 10⁵ colony-forming units [CFU]/mL). This high proportion prompted dose de-escalation. At the lower dose level (1-3 × 10⁴ CFU/mL), pharyngitis was diagnosed in one of five participants. Immunological, biochemical, and microbiological results supported the clinical picture, with acute symptomatic pharyngitis characterised by pharyngeal colonisation by S pyogenes accompanied by significantly elevated C-reactive protein and inflammatory cytokines (eg, interferon-γ and interleukin-6), and modest serological responses to streptolysin O and deoxyribonuclease B. There were no severe (grade 3) or serious adverse events related to challenge.

INTERPRETATION

We have established a reliable pharyngitis human infection model with reassuring early safety findings to accelerate development of vaccines and other interventions to control disease due to S pyogenes.

FUNDING

Australian National Health and Medical Research Council.

Microbiology of parapharyngeal abscesses in adults: in search of the significant pathogens

We aimed to describe the microbiology of parapharyngeal abscess (PPA) and point out the likely pathogens using the following principles to suggest pathogenic significance: (1) frequent recovery, (2) abundant growth, (3) growth in relative abundance to other microorganisms, (4) percentage of the isolates recovered in both absolute and relative abundance, (5) more frequent recovery in PPA pus compared with tonsillar surface and tissue. Comprehensive bacterial cultures were performed on specimens obtained from adult patients (n = 60) with surgically verified PPA, who were prospectively enrolled at five Danish ear-nose-throat departments. The prevalent isolates (in PPA pus) were unspecified anaerobes (73%), non-hemolytic streptococci (67%), Streptococcus anginosus group (SAG) (40%), Corynebacterium spp. (25%), Neisseria spp. (23%), Fusobacterium spp. (22%), Fusobacterium necrophorum (17%), Prevotella spp. (12%), and Streptococcus pyogenes (10%). The bacteria most frequently isolated in heavy (maximum) growth were unspecified anaerobes (60%), SAG (40%), F. necrophorum (23%), and Prevotella spp. (17%). The predominant microorganisms (those found in highest relative abundance) were unspecified anaerobes (53%), SAG (28%), non-hemolytic streptococci (25%), F. necrophorum (15%), S. pyogenes (10%), and Prevotella spp. (10%). Four potential pathogens were found in both heavy growth and highest relative abundance in at least 50% of cases: F. necrophorum, Prevotella spp., SAG, and S. pyogenes. SAG, Prevotella spp., F. necrophorum, S. pyogenes, and Bacteroides spp. were recovered with the same or higher frequency from PPA pus compared with tonsillar tissue and surface. Our findings suggest that SAG, F. necrophorum, Prevotella, and S. pyogenes are significant pathogens in PPA development.

The value of transcutaneous ultrasound in the diagnosis of tonsillar abscess: A retrospective analysis

OBJECTIVE

To identify the appropriate treatment in the tonsillar region's infections, a distinction between tonsillitis with or without abscess formation is essential. Ultrasound proved to be a valuable method in identifying abscess formation in the head and neck region. However, no report described the assessment of the tonsil region. This study aims to determine the feasibility of transcervical ultrasound for abscess visualization in the palatal tonsillar region.

METHODS

Retrospective analysis of 354 patients presenting with clinical suspicion of tonsillar abscess to a tertiary referral center and university hospital. All patients received a transcervical ultrasound to establish a primary diagnosis. The existence of an abscess was confirmed by puncture and incision, or final tonsillectomy. If no abscess could be delineated, non-abscessing tonsillitis was supposed, and conservative primary therapy and closed follow-up examinations were performed.

RESULTS

After the first diagnostic ultrasound examination, in 257 cases (72.59%), the diagnosis of an abscess could be established, but in 97 cases (27.40%), due to missing abscess formation criteria, non-abscessing tonsillitis was documented. Overall, ultrasonography demonstrated an overall accuracy of 78.8% in this selected cohort. The sensitivity, specificity, PPV, and NPV after the first ultrasound examination were calculated with 75.1%, 88.6%, 94.6%, and 57.3%, respectively.

CONCLUSION

The presented data confirm that an abscess formation due to tonsillitis can be detected by transcervical ultrasound, enabling prompt, adequate management. As transcervical ultrasound can be conducted fast and is not associated with radiation, it can be regarded as a first-line diagnostic tool in this condition.

Clinical Usefulness of Acute-Phase Markers in Distinguishing between PFAPA and Other Exudative Tonsillitis Causes: A Methodological Study

BACKGROUND

We investigated the practical use of procalcitonin (PCT), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and complete blood count (CBC) parameters in distinguishing periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis syndrome (PFAPA) attacks from exudative tonsillitis associated with group A streptococcus (GAS) and Epstein-Barre virus (EBV).

METHODS

The study population consisted of cases with exudative tonsillitis who had been subsequently diagnosed as PFAPA, EBV, and GAS tonsillitis through a period of 6 years. We retrieved the CBC, ESR, CRP and PCT data from patients' medical records.

RESULTS

Of the patients, 47 (35.6%) had PFAPA, 36 (27.3%) had GAS and 49 (37.1%) had EBV tonsillitis. Median CRP, ESR and PCT values of patients with PFAPA were 78 (17-92) mg/dl, 44 (11-83) mm/h, 0.16 (0.01-1.45) ng/ml, respectively. The CRP and ESR levels were significantly higher in PFAPA and GAS groups compared with the EBV group (p = 0.001). There was no significant difference between the groups regarding the PCT levels.

CONCLUSION

The study indicated no benefit of PCT in distinguishing PFAPA from the others. However, we found that CRP, ESR, and CBC parameters could be useful in identifying PFAPA and GAS than EBV tonsillitis.

[How to reduce the antibacterial load in the treatment of acute tonsillitis and pharyngitis? Possible tactics and practical approaches]

Acute tonsillopharyngitis is one of the most frequent reasons for visiting a doctor and prescribing inappropriate antibiotic therapy (ABT). There are several reasons for this - from the difficulties of etiological diagnosis and the development of relapses and possible severe complications to the personal attitude of doctors and patients to the choice of treatment. At the same time, the issue of antibiotic resistance and other aspects associated with the prescription of ABT is one of the most important problems of modern healthcare worldwide. The purpose of this review is to demonstrate the best practical approaches to the choice of treatment tactics for acute tonsillitis (AT) in the treatment of children and adults, with an emphasis on reducing the load of ABT. The review examines the indications and disadvantages of clinical and laboratory diagnosis of AT. There are no highly sensitive clinical and laboratory instruments that differentiate viral and bacterial AT. Exudativeis AT in children is not an underlying symptom of streptococcal etiology. Despite the limitations, the modified Centor/McIsaac score ≥3 (taking into account age and the presence of respiratory symptoms) should be used as an indication for ABT in conjunction with a rapid streptotest and subsequent bacteriological culture for S. pyogenes if the screening test is negative. Additional examinations (determination of leukocytosis, CRP and procalcitonin test) are not required for most patients. ABT should not be given to low-risk patients for the treatment and prevention of rheumatic fever and acute glomerulonephritis. Prevention of purulent complications (paratonsillitis and retropharyngeal abscess, acute otitis media, cervical lymphadenitis, mastoiditis, or acute sinusitis) is not a specific indication for ABT in AT and is not required in most patients. The strategy of «delayed antibiotic prescriptions» with monitoring the patient's condition for 2-3 days is appropriate and highly effective in doubtful cases. The drugs of choice for treatment of AT are amoxicillin and oral forms of I and II generation cephalosporins. Macrolides are not indicated as first-line treatment for AT. The course of ABT for streptococcal AT is 10 days, which reduces the risk of recurrent episode. Topical drugs can be the only means of etiopathogenetic treatment with viral AT, or additional for bacterial AT. Their use not only relieves sore throat, but also shortens the duration of the disease, and also improves the patients prognosis. Benzalkonium chloride + tyrothricin + benzocaine (Dorithyrcin) may be a rational drug of choice for topical therapy due to the available clinical evidence. There is a significant reserve for reducing the load of ABT during AT. Further clinical trials are needed to assess the efficacy of short courses of ABT in the treatment of AT in high-income countries and provide a basis for strong recommendations for topical drug use. This can reduce the frequency of ABT prescribing and increase the level of interaction between specialists and patients.

Danish GPs' and practice nurses' management of acute sore throat and adherence to guidelines

BACKGROUND

Sore throat is a frequent presentation of acute respiratory tract infections in general practice. Though these infections are often harmless and self-limiting, antibiotics are frequently prescribed. In Denmark, practice nurses manage an increasing part of patients with acute minor illnesses.

OBJECTIVES

We aimed (i) to investigate Danish practice nurses' and GPs' management of patients presenting with a sore throat and (ii) to explore to what extent management is according to current Danish guidelines.

METHODS

A cross-sectional study was conducted during winter 2017, involving GPs and practice nurses in Danish general practices. Patients with a sore throat were registered according to the Audit Project Odense method.

RESULTS

A total of 44 practices participated with the registration of 1503 patients presenting with a sore throat. Most patients had a strep A test performed, especially when managed by a practice nurse (84.6% versus 61.8%, χ2 = 90.1, P < 0.05). In total, 40.6% of performed strep A tests were not according to guideline recommendations. Antibiotics were prescribed for about one-third of patients, regardless whether managed by a practice nurse or a GP (χ2 = 0.33, P = 0.57). However, 32.4% of these prescriptions were not in line with Danish guidelines.

CONCLUSION

Patients with acute sore throat were managed similarly by GPs and practice nurses, apart from a higher use of strep A tests in patients seen by practice nurses. Importantly, this study demonstrated that there is still room for improvement of the management of these patients in Danish general practice.

Association Between Rapid Antigen Testing and Antibiotic Use and Accuracy of Peripheral Blood Parameters in Detecting Group A Streptococcus in Children With Tonsillopharyngitis

Objectives: To investigate the effect of rapid antigen testing (RAT) on the practice of antibiotic prescription as well as the accuracy of peripheral blood neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP) values in detecting group A beta-hemolytic Streptococcus (GABHS) in children with tonsillopharyngitis. Methods: In a multicenter study performed in Turkey, we retrospectively analyzed data from 668 consecutive pediatric patients under 17 years of age, who presented with signs and symptoms of tonsillopharyngitis and underwent RAT. The rates of positive and negative RAT results were determined and patients' antibiotic prescriptions were examined in relation to RAT results. In addition, the accuracy of peripheral blood NLR and CRP values was examined for 212 patients whose laboratory data were available, with RAT as the reference standard. Results: Positive RAT results were observed in 190 of 668 (28.4%) patients. Antibiotics were prescribed to all 190 patients with positive RAT results and to 8 of 478 patients with negative RAT results. Overall, the rate of antibiotic prescription was 29.6%. Patients with positive and negative RAT results did not differ significantly with regard to NLR and CRP values. In ROC analysis, the area under the ROC curve (AUC) of NLR and CRP were 0.54 (95% confidence interval [CI] 0.45-0.64), and 0.55 (95% CI 0.45-0.65), respectively. Conclusion: RAT results proved highly associated with antibiotic prescribing, suggesting that RATs could be of great value in preventing unnecessary antibiotic use. Our findings also suggest that NLR and CRP are poorly accurate to identify GABHS in children with tonsillopharyngitis.

A prospective, multi-centre US clinical trial to determine accuracy of FebriDx point-of-care testing for acute upper respiratory infections with and without a confirmed fever

BACKGROUND

FebriDx is a 10-minute disposable point-of-care test designed to identify clinically significant systemic host immune responses and aid in the differentiation of bacterial and viral respiratory infection by simultaneously detecting C-reactive protein (CRP) and myxovirus resistance protein A (MxA) from a fingerstick blood sample. FebriDx diagnostic accuracy was evaluated in the emergency room and urgent care setting.

METHODS

A prospective, multicentre, observational cohort study of acute upper respiratory tract infections (URIs), with and without a confirmed fever at the time of enrolment, was performed to evaluate the diagnostic accuracy of FebriDx to identify clinically significant bacterial infection with host response and acute pathogenic viral infection. The reference method consisted of an algorithm with physician override that included bacterial cell culture, respiratory PCR panels for viral and atypical pathogens, procalcitonin, and white blood cell count.

RESULTS

Among 220 patients enrolled, 100% reported fever 100.5°F within the last 72 hours while 55% had a measured hyperthermia (T > 100.4) at the time of enrolment. FebriDx demonstrated a sensitivity of 95% (95% CI: 77-100%), specificity of 94% (88-98%), PPV of 76% (59-87%), and a NPV of 99% (93-100%).

CONCLUSION

FebriDx may identify clinically significant bacterial URI's and supports outpatient antibiotic decisions. Key messages FebriDx is an outpatient POC test designed to identify a clinically significant systemic host immune response and aid in the differentiation of viral and bacterial infection through rapid measurement of MxA and CRP from a fingerstick blood sample. FebriDx test was determined to be an accurate test, with a 85% sensitivity, 93% specificity and 97% NPV to rule out bacterial infection for any patient presenting with symptoms and reported fever within the prior 3 days, and when confirming fever (hyperthermia) at the time of testing, the test was even more sensitive (95%) and specific (94%) with a 99% NPV. FebriDx may support antibiotic stewardship by rapidly identifying clinically significant bacterial URIs.

Outpatient Antibiotic Stewardship: A Growing Frontier-Combining Myxovirus Resistance Protein A With Other Biomarkers to Improve Antibiotic Use

Background

The majority of oral antibiotics are prescribed in outpatient primary and urgent care clinics for acute respiratory infections. Effective antibiotic stewardship must include proper prescribing for outpatients as well as for those in a hospital or long-term care facility.

Methods

Major databases, including MEDLINE and the Cochrane Library, were searched for prospective human clinical studies, including children and/or adults published between January 1966 and November 2017 that evaluated Myxovirus resistance protein A (MxA) as a biomarker for diagnosing viral infections as well as both C-reactive protein (CRP) and procalcitonin (PCT) as potential biomarkers for identifying and differentiating true bacterial upper respiratory infection (URI) from colonization.

Results

Ten prospective human studies, totaling 1683 patients, were identified that evaluated MxA as a viral biomarker in children and/or adults. Both systematic review articles, meta-analyses, and randomized controlled clinical trials that examined CRP and/or PCT as a biomarker for identifying clinically significant bacterial infections and supporting antibiotic stewardship were identified.

Conclusions

Quick and accurate differentiation between a viral and bacterial respiratory infection is critical to effectively combat antibiotic misuse. MxA expression in peripheral blood is a highly specific marker for viral infection. Combining MxA with other inflammatory biomarkers to test for respiratory infections offers enhanced sensitivity and specificity, forming an excellent tool for antibiotic stewardship in the outpatient setting.

Effects of procalcitonin testing on antibiotic use and clinical outcomes in patients with upper respiratory tract infections. An individual patient data meta-analysis

BACKGROUND

Several trials found procalcitonin (PCT) helpful for guiding antibiotic treatment in patients with lower respiratory tract infections and sepsis. We aimed to perform an individual patient data meta-analysis on the effects of PCT guided antibiotic therapy in upper respiratory tract infections (URTI).

METHODS

A comprehensive search of the literature was conducted using PubMed (MEDLINE) and Cochrane Library to identify relevant studies published until September 2016. We reanalysed individual data of adult URTI patients with a clinical diagnosis of URTI. Data of two trials were used based on PRISMA-IPD guidelines. Safety outcomes were (1) treatment failure defined as death, hospitalization, ARI-specific complications, recurrent or worsening infection at 28 days follow-up; and (2) restricted activity within a 14-day follow-up. Secondary endpoints were initiation of antibiotic therapy, and total days of antibiotic exposure.

RESULTS

In total, 644 patients with a follow up of 28 days had a final diagnosis of URTI and were thus included in this analysis. There was no difference in treatment failure (33.1% vs. 34.0%, OR 1.0, 95% CI 0.7-1.4; p=0.896) and days with restricted activity between groups (8.0 vs. 8.0 days, regression coefficient 0.2 (95% CI -0.4 to 0.9), p=0.465). However, PCT guided antibiotic therapy resulted in lower antibiotic prescription (17.8% vs. 51.0%, OR 0.2, 95% CI 0.1-0.3; p<0.001) and in a 2.4 day (95% CI -2.9 to -1.9; p<0.001) shorter antibiotic exposure compared to control patients.

CONCLUSIONS

PCT guided antibiotic therapy in the primary care setting was associated with reduced antibiotic exposure in URTI patients without compromising outcomes.

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.

Aetiology of febrile pharyngitis in children: Potential of myxovirus resistance protein A (MxA) as a biomarker of viral infection

Objectives

Besides group A streptococcus (GAS), microbial causes of pharyngitis in children are not well known. We aimed to document the viral and bacterial aetiology of pharyngitis and to assess the pathogenic role of viruses by determining the myxovirus resistance protein A (MxA) in the blood as a marker of interferon response.

Methods

In this prospective observational study, throat swabs and blood samples were collected from children (age 1–16 years) presenting to the emergency department with febrile pharyngitis. Microbial cause was sought by bacterial culture, polymerase chain reaction, and serology. Blood MxA level was determined.

Results

A potential pathogen was detected in 88% of 83 patients: GAS alone in 10%, GAS and viruses in 13%, group C or G streptococci alone in 2% and together with viruses in 3%, and viruses alone in 59% of cases. Enteroviruses, rhinoviruses, and adenoviruses were the most frequently detected viruses. Blood MxA levels were higher in children with viral (880 [245–1250] μg/L; median [IQR]) or concomitant GAS-viral (340 [150–710] μg/L) than in those with sole GAS (105 [80–160] μg/L) infections.

Conclusions

Detection of respiratory viruses simultaneously with elevated blood MxA levels supports the causative role of viruses in the majority of children with pharyngitis.

•

We evaluated the microbiological aetiology of febrile pharyngitis in 83 children.

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A potential pathogen could be detected in 88% and virus in 76% of patients.

•

Blood myxovirus resistance protein A (MxA) levels were elevated in most of the patients with virus finding.

•

MxA is a promising biomarker of virus infection.

Guidelines for the Antibiotic Use in Adults with Acute Upper Respiratory Tract Infections

These guidelines were developed as part of the 2016 Policy Research Servicing Project by the Korea Centers for Disease Control and Prevention. A multidisciplinary approach was taken to formulate this guideline to provide practical information about the diagnosis and treatment of adults with acute upper respiratory tract infection, with the ultimate aim to promote the appropriate use of antibiotics. The formulation of this guideline was based on a systematic literature review and analysis of the latest research findings to facilitate evidence-based practice, and focused on key questions to help clinicians obtain solutions to clinical questions that may arise during the care of a patient. These guidelines mainly cover the subjects on the assessment of antibiotic indications and appropriate selection of antibiotics for adult patients with acute pharyngotonsillitis or acute sinusitis.

Alteration of thiol-disulphide homeostasis in acute tonsillopharyngitis

OBJECTIVE

Thiol-disulphide homeostasis (TDH) has a critical role in various clinical disorders. We aimed to assess the association of TDH with acute tonsillopharyngitis (AT) in children.

METHODS

This study included 94 (73 viral and 21 bacterial) tonsillopharyngitis patients and 88 control children. Their native thiol, total thiol, and disulphide levels were measured.

RESULTS

Viral and bacterial tonsillopharyngitis patients had lower native thiol levels compared with healthy children (P < 0.001 and P = 0.008, respectively). Both groups had lower total thiol levels compared with control children (P = 0.002 for viral, P = 0.011 for bacterial). The disulphide levels were lower in bacterial than in viral tonsillopharyngitis patients (P = 0.04), and there was a significant difference between viral tonsillopharyngitis patients and the control group (P < 0.001). The native/total thiol ratio in each patient group was lower than in the control group (P < 0.001 for viral, P = 0.017 for bacterial). The disulphide/native thiol and disulphide/total thiol ratios were significantly higher in viral (P < 0.001 for both) and bacterial tonsillopharyngitis patients (P = 0.017 for both) than in healthy children. In all patients, a correlation was found between the levels of C-reactive protein (CRP) and native thiol (r = -0.211, P = 0.04), CRP and total thiol (r = -0.217, P = 0.036), white blood cell (WBC) and native thiol (r = -0.228, P = 0.002), WBC and total thiol (r = -0.191, P = 0.01), and WBC and disulphide (r = 0.160, P = 0.03).

DISCUSSION

TDH is altered in AT in children. The alteration is more prominent in viral than in bacterial tonsillopharyngitis.

The role of the mean platelet volume and neutrophil-to-lymphocyte ratio in peritonsillar abscesses

Introduction

Peritonsillar abscess is a serious infectious disease of the tonsillar tissue. Treatment generally requires both medical and surgical approaches to relieve the symptoms. Recently, in addition to clinical follow-up, some inflammatory markers, such as the mean platelet volume and neutrophil-to-lymphocyte ratio, have been considered to be additional inflammatory monitoring markers in inflammatory diseases.

Objective

The aim of this study was to describe the role of mean platelet volume and neutrophil-to-lymphocyte ratio in patients with peritonsillar abscess.

Methods

A retrospective study was conducted in 88 patients with peritonsillar abscess and 88 healthy individuals. We analyzed the white blood cell count, neutrophil count, lymphocyte count, platelet count, C-reactive protein, mean platelet volume and neutrophil-to-lymphocyte ratio values and compared them among the patient and control groups.

Results

The mean platelet volume levels were significantly higher in the peritonsillar abscess pretreatment group than in the peritonsillar abscess posttreatment group and the control group. A mean platelet volume value of 8.7 was the optimal cut-off value for evaluating the sensitivity, specificity, positive predictive value and negative predictive value of 75%, 65.9%, 68% and 72%, respectively. The neutrophil-to-lymphocyte ratio levels were significantly higher in the peritonsillar abscess pretreatment group than in the peritonsillar abscess post-treatment group and the control group. A neutrophil-to-lymphocyte ratio value of 3.08 was the optimal cut-off value for evaluating the sensitivity, specificity, positive predictive value and negative predictive value of 90.9%, 90.9%, 90.9% and 90.9%, respectively. While the white blood cell count, neutrophil count, lymphocyte count and C-reactive protein values were significantly different among the patient and control groups (p < 0.05), the platelet count was not significantly different among the patient and control groups (p > 0.05).

Conclusion

The mean platelet volume and neutrophil-to-lymphocyte ratio values made us think that these parameters were quick, inexpensive and reliable inflammatory follow-up parameters and could be easily integrated into daily practice for peritonsillar abscess treatment except platelet count.

Clinical practice guideline: tonsillitis I. Diagnostics and nonsurgical management

More than 120,000 patients are treated annually in Germany to resolve repeated episodes of acute tonsillitis. Therapy is aiming at symptom regression, avoidance of complications, reduction in the number of disease-related absences in school or at work, increased cost-effectiveness and improved quality of life. The purpose of this part of the guideline is to provide clinicians in any setting with a clinically focused multi-disciplinary guidance through different conservative treatment options in order to reduce inappropriate variation in clinical care, improve clinical outcome and reduce harm. Surgical management in terms of intracapsular as well as extracapsular tonsillectomy (i.e. tonsillotomy) is the subject of part II of this guideline. To estimate the probability of tonsillitis caused by β-hemolytic streptococci, a diagnostic scoring system according to Centor or McIsaac is suggested. If therapy is considered, a positive score of ≥3 should lead to pharyngeal swab or rapid test or culture in order to identify β-hemolytic streptococci. Routinely performed blood tests for acute tonsillitis are not indicated. After acute streptococcal tonsillitis, there is no need to repeat a pharyngeal swab or any other routine blood tests, urine examinations or cardiological diagnostics such as ECG. The determination of the antistreptolysin O-titer (ASLO titer) and other antistreptococcal antibody titers do not have any value in relation to acute tonsillitis with or without pharyngitis and should not be performed. First-line therapy of β-hemolytic streptococci consists of oral penicillin. Instead of phenoxymethylpenicillin–potassium (penicillin V potassium), also phenoxymethlpenicillin–benzathine with a clearly longer half-life can be used. Oral intake for 7 days of one of both the drugs is recommended. Alternative treatment with oral cephalosporins (e.g. cefadroxil, cefalexin) is indicated only in cases of penicillin failure, frequent recurrences, and whenever a more reliable eradication of β-hemolytic streptococci is desirable. In cases of allergy or incompatibility of penicillin, cephalosporins or macrolides (e.g. Erythromycin-estolate) are valuable alternatives.

Management of patients with respiratory infections in primary care: procalcitonin, C-reactive protein or both?

Use of inflammatory biomarkers to guide antibiotic decisions has shown promising results in the risk-adapted management of respiratory tract infections, mainly in the inpatient setting. Several observational and interventional trials have investigated the benefits of procalcitonin (PCT) and C-reactive protein (CRP) testing in primary care. Both markers have shown promising results, although CRP is an inflammatory biomarker while PCT is more specific for bacterial infections. For CRP, point-of-care testing is widely established. Recently, sensitive point-of-care testing for PCT has also become available. A high-quality trial comparing these two markers for the management of patients in primary care is currently lacking. The aim of this paper is to review the existing literature investigating the use of PCT and CRP in primary care. The authors compare their performance for guiding antibiotic stewardship and analyze the cut-off values and endpoints to put these parameters into context in a low-acuity environment.