Group C beta hemolytic Streptococci as a potential pathogen in patients presenting with an uncomplicated acute sore throat - a systematic literature review and meta-analysis

Is Streptococcus pyogenes a pathogen or passenger in uncomplicated acute sore throat? A systematic review and meta-analysis

OBJECTIVES

The objective was to estimate the probability that finding a Streptococcus pyogenes (Group A Streptococcus) in a throat swab in a patient with a sore throat reflects the aetiology. We also investigated to what extent this is influenced by age, carrier rates of S. pyogenes and climate zone.

METHODS

We conducted a comprehensive search of Medline and Scopus up until October 2023 for case-control studies reporting the prevalence of S. pyogenes in patients with a sore throat and healthy controls. We only included studies with separate data for children and adults. We used the positive and negative etiologic predictive values (P-EPV and N-EPV) to estimate the probability of a link between a sore throat and a finding of S. pyogenes.

RESULTS

We included 15 studies in our meta-analysis. The overall P-EPV for children and adults were 63% (49-74%) and 92% (87-95%), respectively. The P-EPV rose to 83% (64-93%) for children and 94% (90-97%) for adults when only patients with 3-4 Centor criteria were included. The overall N-EPV was 97% (96-98%) for children and 96% (95-97%) for adults.

CONCLUSION

Detecting S. pyogenes in adult patients with an uncomplicated acute sore throat is useful to rule in S. pyogenes as the likely aetiologic agent. The P-EPV significantly increased for children when those with 3-4 Centor criteria were selected. A negative throat swab is always useful for both children and adults to rule out S. pyogenes as the cause of sore throat.

Duration of severe and moderate symptoms in pharyngitis by cause

OBJECTIVE

This study aimed to assess the cause of acute pharyngitis and determine the duration of severe and moderate symptoms based on the aetiology.

DESIGN

Prospective observational study. SITE: One urban health care centre.

PARTICIPANTS

Patients aged 15 or older with acute pharyngitis were included.

INTERVENTIONS

Bacterial identification was carried out in the microbiology lab using MALDI-TOF in two throat samples. Patients received a symptom diary to return after one week.

MAIN MEASUREMENTS

Number of days with severe symptoms, scoring 5 or more in any of the symptoms included in the symptom diary, and moderate symptoms, scoring 3 or more.

RESULTS

Among the 149 patients recruited, beta-haemolytic streptococcus group A (GABHS) was the most common aetiology. Symptoms and signs alone as well as the mean Centor score cannot distinguish between GABHS and other bacterial causes in patients with acute pharyngitis. However, there was a trend indicating that infections caused by Streptococcus dysgalactiae and Streptococcus agalactiae presented more severe symptoms, whereas infections attributed to the Streptococcus anginosus group, Fusobacterium spp., and those where oropharyngeal microbiota was isolated tended to have milder symptoms. S. dysgalactiae infections showed a trend towards longer severe and moderate symptom duration.

CONCLUSION

GABHS was the most prevalent, but group C streptococcus caused more severe and prolonged symptoms.

Associated Bacterial Coinfections in COVID-19-Positive Patients

Background and Objectives: The aim of this study was to identify specific rhino- and oropharyngeal microbiological pathogens as well as associated comorbidities that favor SARS-CoV-2 infection and corelate them. Materials and Methods: This prospective clinical study enrolled 61 patients (28 COVID-19-positive and 33 controls) who were tested for other comorbidities and co-existence of associated oral pathogenic microbiota. Results: A total of 247 bacterial isolates were identified in the bacterial cultures in both groups. Viral hepatitis type A was more prevalent in the COVID-19-positive group (p = 0.026), as was the presence of oral candidiasis (p = 0.006). In the control group, a moderate direct relationship was observed between the Beta hemolytic streptococcus group G and dermatitis, and strong direct relationships were observed between the Beta hemolytic streptococcus group G and external otitis, Streptococcus pyogenes and dental alveolitis, and Streptococcus pyogenes and chronic lymphocytic leukemia. In the test group, strong direct relationships were observed between Hemophilus influenzae and pulmonary thromboembolism; Staphylococcus aureus and autoimmune thyroiditis; post-viral immunosuppression, chronic coronary syndrome, and hypernatremia; Beta hemolytic streptococcus group C and rheumatoid polyneuropathy; Beta hemolytic streptococcus group G and hyperkalemia, hypothyroidism, secondary anemia, and splenomegaly; and active oral candidiasis and SARS-CoV-2 viral pneumonia. The following relationships were strong, but inverse: Beta hemolytic streptococcus group G and acute respiratory failure, and active oral candidiasis and SARS-CoV-2 viral bronchopneumonia. Conclusions: Briefly, COVID-19-positive patients have the predisposition to build up associated comorbidities and coinfections, which can be the expression of the immune burden that this virus generates to the host.

Bacterial findings in patients referred to hospital for the treatment of acute tonsillitis with or without peritonsillar phlegmon

BACKGROUND

The vast majority of patients with acute tonsillitis (AT) are managed in general practice. However, occasionally patients are referred to hospital for specialized management because of aggravated symptoms and/or findings suggestive of peritonsillar involvement. No prospective studies have been conducted aiming to investigate the prevalent and significant microorganisms in this highly selected group of patients. We aimed to describe the microbiological findings of acute tonsillitis with or without peritonsillar phlegmon (PP) in patients referred for hospital treatment and to point out potential pathogens using the following principles to suggest pathogenic significance: (1) higher prevalence in patients compared to healthy controls, (2) higher abundance in patients compared to controls, and (3) higher prevalence at time of infection compared to time of follow up.

METHODS

Meticulous and comprehensive cultures were performed on tonsillar swabs from 64 patients with AT with (n = 25) or without (n = 39) PP and 55 healthy controls, who were prospectively enrolled at two Danish Ear-Nose-Throat Departments between June 2016 and December 2019.

RESULTS

Streptococcus pyogenes was significantly more prevalent in patients (27%) compared to controls (4%) (p < 0.001). Higher abundance was found in patients compared to controls for Fusobacterium necrophorum (mean 2.4 vs. 1.4, p = 0.017) and S. pyogenes (mean 3.1 vs. 2.0, p = 0.045) in semi-quantitative cultures. S. pyogenes, Streptococcus dysgalactiae, and Prevotella species were significantly more prevalent at time of infection compared to follow up (p = 0.016, p = 0.016, and p = 0.039, respectively). A number of species were detected significantly less frequently in patients compared to controls and the mean number of species was significantly lower in patients compared to controls (6.5 vs. 8.3, p < 0.001).

CONCLUSIONS

Disregarding Prevotella spp. because of the prevalence in healthy controls (100%), our findings suggest that S. pyogenes, F. necrophorum, and S. dysgalactiae are significant pathogens in severe AT with or without PP. In addition, infections were associated with reduced diversity (dysbacteriosis).

TRIAL REGISTRATION

The study is registered in the ClinicalTrials.gov protocol database (# 52,683). The study was approved by the Ethical Committee at Aarhus County (# 1-10-72-71-16) and by the Danish Data Protection Agency (# 1-16-02-65-16).

Best management of patients with an acute sore throat – a critical analysis of current evidence and a consensus of experts from different countries and traditions

BACKGROUND

There is a very large body of publications discussing the management of patients with an acute sore throat. Advocates for a restrictive antibiotic policy and advocates for a more liberal use of antibiotics emphasise different and valid arguments and to date have not been able to unite in a consensus. Contradicting guidelines based on the same body of knowledge is not logical, may cause confusion and cause unwanted variation in clinical management.

METHODS

In multiple video meetings and email correspondence from March to November 2022 and finally in a workshop at the annual meeting for the North American Primary Care Group in November 2022, experts from different countries representing different traditions agreed on how the current evidence should be interpreted.

RESULTS

This critical analysis identifies that the problem can be resolved by introducing a new triage scheme considering both the acute risk for suppurative complications and sepsis as well as the long-term risk of developing rheumatic fever.

CONCLUSIONS

The new triage scheme may solve the long-standing problem of advocating for a restrictive use of antibiotics while also satisfying concerns that critically ill patients might be missed with severe consequences. We acknowledge that the perspective of this problem is vastly different between high- and low-income countries. Furthermore, we discuss the new trend which allows nurses and pharmacists to independently manage these patients and the increased need for safety netting required for such management.

Associations Between Findings of Fusobacterium necrophorum or β-Hemolytic Streptococci and Complications in Pharyngotonsillitis-A Registry-Based Study in Southern Sweden

BACKGROUND

Most pharyngotonsillitis guidelines focus on the identification of group A streptococci (GAS), guided by clinical scores determining whom to test with a rapid antigen detection test. Nevertheless, many patients testing negative with this test are evaluated for group C/G streptococci (GCS/GGS) and Fusobacterium necrophorum, yet their importance remains debated. Our primary aim was to evaluate associations between complications and findings of F. necrophorum, GAS, or GCS/GGS in pharyngotonsillitis.

METHODS

This was a retrospective, registry-based study of pharyngotonsillitis cases tested for F. necrophorum (polymerase chain reaction) and β-hemolytic streptococci (culture) in the Skåne Region, Sweden, in 2013-2020. Patients with prior complications or antibiotics (within 30 days) were excluded. Data were retrieved from registries and electronic charts. Logistic regression analyses were performed with a dichotomous composite outcome of complications as primary outcome, based on International Classification of Diseases, Tenth Revision, codes. Cases with negative results (polymerase chain reaction and culture) were set as reference category. Complications within 30 days were defined as peritonsillar or pharyngeal abscess, otitis, sinusitis, sepsis or septic complications, recurrence of pharyngotonsillitis (after 15-30 days) or hospitalization.

RESULTS

Of 3700 registered cases, 28% had F. necrophorum, 13% had GCS/GGS, 10% had GAS, and 54% had negative results. The 30-day complication rates were high (20%). F. necrophorum (odds ratio, 1.8; 95% confidence interval, 1.5-2.1) and GAS (1.9; 1.5-2.5) were positively associated with complications, whereas GCS/GGS were negatively associated (0.7; 0.4-0.98).

CONCLUSIONS

Our results indicate that F. necrophorum is a relevant pathogen in pharyngotonsillitis, whereas the relevance of testing for GCS/GGS is questioned. However, which patient to test and treat for F. necrophorum remains to be defined.

What is the optimal strategy for managing primary care patients with an uncomplicated acute sore throat? Comparing the consequences of nine different strategies using a compilation of previous studies

OBJECTIVE

Identifying optimal strategies for managing patients of any age with varying risk of acute rheumatic fever (ARF) attending for an apparently uncomplicated acute sore throat, also clarifying the role of point-of-care testing (POCT) for presence of group A beta-haemolytic Streptococcus (GABHS) in these settings.

DESIGN

We compared outcomes of adhering to nine different strategies for managing these patients in primary healthcare.

SETTING AND PARTICIPANTS

The nine strategies, similar to guidelines from several countries, were tested against two validation data sets being constructs from seven prior studies.

MAIN OUTCOME MEASURES

The proportion of patients requiring a POCT, prescribed antibiotics, prescribed antibiotics having GABHS and finally having GABHS not prescribed antibiotics, if different strategies had been adhered to.

RESULTS

In a scenario with high risk of ARF, adhering to existing guidelines would risk many patients ill from GABHS left without antibiotics. Hence, using a POCT on all of these patients minimised their risk. For low-risk patients, it is reasonable to only consider antibiotics if the patient has more than low pain levels despite adequate analgesia, 3-4 Centor scores (or 2-3 FeverPAIN scores or 3-4 McIsaac scores) and a POCT confirming the presence of GABHS. This would require testing only 10%-15% of patients and prescribing antibiotics to only 3.5%-6.6%.

CONCLUSIONS

Patients with high or low risk for ARF needs to be managed very differently. POCT can play an important role in safely targeting the use of antibiotics for patients with an apparently uncomplicated acute sore throat.

Association between bacterial finding, antibiotic treatment and clinical course in patients with pharyngotonsillitis: a registry-based study in primary healthcare in Sweden

Background

The role of non-group A streptococci and Fusobacterium necrophorum in pharyngotonsillitis has been disputed and few prospective studies have evaluated the effect of antibiotic treatment. This study uses registry data to investigate the relation between antibiotic prescription for pharyngotonsillitis in primary healthcare and return visits for pharyngotonsillitis, complications, and tonsillectomy.

Methods

Retrospective data were extracted from the regional electronic medical record system in Kronoberg County, Sweden, for all patients diagnosed with pharyngotonsillitis between 2012 and 2016. From these data, two cohorts were formed: one based on rapid antigen detection tests (RADT) for group A streptococci (GAS) and one based on routine throat cultures for β-haemolytic streptococci and F. necrophorum. The 90 days following the inclusion visit were assessed for new visits for pharyngotonsillitis, complications, and tonsillectomy, and related to bacterial aetiology and antibiotic prescriptions given at inclusion.

Results

In the RADT cohort (n = 13,781), antibiotic prescription for patients with a positive RADT for GAS was associated with fewer return visits for pharyngotonsillitis within 30 days compared with no prescription (8.7% vs. 12%; p = 0.02), but not with the complication rate within 30 days (1.5% vs. 1.8%; p = 0.7) or with the tonsillectomy rate within 90 days (0.27% vs. 0.26%; p = 1). In contrast, antibiotic prescription for patients with a negative RADT was associated with more return visits for pharyngotonsillitis within 30 days (9.7% vs. 7.0%; p = 0.01). In the culture cohort (n = 1 370), antibiotic prescription for patients with Streptococcus dysgalactiae ssp. equisimilis was associated with fewer return visits for pharyngotonsillitis within 30 days compared with no prescription (15% vs. 29%; p = 0.03).

Conclusions

Antibiotic prescription was associated with fewer return visits for pharyngotonsillitis in patients with a positive RADT for GAS but with more return visits in patients with a negative RADT for GAS. There were no differences in purulent complications related to antibiotic prescription.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06511-y.

Acute sore throat and Fusobacterium necrophorum in primary healthcare: a systematic review and meta-analysis

PURPOSE

The main objective of this review was to describe and quantify the association between Fusobacterium necrophorum (FN) and acute sore throat in primary healthcare (PHC).

METHODS

In this systematic review and meta-analysis, we searched Scopus and PubMed for case-control studies reporting the prevalence of FN in patients attending primary care for an uncomplicated acute sore throat as well as in healthy controls. Only studies published in English were considered. Publications were not included if they were case studies, or if they included patients prescribed antibiotics before the throat swab, patients with a concurrent malignant disease, on immunosuppression, having an HIV infection, or patients having another acute infection in addition to a sore throat. Inclusion criteria and methods were specified in advance and published in PROSPERO. The primary outcome was positive etiologic predictive value (P-EPV), quantifying the probability for an association between acute sore throat and findings of FN in the pharynx. For comparison, our secondary outcome was the corresponding P-EPV for group A Streptococcus (GAS).

RESULTS

PubMed and Scopus yielded 258 and 232 studies, respectively. Removing duplicates and screening the abstracts resulted in 53 studies subsequently read in full text. For the four studies of medium to high quality included in the meta-analysis, the cumulative P-EPV regarding FN was 64% (95% CI 33% to 83%). GAS, based on data from the same publications and patients, yielded a positive EPV of 93% (95% CI 83% to 99%).

CONCLUSIONS

The results indicate that FN may play a role in PHC patients with an acute sore throat, but the association is much weaker compared with GAS.