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 value (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.

CONCLUSIONS

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 the sore throat.

The rise and fall of acute rheumatic fever and rheumatic heart disease: a mini review

Introduction

The incidences of acute rheumatic fever (ARF) and rheumatic heart disease (RHD), which were leading causes of death in children in the 1920s, have decreased substantially. Considering the recent resurgence of scarlet fever and increased incidence of streptococcal pharyngitis in children, an investigation of the current status of ARF and RHD may be worthwhile.

Objective

To summarize the prevalence trends, pathogenic factors, and prevention strategies for ARF and RHD in children.

Methods

A selective search of literature published between January 1920 and February 2023 was done in PubMed, using the terms "acute rheumatic fever", "rheumatic heart disease", "group A Streptococcus", "pharyngitis", "pharyngeal tonsillitis", "scarlet fever", "impetigo", "obstructive sleep apnea syndrome" and "child".

Results

Overcrowded homes and inadequate sanitation led to recurrent group A streptococcal infection, and the causal relationship between group A streptococcal infection and ARF/RHD was well established. Streptococcal infectious diseases, such as group A streptococcal pharyngeal tonsillitis, SF, impetigo, and obstructive sleep apnea syndrome, were associated with the occurrence of ARF and RHD. ARF and RHD were still prevalent in young people of developing countries and economically poor populations of high-income countries. Universal disease registration systems were critical to locating disease outbreaks, tracking disease transmission, and identifying high-risk populations. Four-level prevention strategies were effective in reducing the incidence and mortality of ARF and RHD.

Conclusions

Registry and preventive measures for ARF and RHD should be strengthened in areas of dense population; poor sanitation; resurgence of SF; and high incidence of streptococcal pharyngitis, impetigo, and obstructive sleep apnea syndrome.

Asymptomatic pharyngeal carriage rate of Streptococcus pyogenes, its associated factors and antibiotic susceptibility pattern among school children in Hawassa town, southern Ethiopia

Objectives

The aim of this study was to determine the asymptomatic pharyngeal carriage rate of S. pyogenes, antimicrobial pattern and related risk factors among school children in Hawassa, southern Ethiopia.

Results

Out of 287 school children’s screened, 35 (12.2%) were colonized with S. pyogenes. The carriage rate was significantly associated with factors such as sex (female p = 0.013) occupational status of mother (p = 0.002), lower income source (500–900 ETB, 1000–1500 ETB) (p = 0.001, and p = 0.042), history of hospitalization (p = 0.00) and residence of the children (p = 0.002). High level resistant to tetracycline and low level to vancomycin were observed, while penicillin, amoxicillin, erythromycin, chloramphenicol, and ceftriaxone were found to be effective.

Molecular epidemiology and genomics of group A Streptococcus

Streptococcus pyogenes (group A Streptococcus; GAS) is a strict human pathogen with a very high prevalence worldwide. This review highlights the genetic organization of the species and the important ecological considerations that impact its evolution. Recent advances are presented on the topics of molecular epidemiology, population biology, molecular basis for genetic change, genome structure and genetic flux, phylogenomics and closely related streptococcal species, and the long- and short-term evolution of GAS. The application of whole genome sequence data to addressing key biological questions is discussed.

Molecular characterization of Streptococcus pyogenes group A isolates from a tertiary hospital in Lebanon

Streptococcus pyogenes [Group A Streptococcus (GAS)] is one of the most important human pathogens, responsible for numerous diseases with diverse clinical manifestations. As the epidemiology of GAS infections evolves, a rapid and reliable characterization of the isolates remains essential for epidemiological analysis and infection control. This study investigated the epidemiological patterns and genetic characteristics of 150 GAS isolates from a tertiary hospital in Lebanon by emm typing, superantigens (SAgs) detection, PFGE and antibiotic profiling. The results revealed 41 distinct emm types, the most prevalent of which were emm89 (16 %), emm12 (10 %), emm2 (9 %) and emm1 (8 %). Testing for the presence of superantigens showed that speB (87 %), ssa (36 %) and speG (30 %) were predominant. PFGE detected 39 pulsotypes when a similarity cut-off value of 80 % was implemented. Antibiotic-susceptibility testing against seven different classes of antibiotics showed that 9 % of the isolates were resistant to clindamycin, 23 % were resistant to erythromycin and 4 % showed the macrolide-lincosamide-streptogramin B (MLSB) phenotype. The emergence of tetracycline-resistant strains (37 %) was high when compared with previous reports from Lebanon. This study provided comprehensive evidence of the epidemiology of GAS in Lebanon, highlighting the association between emm types and toxin genes, and providing valuable information about the origin and dissemination of this pathogen.

Prevalence of Group A beta-haemolytic Streptococcus isolated from children with acute pharyngotonsillitis in Aden, Yemen

OBJECTIVES

To estimate the prevalence of Group A beta-haemolytic streptococcus (GAS) and non-GAS infections among children with acute pharyngotonsillitis in Aden, Yemen, to evaluate the value of a rapid diagnostic test and the McIsaac score for patient management in this setting and to determine the occurrence of emm genotypes among a subset of GAS isolated from children with acute pharyngotonsillitis and a history of acute rheumatic fever (ARF) or rheumatic heart disease (RHD).

METHODS

Group A beta-haemolytic streptococcus infections in school-aged children with acute pharyngotonsillitis in Aden, Yemen, were diagnosed by a rapid GAS antigen detection test (RADT) and/or GAS culture from a throat swab. The RADT value and the McIsaac screening score for patient management were evaluated. The emm genotype of a subset of GAS isolates was determined.

RESULTS

Group A beta-haemolytic streptococcus pharyngotonsillitis was diagnosed in 287/691 (41.5%; 95% CI 37.8-45.3) children. Group B, Group C and Group G beta-haemolytic streptococci were isolated from 4.3% children. The RADT had a sensitivity of 238/258 (92.2%) and specificity of 404/423 (95.5%) against GAS culture. A McIsaac score of ≥4 had a sensitivity of 93% and a specificity of 82% for confirmed GAS infection. The emm genotypes in 21 GAS isolates from children with pharyngitis and a history of ARF and confirmed RHD were emm87 (11), emm12 (6), emm28 (3) and emm5 (1).

CONCLUSION

This study demonstrates a very high prevalence of GAS infections in Yemeni children and the value of the RADT and the McIsaac score in this setting. More extensive emm genotyping is necessary to understand the local epidemiology of circulating strains.

Epidemiological markers of Streptococcus pyogenes strains in Tunisia

To further understand the epidemiology of Streptococcus pyogenes or group A streptococcus (GAS) infections in Tunisia, phenotypic and genomic markers of GAS isolates, including antibiotic susceptibility, biotypes, T and emm types and toxin gene profiles, have been characterized. A total of 103 isolates, collected between 2000 and 2006, were investigated; 47 were recovered from invasive infections, and 56 from non-invasive infections. Rates of resistance to tetracycline, erythromycin, clindamycin and rifampin were 70.8%, 4.8%, 4.8% and 0.9%, respectively. High levels of resistance to streptomycin and kanamycin were observed in 1.9% and 4.8% of isolates, respectively. Biotype 3 was most common. Twenty different T patterns were observed, with a predominance of T3/13/B3264, and 38 different emm types. In both invasive and non-invasive isolates, emm118 (9.7%), emm42 (8.7%), emm1 (7.8%), st432 (6.8%), emm28 (5.8%) and emm76 (5.8%) were the most prevalent types; emm1, emm76 and emm18 were mainly observed among invasive infections, whereas emm118 (12.5%), emm42 (10.7%) and emm28 (8.9%) were predominant among non-invasive infections. The speB gene was detected in all isolates, but there were variable frequencies of speA, speC and ssa (20.3%, 32% and 25.2% respectively). Significant associations of emm1, emm18 and emm3 with speA and of emm4 and st432 with ssa were found. This first report from Tunisia revealed a unique emm distribution of GAS that differs from those of other regions. This information on the distribution of such emm types will be useful for the development of an appropriate vaccine in a country where the incidence of rheumatic fever remains high.