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Streptococcus pyogenes (Group A Streptococcus, GAS) is a human-restricted pathogen that causes a wide range of diseases from pharyngitis and scarlet fever to more severe, invasive infections such as necrotising fasciitis and streptococcal toxic shock syndrome. There has been a global increase in both scarlet fever and invasive infections during the COVID-19 post-pandemic period. The aim of this study was the molecular characterisation of 17 invasive and non-invasive clinical non-emm1 GAS isolates from an Australian tertiary hospital collected between 2021 and 2022. Whole genome sequencing revealed a total of nine different GAS emm types with the most prevalent being emm22, emm12 and emm3 (each 3/17, 18%). Most isolates (14/17, 82%) carried at least one superantigen gene associated with contemporary scarlet fever outbreaks, and the carriage of these toxin genes was non-emm type specific. Several mutations within key regulatory genes were identified across the different GAS isolates, which may be linked to an increased expression of several virulence factors. This study from a single Australian centre provides a snapshot of non-emm1 GAS clinical isolates that are multiclonal and linked with distinct epidemiological markers commonly observed in high-income settings. These findings highlight the need for continual surveillance to monitor genetic markers that may drive future outbreaks. [ABSTRACT FROM AUTHOR]

A statewide genomic surveillance system for invasive Group A Streptococcus was implemented in Arizona in June 2019, resulting in 1046 isolates being submitted for genomic analysis to characterize emm types and identify transmission clusters. Eleven of the 32 identified distinct emm types comprised >80% of samples, with 29.7% of all isolates being typed as emm 49 (and its genetic derivative emm 151). Phylogenetic analysis initially identified an emm 49 genomic cluster of 4 isolates that rapidly expanded over subsequent months (June 2019 to February 2020). Public health investigations identified epidemiologic links with 3 different long-term care facilities, resulting in specific interventions. Unbiased genomic surveillance allowed for identification and response to clusters that would have otherwise remained undetected. [ABSTRACT FROM AUTHOR]

Streptococcus pyogenes (Group A Streptococcus, GAS) is a human-restricted pathogen that causes a wide range of diseases from pharyngitis and scarlet fever to more severe, invasive infections such as necrotising fasciitis and streptococcal toxic shock syndrome. There has been a global increase in both scarlet fever and invasive infections during the COVID-19 post-pandemic period. The aim of this study was the molecular characterisation of 17 invasive and non-invasive clinical non-emm1 GAS isolates from an Australian tertiary hospital collected between 2021 and 2022. Whole genome sequencing revealed a total of nine different GAS emm types with the most prevalent being emm22, emm12 and emm3 (each 3/17, 18%). Most isolates (14/17, 82%) carried at least one superantigen gene associated with contemporary scarlet fever outbreaks, and the carriage of these toxin genes was non-emm type specific. Several mutations within key regulatory genes were identified across the different GAS isolates, which may be linked to an increased expression of several virulence factors. This study from a single Australian centre provides a snapshot of non-emm1 GAS clinical isolates that are multiclonal and linked with distinct epidemiological markers commonly observed in high-income settings. These findings highlight the need for continual surveillance to monitor genetic markers that may drive future outbreaks.

ABSTRACT Streptococcus pyogenes is a leading cause of human morbidity and mortality, especially in resource-limited settings. The development of a vaccine against S. pyogenes is a global health priority to reduce the burden of postinfection rheumatic heart disease. To support this, molecular characterization of circulating S. pyogenes isolates is needed. We performed whole-genome analyses of S. pyogenes isolates from skin and soft tissue infections in Sukuta, The Gambia, a low-income country (LIC) in West Africa where there is a high burden of such infections. To act as a comparator to these LIC isolates, skin infection isolates from Sheffield, United Kingdom (a high-income country [HIC]), were also sequenced. The LIC isolates from The Gambia were genetically more diverse (46 emm types in 107 isolates) than the HIC isolates from Sheffield (23 emm types in 142 isolates), with only 7 overlapping emm types. Other molecular markers were shared, including a high prevalence of the skin infection-associated emm pattern D and the variable fibronectin-collagen-T antigen (FCT) types FCT-3 and FCT-4. Fewer of the Gambian LIC isolates carried prophage-associated superantigens (64%) and DNases (26%) than did the Sheffield HIC isolates (99% and 95%, respectively). We also identified streptococcin genes unique to 36% of the Gambian LIC isolates and a higher prevalence (48%) of glucuronic acid utilization pathway genes in the Gambian LIC isolates than in the Sheffield HIC isolates (26%). Comparison to a wider collection of HIC and LIC isolate genomes supported our findings of differing emm diversity and prevalence of bacterial factors. Our study provides insight into the genetics of LIC isolates and how they compare to HIC isolates. IMPORTANCE The global burden of rheumatic heart disease (RHD) has triggered a World Health Organization response to drive forward development of a vaccine against the causative human pathogen Streptococcus pyogenes. This burden stems primarily from low- and middle-income settings where there are high levels of S. pyogenes skin and soft tissue infections, which can lead to RHD. Our study provides much needed whole-genome-based molecular characterization of isolates causing skin infections in Sukuta, The Gambia, a low-income country (LIC) in West Africa where infection and RHD rates are high. Although we identified a greater level of diversity in these LIC isolates than in isolates from Sheffield, United Kingdom (a high-income country), there were some shared features. There were also some features that differed by geographical region, warranting further investigation into their contribution to infection. Our study has also contributed data essential for the development of a vaccine that would target geographically relevant strains.

Abstract Background Group A streptococcus (GAS) is an important human pathogen responsible for a broad range of infections. Epidemiological surveillance has been crucial to detect changes in the geographical and temporal variation of the disease pattern. The objective of this study was to investigate the molecular epidemiological characteristics and antimicrobial resistance of GAS isolates from patients in Children’s Hospital in Beijing. Methods From 2016 to 2017, pharyngeal swab samples were collected from the outpatients in Children’s Hospital, Capital Institute of Pediatrics, who were diagnosed with scarlet fever. Antimicrobial susceptibility test was performed according to the distribution of conventional antibiotics and Clinical and Laboratory Standards Institute (CLSI) recommendations. The distribution of the macrolide-resistance genes (ermB, ermA, mefA), emm (M protein-coding gene) typing, and superantigens (SAg) gene profiling were examined by polymerase chain reaction (PCR). Results A total of 297 GAS isolates were collected. The susceptibility of the isolates to penicillin, ceftriaxone, and levofloxacin was 100%. The resistance rate to erythromycin and clindamycin was 98.3 and 96.6%, respectively. The dominant emm types were emm12 (65.32%), emm1 (27.61%), emm75 (2.69%), and emm89 (1.35%). Of the 297 isolates, 290 (97.64%) carried the ermB gene, and 5 (1.68%) carried the mefA gene, while none carried the ermA gene. The most common superantigen genes identified from GAS isolates were smeZ (96.97%), speC (92.59%), speG (91.58%), ssa (85.52%), speI (54.55%), speH (52.19%), and speA (34.34%). Isolates with the genotype emm1 possessed speA, speC, speG, speJ, speM, ssa, and smeZ, while emm12 possessed speC, speG, speH, speI, speM, ssa, and smeZ superantigens. Conclusions The prevalent strain of GAS isolates in Beijing has a high resistance rate to macrolides; however, penicillin can still be the preferred antibiotic for treatment. Erythromycin resistance was predominantly mediated by ermB. The common emm types were emm12 and emm1. There was a correlation between emm and the superantigen gene. Thus, long-term monitoring and investigation of the emm types and superantigen genes of GAS prevalence are imperative.

Background: Streptococcus dysgalactiae subsp equisimilis (SDSE) is an emerging pathogen causing pharyngitis and post-streptococcal sequelae like S. pyogenes. SDSE was initially considered a commensal microorganism inhabiting the upper respiratory tract and skin. However, recently it has gained attention due to an increase in the invasive SDSE infections, which were reported in the early 20th century., Objectives: The aim of this review is to bring awareness of SDSE in the medical microbiologists because often its ignorance leads to the under reporting or misdiagnosis of SDSE. This also highlights the clinical spectrum of infections and the molecular epidemiology of SDSE., Content: Diagnosis of SDSE in clinical laboratories is challenging, because SDSE can be seen expressing either of the three Lancefield antigen Groups, Group A, C, and G. While MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight) is a discriminatory method for identifying SDSE, its high cost can limit its use in many laboratories. Currently, there is limited data on SDSE, and further studies are required to associate the disease outcome and the emm type/ST of SDSE in India and other developing countries. This review highlights the importance of recognizing SDSE as an emerging pathogen, and to screen for SDSE in infections similar to S.pyogenes, especially in regions such as India with a high incidence of Streptococcal diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)

BackgroundGroup A streptococcus (GAS) causes invasive disease, superficial disease, and can asymptomatically colonize humans. Superantigens are one virulence factor found in GAS. Previous studies found associations between the genes that encode superantigens and emm type of GAS. It is unknown if these associations are due to underlying biological factors that limit the distribution of superantigens or, alternatively, if these associations are due to the expansion of local GAS linages where these studies took place. To further address this question we screened GAS isolates collected from Salvador, Brazil for 11 known superantigen genes.MethodsSeventy-seven GAS isolates were screened by PCR for superantigen genes. These superantigen genes were speA, speC, speG, speH, speI, speJ, speK, speL, speM, ssa, and smeZ. We used Fisher's two-sided exact test to identify associations between superantigens and GAS emm type. We then compared our results to previous reports of superantigen prevalence and superantigen association with emm type.ResultsIn our collection we found several emm type and superantigen genotype combinations that have previously been reported in isolates from Europe and Australia. We also found that speA was significantly associated with emm type 1, and that speC was significantly associated with emm type 12.ConclusionsOur study reports superantigen genotypes of GAS from a region of the world that is lacking this information. We found evidence of common GAS superantigen genotypes that are spread worldwide as well as novel superantigen genotypes that, so far, are unique to Brazil.

As a potential side effect of the severe acute respiratory syndrome coronavirus type 2 pandemic, invasive group A Streptococcus (iGAS) infections in Europe have increased dramatically in both children and adults in the end of 2022. This epidemiological and molecular study describes the distributions of streptococcal genes encoding the M antigen ( emm types) and superantigens in patients with invasive and non-invasive GAS infections. From December 2022 to December 2023, a total of 163 GAS isolates were collected from sterile and non-sterile sites of patients at five hospitals in Germany including two tertiary care centers. Genes encoding M protein and superantigens were determined following the guidelines of CDC Streptococcus laboratory. Patients' characteristics were reviewed retrospectively. Correlations of clinical factors, emm types, and superantigens with rates of invasive infections were analyzed. Of the 163 included GAS cases, 112 (69%) were considered as invasive. In total, 33 different emm types were observed, of which emm1.0 ( n = 49; 30%), emm89.0 ( n = 15; 9%), and emm12.0 ( n = 14; 9%) were most prevalent. In total, 70% of emm1.0 isolates belonged to M1 UK lineage. No difference in invasive infections was observed for the M1 UK lineage compared with other emm1.0 isolates. However, the emm1.0 type, presence of speA1-3 , speG , or speJ , as well as adulthood were significantly associated with invasive infections. In contrast, emm12.0 isolates were significantly less associated with invasive infections. Multivariable analysis confirmed a significant influence of speJ and adulthood on iGAS infections. This study underlines the importance of continuous monitoring of genomic trends and identification of emerging GAS variants. This may aid in delineating pathogenicity factors of Streptococcus pyogenes that propel invasive infections., Competing Interests: The authors declare no conflict of interest.

Our study aimed to investigate the epidemiological and molecular characteristics of isolates collected from Group A Streptococcus (GAS) infections in children in Beijing China during the year 2019. Emm typing, superantigens, and erythromycin resistance genotypes were determined by PCR. Antimicrobial susceptibility testing was performed as recommended by Clinical Laboratory Standards Institute (CLSI). A total of 271 GAS isolates were collected. Thirteen different emm types, including 31 subtypes, were identified. The most prevalent emm types were emm12 (52.77%), emm1 (36.9%), emm3.1 (2.95%), and emm75.0 (2.95%). Two variant subtypes, STC36.0 and STG840.2, were identified. There was no difference in the portion of emm12 and emm1 isolates in scarlet fever, impetigo, and psoriasis. The majority of superantigens detected were smeZ (94.46%), speC (91.14%), and ssa (74.91%), followed by speH (56.46%), speI (45.76%), speJ (36.9%), and speA (34.32%). More scarlet fever isolates harbored speA (35.6%) and speJ (38.4%), more psoriasis isolates harbored speI (57.9%), and more impetigo isolates harbored ssa (89.7%). Isolates were universally susceptible to penicillin and resistant to erythromycin (94.83%). Moreover, 89.67% erythromycin resistance isolates harbored the ermB gene. The erythromycin resistance rate of the isolates from the three diseases was different. Scarlet fever is the common streptococcal infectious disease in dermatology. Emm12 and emm1 were the most prevalent emm types. The most prevalent superantigens detected were smeZ, spec, and ssa. There is association between diversity of superantigens and disease manifestation. Hence, continuous surveillance of GAS molecular epidemiological characterizations in different diseases is needed. [ABSTRACT FROM AUTHOR]

Background: Group A streptococcus (GAS) is an important human pathogen responsible for a broad range of infections. Epidemiological surveillance has been crucial to detect changes in the geographical and temporal variation of the disease pattern. The objective of this study was to investigate the molecular epidemiological characteristics and antimicrobial resistance of GAS isolates from patients in Children's Hospital in Beijing.Methods: From 2016 to 2017, pharyngeal swab samples were collected from the outpatients in Children's Hospital, Capital Institute of Pediatrics, who were diagnosed with scarlet fever. Antimicrobial susceptibility test was performed according to the distribution of conventional antibiotics and Clinical and Laboratory Standards Institute (CLSI) recommendations. The distribution of the macrolide-resistance genes (ermB, ermA, mefA), emm (M protein-coding gene) typing, and superantigens (SAg) gene profiling were examined by polymerase chain reaction (PCR).Results: A total of 297 GAS isolates were collected. The susceptibility of the isolates to penicillin, ceftriaxone, and levofloxacin was 100%. The resistance rate to erythromycin and clindamycin was 98.3 and 96.6%, respectively. The dominant emm types were emm12 (65.32%), emm1 (27.61%), emm75 (2.69%), and emm89 (1.35%). Of the 297 isolates, 290 (97.64%) carried the ermB gene, and 5 (1.68%) carried the mefA gene, while none carried the ermA gene. The most common superantigen genes identified from GAS isolates were smeZ (96.97%), speC (92.59%), speG (91.58%), ssa (85.52%), speI (54.55%), speH (52.19%), and speA (34.34%). Isolates with the genotype emm1 possessed speA, speC, speG, speJ, speM, ssa, and smeZ, while emm12 possessed speC, speG, speH, speI, speM, ssa, and smeZ superantigens.Conclusions: The prevalent strain of GAS isolates in Beijing has a high resistance rate to macrolides; however, penicillin can still be the preferred antibiotic for treatment. Erythromycin resistance was predominantly mediated by ermB. The common emm types were emm12 and emm1. There was a correlation between emm and the superantigen gene. Thus, long-term monitoring and investigation of the emm types and superantigen genes of GAS prevalence are imperative. [ABSTRACT FROM AUTHOR]

Group A streptococcus (GAS) is a human pathogen causing a broad range of infections, linked with global morbidity and mortality. Macrolide resistance rates vary significantly in different parts of the world. Driving factors of the emergence and spread of resistant clones are not clearly understood. We investigated 102 macrolide-resistant GAS strains collected during the period 2014–2018 from various clinical specimens from Bulgarian patients. Strains were characterized by the presence of mefA/mefE, ermA , and ermB using polymerase chain reaction and sequencing for mefA/mefE. Resistant strains were studied by emm sequence typing and emm -cluster system. Most prevalent emm types among the macrolide-resistant GAS strains were emm 28 (22.55%), emm 12 (17.65%), and emm 4 (16.66%). Almost all (87.25%) of the macrolide-resistant isolates harboring ermB were emm 28. The isolates that carried ermA were predominantly emm 12 (38.24%) and emm 77 (38.24%), with fewer emm 89 (23.53%). The isolates harbored predominantly mefE (49 isolates) and only 9 strains carried mefA. The most prevalent emm clusters among the GAS isolates were E4 (40.20%), A-C4 (17.65%), and E1 (16.66%). The study's results suggest that dissemination of specific clones in GAS population may also be the reason for the increasing macrolide-resistance rate in our country. [ABSTRACT FROM AUTHOR]

BackgroundStreptococcus pyogenes or group A streptococcus (GAS) is an important human pathogen responsible for a broad range of infections, from uncomplicated to more severe and invasive diseases with high mortality and morbidity. Epidemiological surveillance has been crucial to detect changes in the geographical and temporal variation of the disease pattern; for this purpose the M protein gene (emm) gene typing is the most widely used genotyping method, with more than 200 emm types recognized. Molecular epidemiological data have been also used for the development of GAS M protein-based vaccines.MethodsThe aim of this paper was to provide an updated scenario of the most prevalent GAS emm types responsible for invasive infections in developed countries as Europe and North America (US and Canada), from 1st January 2000 to 31st May 2017. The search, performed in PubMed by the combined use of the terms (“emm”) and (“invasive”) retrieved 264 articles, of which 38 articles (31 from Europe and 7 from North America) met the inclusion criteria and were selected for this study. Additional five papers cited in the European articles but not retrieved by the search were included.Resultsemm1 represented the dominant type in both Europe and North America, replaced by other emm types in only few occasions. The seven major emm types identified (emm1, emm28, emm89, emm3, emm12, emm4, and emm6) accounted for approximately 50–70% of the total isolates; less common emm types accounted for the remaining 30–50% of the cases. Most of the common emm types are included in either one or both the 26-valent and 30-valent vaccines, though some well-represented emm types found in Europe are not.ConclusionThis study provided a picture of the prevalent emm types among invasive GAS (iGAS) in Europe and North America since the year 2000 onward. Continuous surveillance on the emm-type distribution among iGAS infections is strongly encouraged also to determine the potential coverage of the developing multivalent vaccines.

Biofilm formation has been well known as a determinant of bacterial virulence. Group G Streptococcus dysgalactiae subspecies equisimilis ( SDSE), a relevant pathogen with increasing medical importance, was evaluated for the biofilm-forming potential. Microtiter plate assay was used to assess the most feasible medium for group G SDSE to form a biofilm. Among 246 SDSE isolates examined, 46.7%, 43.5%, 33.3%, and 26.4% of isolates showed moderate or strong biofilm-forming abilities using tryptic soy broth ( TSB), brain heart infusion broth ( BHI), Todd-Hewitt broth ( THB), and C medium with 30 mM glucose ( CMG), respectively. The addition of glucose significantly increased the biofilm-forming ability of group G SDSE. FCT (fibronectin-collagen-T-antigen) typing of SDSE was first undertaken and 11 FCT types were found. Positive associations of stG10.0 or negative associations of stG245.0, stG840.0, and stG6.1 with biofilm-forming ability of SDSE were, respectively, found. This was the first investigation demonstrating biofilm-forming potential in clinical group G SDSE isolates; also, some significant associations of biofilm-forming ability with certain emm types were presented. [ABSTRACT FROM AUTHOR]

Introduction: In penicillin allergic patients, macrolides are the most commonly used antibiotics for treating streptococcal infections, irrespective of the higher resistance rates. The objective of this study was to evaluate the comparative prevalence, phenotypes, and genetic determinants of macrolide resistance and associated emm types among different clinical isolates of Streptococcus pyogenes. Methodology: A total of 173 Streptococcus pyogenes isolates were examined for macrolide resistance phenotype by double-disc test, resistance determinants by multiplex PCR and emm genotyping. Results: Erythromycin resistance was found in 51.4% of isolates, with MIC90 = 256 µg/mL Inducible phenotype was commonly found (iMLS, 67.4%) followed by the M phenotype (32.5%). Among these isolates, 65.1% harboured ermB and 32.5% mefA as sole macrolide resistance gene, whereas presence of both, ermB plus mefA was observed in 2.2% cases. The most common types among resistant strains were emm63 (11.2%), emm44 (6.7%), emm42 (5.6%), and emm75.3, emm82, emm85, emm92, emm111.1 (4.4% each). Statistically significant association was observed between emm63, emm44 and erythromycin resistance (p ≤ 0.05). Association of these emm types and macrolide resistance have not been reported earlier. Conclusion: Higher macrolide resistance in this study can be attributed to overuse and misuse of this antibiotic. These findings indicate that macrolides should not be empirically used for treating severe streptococcal infections. [ABSTRACT FROM AUTHOR]

We aimed to assess the effect of invasive group A streptococcal (GAS) infection and the potential effects of a multivalent GAS vaccine in New Zealand. During January 2005–December 2006, we conducted prospective population-based laboratory surveillance of Auckland residents admitted to all public hospitals with isolation of GAS from normally sterile sites. Using emm typing, we identified 225 persons with confirmed invasive GAS infection (median 53 years of age; range 0–97 years). Overall incidence was 8.1 cases per 100,00 persons per year (20.4/100,000/year for Maori and Pacific Islanders; 24.4/100,000/year for persons >65 years of age; 33/100,000/year for infants

Objectives An increase of severe infections caused by Streptococcus dysgalactiae subsp. equisimilis (SDSE) similar to infections caused by Streptococcus pyogenes has been reported over the last years. Little is known about infections with SDSE in Austria. Therefore, we investigated a collection of 113 SDSE invasive and non-invasive isolates from different infection sites and type of infections as well as patients’ characteristics. Methods The isolates were phenotypically identified and emm typed using the enlarged emm database from the Centers for Disease Control and Prevention. Additionally, 13 antimicrobial agents were tested using EUCAST guidelines and virulence genes were investigated. Results Severe SDSE infections were most common in elderly men with underlying diseases especially diabetes mellitus. With VitekMS identification of SDSE isolates was successful to the species level only. Emm typing revealed 24 different emm types, one new type and one new subtype. StG485, stG6, stC74a, stG643, and stG480 were the predominant types in this study, stC74a and stG652 in invasive infections and stG643, stC74a and stG485 in non-invasive infections. Resistance was observed to tetracycline (62%), macrolides (13%) with one M phenotype, and clindamycin (12%) presenting 6 constitutive MLS B phenotypes and 8 inducible MLS B phenotypes. Levofloxacin resistance was detected only in one isolate. All isolates tested for virulence genes were positive for scpA , ska , saga and slo. Superantigenic genes were negative except speG dys (positive 17/34; 50%). Conclusion This paper presents the first report of SDSE infections in Austria. Severe SDSE infections were found mainly in elderly men with underlying diseases. SDSE isolates demonstrated substantial emm type diversity without association with infections site or invasiveness. Analysis of virulence genes showed no significant difference between invasive and non-invasive infections. [ABSTRACT FROM AUTHOR]

Objectives To survey antibiotic resistance among Streptococcus pyogenes isolates collected from 2005 to 2012, to characterize those showing erythromycin resistance and to analyse the association of certain emm types with erythromycin resistance or susceptibility. Methods Resistance determinants or mutations conferring erythromycin, clindamycin, tetracycline and fluoroquinolone resistance were analysed. All erythromycin-resistant isolates and a sample of erythromycin-susceptible isolates were emm typed. Multilocus sequence typing was performed for representative emm types. Results Antimicrobial susceptibility was studied for 12 346 S. pyogenes isolates. Erythromycin, clindamycin and tetracycline resistance showed a decreasing trend. In 2012, 2.8% of isolates were erythromycin resistant versus 7.5% in 2005 and 11.7% in 2006. Although 21 clones were involved, 4 clones accounted for almost 90% of erythromycin-resistant isolates. The emm12/ST36 clone, carrying the mef(A) gene, was the predominant (41.1%) erythromycin-resistant clone, with an incidence peak in 2008, followed by a gradual decline. The M phenotype predominated each year except for 2005, when two of the main erythromycin-resistant clones (emm11/ST403 and emm28/ST52) harboured an erm(B) gene. Erythromycin resistance was significantly higher in adults than in children. Skin isolates showed the highest erythromycin resistance rate; among these, perianal isolates frequently belonged to the emm28/ST52 clone. The emm type was not a predictor of erythromycin resistance; however, most emm11 and emm12 were erythromycin-resistant isolates. Macrolide consumption was similar throughout the study period. Only two isolates with a high level of levofloxacin resistance were detected. Conclusions Resistance was mainly related to the circulation of emm12/ST36, emm11/ST403, emm28/ST52 and emm4/ST39 clones, all of which declined throughout the study period. [ABSTRACT FROM PUBLISHER]

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. [ABSTRACT FROM AUTHOR]

Introduction: Beta-hemolytic streptococci (βHS) cause a diverse array of human infections. Despite the high number of cases of streptococcal carriers and diseases, studies discerning the molecular epidemiology of βHS in India are limited. This study reports the molecular and clinical epidemiology of beta-hemolytic streptococcal infections from two geographically distinct regions of India. Methodology: A total of 186 isolates of βHS from north and south India were included. The isolates were identified to species level and subjected to antimicrobial susceptibility testing. Polymerase chain reaction (PCR) was done to detect exotoxin genes, and emm types of group A streptococci (GAS) strains were ascertained by sequencing. Results: GAS was the most common isolate (71.5%), followed by group G streptococci (GGS) (21%). A large proportion of GAS produced speB (97%), smeZ (89%), speF (91%), and speG (84%). SmeZ was produced by 21% and 50% of GGS and GGS, respectively. A total of 45 different emm types/subtypes were seen in GAS, with emm 11 being the most common. Resistance to tetracycline (73%) and erythromycin (34.5%) was commonly seen in GAS. Conclusions: A high diversity of emm types was seen in Indian GAS isolates with high macrolide and tetracycline resistance. SpeA was less commonly seen in Indian GAS isolates. There was no association between disease severity and exotoxin gene production. [ABSTRACT FROM AUTHOR]

Background & objectives: Group A streptococcal (GAS) pharyngitis, especially among children, leads to high prevalence of rheumatic fever (RF)/rheumatic heart disease (RHD) in India, as compared to the western world where invasive diseases are common. GAS encodes numerous virulence factors that cause diseases by exhibiting extraordinary biological diversity. Hence, we studied the virulence factors genes of GAS isolated from the throat of children with pharyngitis and also asymptomatic carriers. Methods: Fifty GAS isolates cultured from throats of north Indian children aged 5-15 yr with mild pharyngitis (20), severe pharyngitis (24) and asymptomatic pharyngeal carriers (6), during 2000-2003 along with reference M1 strain were emm typed and characterized for virulence factors genes by PCR. The presence of virulence factors was also checked for their association with emm type in pharyngitis. Results: Twenty emm types, six sequence types, and one non-typeable strain were found circulating in north India. The five most prevalent types were emm 74 (12%), 11 & StI129 (8% each) and emm 68 and NS292 (6% each). The spe B gene was found to be significantly higher (P=-0.0007) in opacity factor (OF) negative isolates, emm 3, 11, 77, 86, 87, 109 and StI129 showed maximum virulence factors genes. Interpretation & conclusions: GAS isolates collected from throats of children frown north India possess highly virulent antigens. This study also supports concept of isolate-associated virulence rather than type relatedness. [ABSTRACT FROM AUTHOR]

Background & objectives: Group A streptococcus (GAS) causes a wide array of human diseases. Epidemiological picture of streptococcal infection in India is not complete. Hence, disease burden due to GAS in 5-15 yr old school children in northern India was studied and emm typing of GAS isolates was carried out to help in designing prevention strategies. Methods: A cross-sectional survey was carried out among 4249 school children (5-15 yr) from Raipur Rani Block of Panchkula district in Haryana during 2000-2002; 334 children were followed up fortnightly for one year. Standard clinical and microbiological procedures were used for collection of swabs from throat and skin and confirmation of GAS and its emm types. Results: Of the 4249 children studied, 658 (15.5%) had pharyngitis; 579 of them could be swabbed, of which 2.8 per cent had GAS. From 3591 children without pharyngitis, 3385 who could be swabbed, GAS was found in 1.3 per cent of them. Impetigo was rare (0.7%), but 7.1 per cent (2/28) children had GAS. In the followup study, 17.4 per cent (776/4447 child-contacts) had pharyngitis, 761 could be swabbed and 2.4 per cent had GAS; among those without pharyngitis, 2016 swabs could be taken and GAS was found in 1.3 per cent; whereas only 2.6 per cent (2/75) of skin sores had GAS. Three children had GAS pharyngitis twice during follow up. Fourteen different GAS emm types were found, emm 71, 77 and 81 constituted 69 per cent of the pharyngeal isolates. GAS pharyngitis and impetigo were more common in winters and summers respectively. Interpretation & conclusions: In north India, pharyngitis was more common than impetigo. Most prevalent emm types of GAS in this region differ from those included in M protein-based vaccines. [ABSTRACT FROM AUTHOR]

Watchful epidemiological surveillance of macrolide-resistant Group A Streptococcus (MRGAS) clones is important owing to the evolutionary and epidemiological dynamic of GAS. Meanwhile, data on the global distribution of MRGAS emm types according to macrolide resistance phenotypes and genotypes are scant and need to be updated. For this, the present systematic review analyses a global set of extensively characterized MRGAS isolates from patients of diverse ages and clinical presentations over approximately two decades (2000 to 2020) and recaps the peculiar epidemiological features of the dominant MRGAS clones. Based on the inclusion and exclusion criteria, 53 articles (3593 macrolide-resistant and 15,951 susceptible isolates) distributed over 23 countries were dissected with a predominance of high-income countries over low-income ones. Although macrolide resistance in GAS is highly variable in different countries, its within-GAS distribution seems not to be random. emm pattern E, 13 major emm types (emm12, 4, 28, 77, 75, 11, 22, 92, 58, 60, 94, 63, 114) and 4 emm clusters (A-C4, E1, E6, and E2) were significantly associated with macrolide resistance. emm patterns A-C and D, 14 major emm types (emm89, 3, 6, 2, 44, 82, 87, 118, 5, 49, 81, 59, 227, 78) and 3 well-defined emm clusters (A-C5, E3, and D4) were significantly associated with macrolide susceptibility. Scrutinizing the tendency of each MRGAS emm type to be significantly associated with specific macrolide resistance phenotype or genotype, interesting vignettes are also unveiled. The 30-valent vaccine covers ~95% of MRGAS isolates. The presented data urge the importance of comprehensive nationwide sustained surveillance of MRGAS circulating clones particularly in Low and Middle income countries where sampling bias is high and GAS epidemiology is obfuscated and needs to be demystified. • Macrolide resistant Group A Streptococcus (MRGAS) have emerged worldwide. • This review analyses a global set of extensively characterized MRGAS isolates. • A small subset of emm types was involved in the burden of macrolide resistance. • emm types were associated with specific macrolide resistance phenotype and genotype. • The 30-valent vaccine covers ~95% of worldwide MRGAS isolates. [ABSTRACT FROM AUTHOR]

The article offers information on Streptococcal Rheumatogenic Concept. Topics include exclusive group of strains harboring specific virulence factors capable of eliciting a host response that results in autoimmune reactions targeting host tissue; and inflammation of the mitral and aortic valves can lead to chronic damage.

Group A streptococcus (GAS) is a human pathogen causing a broad range of infections, linked with global morbidity and mortality. Macrolide resistance rates vary significantly in different parts of the world. Driving factors of the emergence and spread of resistant clones are not clearly understood. We investigated 102 macrolide-resistant GAS strains collected during the period 2014-2018 from various clinical specimens from Bulgarian patients. Strains were characterized by the presence of mefA/mefE, ermA, and ermB using polymerase chain reaction and sequencing for mefA/mefE. Resistant strains were studied by emm sequence typing and emm-cluster system. Most prevalent emm types among the macrolide-resistant GAS strains were emm28 (22.55%), emm12 (17.65%), and emm4 (16.66%). Almost all (87.25%) of the macrolide-resistant isolates harboring ermB were emm28. The isolates that carried ermA were predominantly emm12 (38.24%) and emm77 (38.24%), with fewer emm89 (23.53%). The isolates harbored predominantly mefE (49 isolates) and only 9 strains carried mefA. The most prevalent emm clusters among the GAS isolates were E4 (40.20%), A-C4 (17.65%), and E1 (16.66%). The study's results suggest that dissemination of specific clones in GAS population may also be the reason for the increasing macrolide-resistance rate in our country.