Enfermedades invasoras por Streptococcus pyogenes en población pediátrica. Caracterización clínico-molecular 2014-2020 / Invasive diseases due to Streptococcus pyogenes in the pediatric population. Clinical-molecular characterization 2014-2020

INTRODUCCIÓN: Streptococcuspyogenes (EGA) es agente de enfermedad invasora (EI); su alta morbimortalidad exige vigilancia epidemiológica. OBJETIVO: Describir características clínicas y epidemiológicas de niños hospitalizados con EI por EGA en un centro de referencia de Uruguay del 1/1/2014 al 31/12/2020 incluyendo el estudio de los factores de virulencia encontrados en las cepas aisladas. MATERIALES Y MÉTODOS: Descriptivo y retrospectivo. Definición de caso: aislamiento de EGA. en sitios estériles. Variables: epidemiológicas, clínicas, laboratorio, tratamiento y evolución. Se tipificó por secuenciación del gen emm. Se obtuvieron perfiles cromosómicos por digestión del ADN con la enzima SmaI. Presencia de los genes que codifican SpeB, SpeA, SpeC y Ssa, y susceptibilidad a antimicrobianos. RESULTADOS: Tasa de admisiones: 3,98/10.000. Se incluyeron 22 pacientes; infección osteoarticular (n = 11), infección pleuropulmonar (n = 6), absceso no cutáneo (n = 4) y aislamiento en sangre (n = 1). Media de edad: 44 meses; 8 fueron graves, siendo su media de edad menor (16 meses) Todas los casos con neumonías fueron graves y un paciente falleció. Se secuenciaron 12 cepas: 5 emm1 (4 emm 1.29 y 1 emm 1) y 1 de cada uno de los siguientes: emm 6.4, emm 81, emm12, emm28, emm 22, emm 87, emm 11. Todas eran SpeB+. Perfiles de toxinas: SpeA+SpeC-Ssa-(5), SpeA-SpeC+Ssa-(4) SpeA-SpeC-Ssa-(2) y SpeA-SpeC+Ssa+ (2). CONCLUSIONES: Este estudio permite dar continuidad a un estudio previo. Se logró mayor tipificación de EGA. que puede contribuir a su conocimiento clínico molecular. No hubo registro de pacientes con diagnóstico de SST ni de fascitis necrosante, a diferencia de la serie anterior.

BACKGROUND: Streptococcus pyogenes (GAS) is an agent of invasive disease (ID); its high morbidity and mortality requires epidemiological surveillance. AIM: To describe the clinical and epidemiological characteristics of children hospitalized with ID due to GAS in a reference center in Uruguay from January 1-2014 to December 31-2020, including a study of virulence factors. METHODS: Descriptive and retrospective. Case definition: Isolation of GAS in sterile sites. Variables: epidemiological, clinical, laboratory, treatment and evolution. Strains were typified by sequencing of the emm gene. Chromosomal profiles were obtained by digestion of the DNA. with the Smal enzyme. Presence of SpeB, SpeA and SpeC genes and susceptibility to antibiotics were performed. RESULTS: Admissions rate: 3.98/10,000. 22 patients were included; osteoarticular infection (n = 11), pleuropulmonary infection (n = 6), non-cutaneous abscess (n = 4) and blood isolation (n = 1). Mean age: 44 months; 8 cases were severe, their mean age was lower (16 months). All pneumonia cases were severe and one patient died. Twelve strains were sequenced: 5 emm1 (4 emm1.29 and 1 emm1) and 1 of each: emm6.4, emm81, emm 12, emm28, emm 22, emm 87, emm 11. All were SpeB+. Toxin profiles: SpeA+SpeC-Ssa-(5), SpeA-SpeC+Ssa-(4) SpeA-SpeC-Ssa-(2) and SpeA-SpeC+Ssa+(2). CONCLUSIONS: This study allows to give continuity to a previous study. Greater typing of GAS was achieved, which may contribute to its molecular clinical knowledge. There was no record of patients diagnosed with TSS or necrotizing fascitis, unlike the previous series.

Multilocus sequence typing of Streptococcus pyogenes isolated from children in Shenzhen / 中华实用儿科临床杂志

Objective:To explore the epidemiological characteristics of Streptococcus pyogenes, namely β-hemolytic Group A Streptococcus (GAS) in children in Shenzhen. Methods:Multilocus sequence typing (MLST) data on the epidemic clonal population of GAS infection in children in Shenzhen Children′s Hospital from January 2016 to December 2018 were retrospectively analyzed.In the present study, 32 GAS strains belonging to 7 different emm types were from 32 children′s with impetigo, cellulitis, scarlet fever, sepsis, pneumonia, obstructive sleep apnea hypopnea syndrome, bronchitis, allergy with rhinitis, buttock abscess, allergic purpura or pharyngeal tonsillitis, which were isolated from 23 throat swabs, 5 sputum samples, 3 pus and 1 blood.Using polymerase chain reaction technology, 7 pairs of allelic housekeeping genes ( gki, gtr, murI, mutS, recP, xpt and yqiL) of 32 GAS isolates were analyzed, and the target gene products were subjected to sequencing.Then the obtained gene sequences of each allele were submitted to the MLST database to obtain the allele profile.Finally, the allele profiles were introduced in the MLST database again to confirm the sequence typing (ST). Results:The GAS clone groups of emm 1.00 and its subtypes, emm 4.00, emm 12.00 and its subtypes, emm 22.00, emm 28.00, emm 75.00, and emm 89.00 belonged to the sequence typing ST28, ST39, ST36, ST46, ST52, ST49, and ST921, respectively. Conclusions:From 2016 to 2018, the MLST clone populations of GAS isolates causing infections in children in Shenzhen are classified as ST28, ST39, ST36, ST46, ST52, ST49 and ST921.

Application of the emm cluster typing system in related studies of Group A Streptococcus / 中华实用儿科临床杂志

Group A Streptococcus (GAS) is one of the most important pathogens leading to children deaths all over the world.Bacterial typing is the commonest approach to analyzing the epidemiological characteristics of pathogenic microorganisms.The emm typing is frequently adopted to study GAS.The emm cluster typing is a recently proposed typing method based on the amino acid sequence homology of M proteins and the ability to bind to the host serum protein.This typing system has been extensively used for epidemiological investigation, strain selection and vaccine deve-lopment in foreign countries.However, it has not been applied in China yet. emm typing is based on a small variable region of emm genes, while the emm cluster typing system defines GAS types according to nearly intact sequences of emm genes.Besides, the emm cluster grouping system is acquired directly by emm typing comparison, so it is simple and feasible.Furthermore, the emm cluster typing can provide more information regarding the functional and structural properties of M proteins in different emm types of GAS.In this review, the methods, principles and applications of the emm cluster typing system in GAS research were summarized, in order to promote its application in China.

Analysis of emm typing and genomic polymorphism of Group A Streptococcus from children with scarlet fever in Shenzhen 2016-2018 / 中华实用儿科临床杂志

Objective:To identify the epidemic types of Group A Streptococcus (GAS)causing scarlet fever, to compare the gene structure and variability of GAS with different emm types, and to elucidate the epidemiological pattern of scarlet fever pathogens in Shenzhen. Methods:Pharyngeal swab samples were collected and analyzed retrospectively from children diagnosed with scarlet fever in Shenzhen Children′s Hospital from January 1, 2016 to May 31, 2018.The GAS strains were preserved for emm genotyping analysis.The strains of representative emm types were selected for whole-genome sequencing.The genomic polymorphism of GAS strains was described by comparative genomic analysis.Moreover, a phylogenetic tree was constructed based on the whole genome core-gene single nucleotide polymorphisms(SNPs) to clarify the evolutionary relationship between strains.Data between groups were compared by Rank sum test. Results:Among 176 GAS isolates that caused scarlet fever in children, 8 emm types were detected.The most common genotype was emm12.0 and its subtype(108/176 strains, 61.4%), followed by emm1.0 and its subtype(53/176 strains, 30.1%). These two genotypes accounted for 91.5% of all isolates collected.Comparative genome analysis was made taking GCA-900984775 as a reference sequence, and the results showed that the genomes of GAS strains had high levels of SNP and insertion or deletion (InDel) polymorphisms.There were more SNPs in emm12.0 strains[183(163, 213)] than those in emm1.0 strains[63 (54, 75)], and the difference was statistically significant ( P<0.05). As for InDel, more insertions and deletions [4(3, 6), 8(6, 10)] were observed in emm12.0 strains than those [1(0, 2), 5(3, 7)] in emm1.0 strains.According to the phylogenetic tree built by taking MGAS5005 as the reference sequence based on the whole genome core-gene SNPs, 18 strains and reference strains formed two clades. Conclusions:The emm12.0 and emm1.0 types are the most common GAS strains leading to scarlet fever in children.There are differences in the genome composition of different GAS strains.The emm12.0 strains have higher genetic diversity.

Distribution characteristics of emm genotype and superantigen of Group A Streptococcus isolated from the pharynx of children with scarlet fever-like erythema in Beijing / 中华实用儿科临床杂志

Objective:To analyze the genetic characteristics of Group A Streptococcus (GAS) isolated from the pharynx of children with scarlet fever-like erythema. Methods:Pharyngeal GAS isolates were collected retrospectively from children with scarlet fever-like erythema admitted in the Department of Dermatology, Beijing Children′s Hospital, Capital Medical University from June 2019 to February 2020.PCR and sequencing were used to detect emm genotyping and superantigen genes( speA, speB, speC, speF, speG, speH, speI, speJ, speK, speL, speM, ssa and smeZ) of the isolates.Data were compared by the chi-square test or Fisher′ s exact test between groups. Results:A total of 147 GAS strains were collected.The main emm genotypes were emm1.0 in 76 strains (51.70%) and emm12.0 in 60 strains (40.82%). Other 7 emm genotypes were all found in less than 5 strains.The detection rate of speF, smeZ, speG, speC, speB and ssa were as high as 100.00%(147/147 strains), 100.00%(147/147 strains), 99.32%(146/147 strains), 95.24%(140/147 strains), 94.56%(139/147 strains) and 92.52%(136/147 strains), respectively. speA, speJ, speI, speH and speM had a low detection rate of 51.70%(76/147 strains), 49.66%(73/147 strains), 32.65%(48/147 strains), 23.81%(35/147 strains) and 4.08%(6/147 strains), respectively.No speK and speL were detected.The frequencies of speA and speJ in emm1.0 strains (65/76 strains, 85.53% and 64/76 strains, 84.21%) were significantly higher than those in emm12.0 strains (4/60 strains, 6.67% and 6/60 strains, 10.00%). However, the frequencies of speH and speI in emm1.0 strains (7/76 strains, 9.21% and 2/76 strains, 2.63%) were significantly lower than those in emm12.0 strains (28/60 strains, 46.67% and 45/60 strains, 75.00%) (all P<0.001). Conclusions:At present, emm1.0 and emm12.0 are the main GAS strains isolated from the throat of children with scarlet fever-like erythema in Beijing, and emm1.0 is more common.There is a correlation between emm genotyping and the superantigen gene profile.Type 1 superantigen gene profile is significantly more frequently detected in emm1.0 strains than in emm12.0 strains.Type 2, 3 and 4 superantigen gene profiles are significantly more frequently detected in emm12.0 strains than in emm1.0 strains.

Analysis of emm genotypes and drug susceptibility characteristic variations of Group A Streptococcus in children in Beijing / 中华实用儿科临床杂志

Objective:To clarify the M protein ( emm gene) types and drug susceptibility characteristic variations of Group A Streptococcus (GAS) in children in Beijing. Methods:The GAS strains isolated from throat swab samples of children diagnosed with scarlet fever and pharyngeal infection in scarlet fever etiology surveillance sentinel hospitals in 16 districts of Beijing in 2018, 2019 and 2021 were analyzed retrospectively.PCR amplification and sequencing were used for emm genotyping, and the minimum inhibitory concentrations (MIC) of 10 antibiotics were determined by the broth microdilution method.The data were analyzed using χ2 test and Fisher′ s exact method between groups. Results:A total of 557 GAS strains were collected, and 11 emm genotypes ( emm1, emm3, emm4, emm6, emm11, emm12, emm22, emm75, emm89, emm128, and emm212) were detected.Of 557 strains, 238 trains were of emm1 type (42.73%), 271 strains were of emm12 type (48.65%) and 48 strains were of other emm types (8.62%). The detection rates of emm1, emm12 and other emm type genes in 2018, 2019, and 2021 were [37.50% (105/280 strains), 57.14% (160/280 strains), 5.36% (15/280 strains)], [49.05% (129/263 strains), 39.54% (104/263 strains), 11.41% (30/263 strains)], and [28.57% (4/14 strains), 50.00% (7/14 strains), 21.43% (3/14 strains)], respectively.In children infected with emm12 in 2018 and 2019, there were more children under 6 years old than children over 6 years old (62.50% vs.46.88%, 46.36% vs.30.36%) (χ 2=7.182, 6.973; all P<0.05). Drug susceptibility testing results suggested that 225 randomly selected GAS strains were all 100.00% sensitive to 7 antibiotics including Penicillin, Levofloxacin, Meropenem, Linezolid, Cefotaxime, Cefepime and Vancomycin.The rates of resistance to Erythromycin, Tetracycline and Clindamycin were [88.57% (93/105 strains), 87.62% (92/105 strains), 86.67% (91/105 strains)], and [94.34% (100/106 strains), 94.34% (100/106 strains), 87.74% (93/106 strains)] in 2018 and 2019, respectively.The test strains were 100.00% (14/14 strains) resistant to the above 3 antibiotics in 2021.MIC 50 and MIC 90 values of Penicillin in 2018, 2019, and 2021 were (0.03 mg/L, 0.03 mg/L), (0.03 mg/L, 0.06 mg/L), and (0.06 mg/L, 0.06 mg/L), respectively.Among 225 GAS strains, 207 strains had drug resistance and were resistant to more than one drug.Specifically, 94.69% (196/207 strains) were resistant to Erythromycin, Tetracycline and Clindamycin.About 4.35% (9/207 strains) were resistant to both Erythromycin and Clindamycin.A total of 0.97% (2/207 strains) were resistant to Erythromycin and Tetracycline. Conclusions:The emm genotypes of GAS in children in Beijing are diverse in 2018, 2019 and 2021.The dominant genotypes are emm12 and emm1, and emm12 is the main epidemiological type.GAS strains maintain highly resistant to Erythromycin, Clindamycin and Tetracycline, and sensitive to Penicillin and other antibiotics.However, MIC 50 and MIC 90 of Penicillin shows an ascending trend.

In Vitro Assessment of Biofilm Formation by Streptococcus pyogenes Isolates From Invasive and Non-invasive Samples With Diverse emm Type Profiles

@#Introduction: Biofilm is one of the important virulence factors that is responsible for the severity and progression of the Streptococcus pyogenes diseases. M-protein is involved in the irreversible attachment of S. pyogenes to surfaces during biofilm development. This study aims to determine the propensity of S. pyogenes to form biofilms and the molecular epidemiology of S. pyogenes isolates by emm typing. Methods: We screened 45 S. pyogenes isolates for the biofilm formation by Congo red agar (CRA) and quantified the biofilms by crystal violet microtiter-plate methods (CVMtP). The emm typing of all isolates was performed by conventional PCR with established primers according to the CDC protocol. Results: Majorities of S. pyogenes were isolated from non-invasive, 27 (60.0%) than invasive sources, 18 (40.0%). Regardless of invasiveness, 40 (88.9%) S. pyogenes isolates formed black colonies on CRA, while 43 (95.6%) of the isolates demonstrated various degrees of biofilm formation by CVMtP method. A total of 30 different emm types and subtypes were identified. No new emm types/subtypes were detected. The predominant emm types/subtypes were emm1, emm63, emm18.21, emm91, and emm97.4 which each gene accounted for 7.0%. All emm types/subtypes of S. pyogenes produced biofilms by CVMtP method except emm17.2 and emm57 which were isolated from non-invasive sources. Conclusions: Biofilm-producing S. pyogenes strains of various sources are genetically diverse and biofilm phenotypes are inherent to individual characteristic rather than specific emm type. Nonetheless, higher propensity of GAS to form biofilms warrants better management strategies to avoid treatment failures in the future.

Distribution of virulence genes and the molecular epidemiology of Streptococcus pyogenes clinical isolates by emm and multilocus sequence typing methods

@#Background: Streptococcus pyogenes has a variety of virulence factors and the predominant invasive strains differ according to specific emm types and geographical orientation. Although emm typing is commonly used as the gold standard method for the molecular characterisation, multilocus sequence typing (MLST) has become an important tool for comparing the genetic profiles globally. This study aimed to screen selected virulence genes from invasive and non-invasive clinical samples and to characterise the molecular epidemiology by emm typing and MLST methods. Materials and Methods: A total of 42 S. pyogenes isolates from invasive and non-invasive samples collected from two different tertiary hospitals were investigated for the distribution of virulence factors and their molecular epidemiology by emm and multilocus sequence typing methods. Detection of five virulence genes (speA, speB, speJ, ssa and sdaB) was performed using multiplex polymerase chain reaction (PCR) using the standard primers and established protocol. Phylogenetic tree branches were constructed from sequence analysis utilised by neighbour joining method generated from seven housekeeping genes using MEGA X software. Results: Multiplex PCR analysis revealed that sdaB/speF (78.6%) and speB (61.9%) were the predominant virulence genes. Regardless of the type of invasiveness, diverse distribution of emm types/subtypes was noted which comprised of 27 different emm types/subtypes. The predominant emm types/subtypes were emm63 and emm18 with each gene accounted for 11.8% whereas 12% for each gene was noted for emm28, emm97.4 and emm91. The MLST revealed that the main sequence type (ST) in invasive samples was ST402 (17.7%) while ST473 and ST318 (12% for each ST) were the major types in non-invasive samples. Out of 18 virulotypes, Virulotype A (five genes, 55.6%) and Virulotype B (two genes, 27.8%) were the major virulotypes found in this study. Phylogenetic analysis indicated the presence of seven different clusters of S. pyogenes. Interestingly, Cluster VI showed that selected emm/ST types such as emm71/ST318 (n=2), emm70.1/ST318 (n=1), emm44/ST31 (n=1) and emm18/ST442 (n=1) have clustered within a common group (Virulotype A) for both hospitals studied. Conclusion: The present study showed that group A streptococcci (GAS) are genetically diverse and possess virulence genes regardless of their invasiveness. Majority of the GAS exhibited no restricted pattern of virulotypes except for a few distinct clusters. Therefore, it can be concluded that virulotyping is partially useful for characterising a heterogeneous population of GAS in hospitals.

Molecular epidemiological characteristics of Streptococcus pyogenes causing scarlet fever and angina in children / 中华微生物学和免疫学杂志

Objective@#To investigate the antimicrobial resistance, macrolide-resistance genes, virulence genes and emm types in Streptococcus pyogenes isolates.@*Methods@#A total of 247 oropharyngeal swab specimens were collected from pediatric outpatients (aged 2-11 years) who were clinically diagnosed as scarlet fever in Children′s Hospital of Fudan University from January to December, 2018. These specimens were timely sent to the Microbiology Laboratory for isolation and identification of Streptococcus pyogenes strains were isolate after culturing and identified with bacitracin susceptibility test. Moreover, the diameter of bacitracin inhibition zone was measured by vernier caliper. Their susceptibility to seven antibiotics, including erythromycin, clarithromycin, clindamycin, ampicillin, ceftriaxone, norfloxacin and chloramphenicol, were measured using KB method. Macrolide-resistance genes (mefA, ermA, ermB and Tn916 transposon) and virulence genes (speA, speB, speC, speG, speH, speI, speJ and speK) were detected by PCR. Amplification and sequencing of emm gene were conducted according to the protocol in the website of Centre for Disease Control and Prevention (CDC).@*Results@#A total of 86 strains of Streptococcus pyogenes were isolated from the 247 specimens. Their resistance rates to erythromycin, clarithromycin and clindamycin were 89.5%, 95.3% and 96.5%, respectively. However, these isolates showed high susceptibility to ampicillin (100.0%), ceftriaxone (100.0%), norfloxacin (90.7%) and chloramphenicol (95.3%). The positive rates of mefA, ermA, ermB and Tn916 genes were 20.9%, 24.4%, 98.8% and 97.7%. There was significant difference in the mefA-carrying rates between patients with scarlet fever and angina. The positive rates of virulence genes of speA, speB, speC, speG, speH, speI, speJ, speK, speL and speM were 8.1%, 100.0%, 95.3%, 100.0%, 80.2%, 90.7%, 10.5%, 100.0%, 5.8% and 5.8%. Seven emm types were identified and the predominant types were emm12.0 (75.6%), emm12.19 (9.3%) and emm1.0 (8.1%). The diameter of bacitracin inhibition zone was smaller in isolates of emm1.0 type than in emm12.0 type strains. The profile of virulence genes varied in the strains of different emm types. All types of strains carried speB, speG and speK genes. The isolates of emm1.0 type carried speA virulence gene, while speB, speC, speG, speH, speI and speK genes were more often identified in emm12.0 type isolates.@*Conclusions@#This study showed that emm types were associated with the profile of virulence genes and the diameter of bacitracin inhibition zone. It was recommended that the diameter of bacitracin inhibition zone should be measured in bacitracin inhibition susceptibility test apart from only observing the formation of inhibition zone.

Incidence of Scarlet Fever in Children in Jeju Province, Korea, 2002-2016: An Age-period-cohort Analysis / 예방의학회지

OBJECTIVES: Outbreaks of scarlet fever in Mexico in 1999, Hong Kong and mainland China in 2011, and England in 2014-2016 have received global attention, and the number of notified cases in Korean children, including in Jeju Province, has also increased since 2010. To identify relevant hypotheses regarding this emerging outbreak, an age-period-cohort (APC) analysis of scarlet fever incidence was conducted among children in Jeju Province, Korea. METHODS: This study analyzed data from the nationwide insurance claims database administered by the Korean National Health Insurance Service. The inclusion criteria were children aged ≤14 years residing in Jeju Province, Korea who received any form of healthcare for scarlet fever from 2002 to 2016. The age and year variables were categorized into 5 groups, respectively. After calculating the crude incidence rate (CIR) for age and calendar year groups, the intrinsic estimator (IE) method was applied to conduct the APC analysis. RESULTS: In total, 2345 cases were identified from 2002 to 2016. Scarlet fever was most common in the 0-2 age group, and boys presented more cases than girls. Since the CIR decreased with age between 2002 and 2016, the age and period effect decreased in all observed years. The IE coefficients suggesting a cohort effect shifted from negative to positive in 2009. CONCLUSIONS: The results suggest that the recent outbreak of scarlet fever among children in Jeju Province might be explained through the cohort effect. As children born after 2009 showed a higher risk of scarlet fever, further descriptive epidemiological studies are needed.

Molecular Epidemiological Features and Antibiotic Susceptibility Patterns of Streptococcus dysgalactiae subsp. equisimilis Isolates from Korea and Japan

BACKGROUND: The molecular characterization of Streptococcus dysgalactiae subsp. equisimilis (SDSE) has not yet been performed in Korea. This study aimed to find the differences or similarities in the clinical features, molecular epidemiological findings, and antimicrobial resistance patterns of SDSE from two countries (Korea and Japan). METHODS: SDSE isolates were collected from Korea (N=69) from 2012–2016 and Japan (N=71) from 2014–2016. Clinical characteristics, emm genotypes, and sequence types (STs) were compared. Microdilution tests were performed using different antimicrobials, and their resistance determinants were screened. RESULTS: Median ages were 69 years in Korea and 76 years in Japan. The most common underlying diseases were diabetes and malignancy. Blood-derived isolates comprised 36.2% and 50.7% of Korean and Japanese isolates, respectively; mortality was not different between the two groups (5.8% vs 9.9%, P=0.53). Among Korean isolates with 20 different combined ST-emm types, ST127-stG245 (N=16), ST128-stG485 (N=10), and ST138-stG652 (N=8) were prevalent. Among Japanese isolates with 29 different combined types, ST17-stG6792 (N=11), ST29-stG485 (N=7), and ST205-stG6792 (N=6) were prevalent. Resistance rates to erythromycin, clindamycin, and minocycline were 34.8%, 17.4%, and 30.4% in Korea and 28.2%, 14.1%, and 21.4% in Japan, respectively. CONCLUSIONS: SDSE infections commonly occurred in elderly persons with underlying diseases. There was a significant difference in the distribution of ST-emm types between the two countries. Antimicrobial resistance rates were comparable with different frequencies of resistance determinants in each country.

Study on the super-antigen genes of group A Streptococcus pyogenes strains isolated from patients with scarlet fever and pharyngeal infection, in Beijing, 2015-2017 / 中华流行病学杂志

Objective To analyze the characteristics of super-antigen (SAg) of group A Streptococcus pyogenes (GAS),isolated from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017.Methods Throat swab specimens from patients with scarlet fever or pharyngeal infections were collected and tested for GAS.Eleven currently known SAg genes including SpeA,speC,speG,speH,speI,speJ,speK,speL,speM,smeZ and ssa were tested by real-time PCR while M protein genes (emm genes) were amplified and sequenced by PCR.Results A total of 377 GAS were isolated from 6 801 throat swab specimens,with the positive rate as 5.5％.There were obvious changes noticed among speC,speG,speH and speK in three years.A total of 45 SAg genes profiles were observed,according to the SAgs inclusion.There were significant differences appeared in the frequencies among two of the highest SAg genes profiles between emml and emml2 strains (x2=38.196,P＜0.001;x 2=72.310,P＜0.001).There also appeared significant differences in the frequencies of speA,speH,speI and speJ between emm 1 and emm 12 strains (x2 =146.154,P＜ 0.001;x2=52.31,P＜0.001;x2=58.43,P＜0.001;x2=144.70,P＜0.001).Conclusions Obvious changes were noticed among SAg genes including speC,speG,speH and speK from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017.SAg genes including speA,speH,speI and speJ appeared to be associated with the emm 1 and emm 12 strains.More kinds of SAg genes profiles were isolated form GAS but with no significant differences seen in the main SAg genes profiles,during the epidemic period.

Study on the super-antigen genes of group A Streptococcus pyogenes strains isolated from patients with scarlet fever and pharyngeal infection, in Beijing, 2015-2017 / 中华流行病学杂志

Objective To analyze the characteristics of super-antigen (SAg) of group A Streptococcus pyogenes (GAS),isolated from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017.Methods Throat swab specimens from patients with scarlet fever or pharyngeal infections were collected and tested for GAS.Eleven currently known SAg genes including SpeA,speC,speG,speH,speI,speJ,speK,speL,speM,smeZ and ssa were tested by real-time PCR while M protein genes (emm genes) were amplified and sequenced by PCR.Results A total of 377 GAS were isolated from 6 801 throat swab specimens,with the positive rate as 5.5％.There were obvious changes noticed among speC,speG,speH and speK in three years.A total of 45 SAg genes profiles were observed,according to the SAgs inclusion.There were significant differences appeared in the frequencies among two of the highest SAg genes profiles between emml and emml2 strains (x2=38.196,P＜0.001;x 2=72.310,P＜0.001).There also appeared significant differences in the frequencies of speA,speH,speI and speJ between emm 1 and emm 12 strains (x2 =146.154,P＜ 0.001;x2=52.31,P＜0.001;x2=58.43,P＜0.001;x2=144.70,P＜0.001).Conclusions Obvious changes were noticed among SAg genes including speC,speG,speH and speK from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017.SAg genes including speA,speH,speI and speJ appeared to be associated with the emm 1 and emm 12 strains.More kinds of SAg genes profiles were isolated form GAS but with no significant differences seen in the main SAg genes profiles,during the epidemic period.

The emm genotype of group A streptococcus isolated from clinical infected children,Beijing / 国际检验医学杂志

Objective To reveal the genetic distribution of group A streptococcus progeny(GAS)isolated from children with re-spiratory tract infection in Beijing in 2015.Methods The throat swabs were collected from children with clinical diagnosis of scarlet fever and pharyngeal infection during May to July,2015.16 pediatric outpatient departments or pediatric emergency department of hospitals located in 16 districts of Beijing were enrolled in this study.PCR amplification and gene sequencing were employed.The encoding mature M protein gene(emm)distribution in different condition was compared and analyzed.Results A total of 247 GAS were isolated,including 73(29.6%,73/247)isolates from cases with scarlet fever and 174(70.4%,174/247)isolates from cases with pharyngeal infection.Among all isolates,six genotypes of emm were identified,including emm12(53.4%,132/247),emm1(44. 1%,109/247)and others(emm22,emm75,emm131 and emm241,2.5%,6/247).The significant difference of emm distribution with age was observed in this study:emm1 isolates were dominant in children aged 6-12,whereas emm12 isolates were dominant in chil-dren aged 1-5(P<0.05).While the emm distribution showed no significant difference in groups with different location,gender,and disease pattern(P>0.05).Conclusion Emm1 and emm12 were the circulating genotype of GAS in Beijing children,2015.Moreo-ver,the difference of distribution between emm1 and emm12 was proved in this study.

Prevalence of Complement-Mediated Cell Lysis-like Gene (sicG) in Streptococcus dysgalactiae subsp. equisimilis Isolates From Japan (2014–2016)

BACKGROUND: Streptococcus dysgalactiae subsp. equisimilis (SDSE; a β-hemolytic streptococcus of human or animal origin) infections are emerging worldwide. We evaluated the clonal distribution of complement-mediated cell lysis-like gene (sicG) among SDSE isolates from three central prefectures of Japan. METHODS: Group G/C β-hemolytic streptococci were collected from three institutions from April 2014 to March 2016. Fifty-five strains (52 from humans and three from animals) were identified as SDSE on the basis of 16S rRNA sequencing data.; they were obtained from 25 sterile (blood, joint fluid, and cerebrospinal fluid) and 30 non-sterile (skin-, respiratory tract-, and genitourinary tract-origin) samples. emm genotyping, multilocus sequence typing, sicG amplification/sequencing, and random amplified polymorphic DNA (RAPD) analysis of sicG-positive strains were performed. RESULTS: sicG was detected in 30.9% of the isolates (16 human and one canine) and the genes from the 16 human samples (blood, 10; open pus, 3; sputum, 2; throat swab, 1) and one canine sample (open pus) showed the same sequence pattern. All sicG-harboring isolates belonged to clonal complex (CC) 17, and the most prevalent emm type was stG6792 (82.4%). There was a significant association between sicG presence and the development of skin/soft tissue infections. CC17 isolates with sicG could be divided into three subtypes by RAPD analysis. CONCLUSIONS: CC17 SDSE harboring sicG might have spread into three closely-related prefectures in central Japan during 2014–2016. Clonal analysis of isolates from other areas might be needed to monitor potentially virulent strains in humans and animals.

Molecular epidemiological analysis of Streptococcus pyogenes strains isolated from the adult and pediatric patients in Shanghai,China / 中国感染与化疗杂志

Objective To investigate and compare the molecular epidemiological characteristics of Streptococcus pyogenes isolates from Shanghai adult and pediatric patients in terms of antimicrobial susceptibility ,clone type ,emm type ,biofilm formation and virulence for better infection control and treatment .Methods Thirty‐nine nonduplicate clinical isolates of S . pyogenes from adult and pediatric patients were analyzed by determining the susceptibility to antimicrobial agents by Kirby‐Bauer method;clonal typing by multilocus sequence typing ( MLST ); genotyping by emm gene sequence analysis ,which encoding M protein;genomic characteristics of different emm type strains by pulsed field gel electrophoresis (PFGE );and biofilm formation by semi‐quantitative biofilm formation test . Twenty main virulence genes of S .pyogenes ,including 12 superantigen genes and 8 other key genes were detected by PCR and gel electrophoresis . Results A total of 39 nonduplicate S .pyogenes isolates were analyzed .The most common genotype was emm 12‐ST36 (64 .1% ) and emm 1‐ST28 (17 .9% ) .Isolates from adult and pediatric patients had the same dominant genotype , emm 12‐ST36 . The isolates from children showed significantly higher resistance rate to erythromycin and clindamycin than those from adult patients (P<0 .000 1) .Particular emm type and clone type were frequently identified in the same PFGE cluster .Statistical analysis showed that biofilm formation was significantly associated with emm type 1 (P=0 .005) and erythromycin/clindamycin resistance (P=0 .000 3) .The strains from children showed higher biofilm formation than those from adult patients (P<0 .000 1) .We found that virulence genes speA ,speJ and spd3 were significantly associated with emm type 1 (P<0 .000 1 ,P=0 .005 5 ,P<0 .000 1) ,while speI and sic were significantly associated with emm type 12 (both P<0 .000 1) .We also found that the prevalence of speC ,speH ,ssa , smeZ ,and sdaD genes was significantly different between emm type 12 and emm type 1 (P= 0 .023 8 , P< 0 .000 1 , P<0.0001,P= 0.0003,and P= 0.0068,respectively).TheprevalenceofvirulencegenesspeH,smeZandsdaDwas significantly different between the emm type 12 strains from children and those from adults (all P< 0 .000 1) .Conclusions There is a strong agreement between emm type ,clone type ,virulence genes and the clusters defined by PFGE profiling of S . pyogenes .S .pyogenes isolates from adult and pediatric patients are different in terms of antibiotic resistance and biofilm formation .Certain emm type is significantly associated with antibiotic resistance and virulence ,which is useful for infection control .Dominant virulence genes may be the potential target for developing new vaccine to reduce S .pyogenes infection in the future .

Study on the relationship between M protein gene-types and superantigen genes of Group A Streptococcus pyogenes strains isolated from scarlet fever patients in Beijing / 中华传染病杂志

Objective To explore the relationship between superantigen and M protein gene (emm)-types genes of Group A Streptococcus pyogenes (GAS) isolated from patients with scarlet fever in Beijing from May 2012 to July 2013 .Methods GAS was isolated from specimens of patients with scarlet fever . Superantigen genes (speA ,speB ,speC ,speF ,speG ,speH ,speI ,speJ ,speL ,speK ,speM ,ssa ,and smeZ) ,and emm gene were amplified by polymerase chain reaction .Rate and proportion were compared by chi-square test .Results Of the 423 GAS strains isolated from patients with scarlet fever from 2012 to 2013 ,most of the isolates possessed speB (97 .6% ) ,speC (99 .8% ) ,speF (98 .3% ) ,speG (99 .8% ) , smeZ (94 .1% ) and ssa (88 .4% ) ,and some of them possessed speH (54 .6% ) ,speI (53 .4% ) ,speA (45 .2% ) and speJ (43 .5% ) ,but very few isolates possessed speK (2 .4% ) ,speL (1 .4% ) and speM (1 .7% ) .Type emm12 (59 .5% ) and type emm1 (37 .4% ) were the main types of GAS .Most of the emm12-type isolates possessed speH (84 .8% ) and speI (84 .0% ) compared with only 4 .0% of speH and 3 .4% of speI in type emm1 .Most of type emm1 possessed speA (95 .3% ) and speJ gene (94 .6% ) compared with only 17 .3% of speA and 14 .8% of speJ in type emm12 .The superantigen genes profiles were significant different between emm 1-type and emm 12-type isolates (P< 0 .05) .Conclusion Type emm1 and type emm12 are epidemic strains in patients with scarlet fever from 2012 to 2013 in Beijing ,and emm gene-types are associated with superantigen genes profiles .

Enfermedades invasoras por Streptococcus pyogenes 2005-2013: Hospital Pediátrico del Centro Hospitalario Pereira Rossell, Uruguay / Invasive Streptococcus pyogenes diseases 2005-2013: Pediatric Hospital Pereira Rossell Uruguay

Introduction: Streptococcus pyogenes infection causes a wide spectrum of clinical manifestations. Invasive disease (ID) is defined by the isolation of the microorganism from sterile sites. Objective: To analyze the clinical, epidemiological and molecular characteristics of ID by S.pyogenes in children hospitalized at Pediatric Hospital Pereira Rossell, from January 2005 to January 2013. Materials and Methods: A descriptive retrospective study was done in cases with isolation of S.pyogenes from sterile sites. Epidemiological variables, disease characteristics, laboratory parameters, treatment regimen received, hospitalization days and clinical outcome were analyzed. The presence of 4 genes encoding for virulence factors and chromosome profile studied by pulsed-field electrophoresis were done in the isolated strains. Results: A total of 42 cases (rate: 4.6 out of 10,000 admissions) were detected, from which 32 were analyzed. Average age was 44.7 months (14/32 < 2 years of age). In 5 cases, the portal of entry was identified. Clinical presentations were: osteoarticular infections (n = 15), shock (n = 6), skin and soft-tissue infections (n = 5), pneumonia (n = 3) and bacteremias (n = 3). Twenty cases required surgical procedures and 13 required intensive care admission. Average hospital stay was 17 days and one patient died. Molecular studies were performed in five strains; 4 different toxin profiles and pulsotypes were identified. Discussion: The incidence of ID at our hospital is similar to other series in the region. A better knowledge of clinical presentation and its relation with molecular characteristics represents a challenge.

Introducción: Streptococcus pyogenes, produce diversas manifestaciones clínicas. La enfermedad invasora (EI) se define por el aislamiento del microorganismo en sitios estériles. Objetivo: Analizar características clínico-epidemiológicas y moleculares de EI por S. pyogenes en niños hospitalizados en el HP-CHPR (1/1/05-31/1/13). Materiales y Métodos: Estudio descriptivo, retrospectivo, de casos con aislamiento de S. pyogenes de sitios estériles. Se analizaron variables epidemiológicas, características de la enfermedad, laboratorio, tratamientos, días de hospitalización y evolución. Se estudió la presencia de cuatro genes que codifican factores de virulencia y perfiles cromosómicos resueltos por electroforesis en campos pulsados. Resultados: Se detectó un total de 42 casos (tasa 4,6 cada 10.000 admisiones), se analizaron todas las variables en 32. Mediana de edad 44,7 meses (14 < 2 años). En cinco se identificó puerta de entrada. Formas de presentación: infección osteo-articular (n: 15), shock (n: 6), infección de piel y tejidos blandos (n: 5), neumonía (n: 3) y bacteriemia (n: 3). Veinte requirieron procedimientos quirúrgicos y 13 de cuidado intensivo. La media de estadía hospitalaria fue de 17 días. Hubo un fallecimiento. Se realizó estudios moleculares en cinco cepas, identificándose cuatro perfiles de toxinas y pulsotipos diferentes. Discusión: La incidencia de EI en nuestra institución coincide con otras series en la región. Profundizar el conocimiento de la presentación clínica y su relación con las características moleculares es un desafío.

Group A Sstreptococcus virulence factors genes in north India & their association with emm type in pharyngitis.

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 from north India possess highly virulent antigens. This study also supports concept of isolate-associated virulence rather than type relatedness.

Multicenter Study of Molecular Epidemiology and Antibiotic Resistance of Group A Streptococci in 2008-2009 in Korea / 대한임상미생물학회지

BACKGROUND: Group A Streptococcus (GAS) is responsible for a wide spectrum of human diseases. We investigated the distribution of emm types and antibiotic resistance rates of GAS from clinical specimens in several Korean medical centers. METHODS: A total of 192 strains of GAS from throat, blood, and other specimens collected in Seoul, Busan, Ulsan, Iksan, and Jeju were studied in 2008-2009. The emm genotypes were identified using PCR and sequencing. Antimicrobial susceptibility testing was performed by disk diffusion method. Phenotypes of macrolide resistance were evaluated, and macrolide resistance genes were determined by PCR. RESULTS: The emm89 (33.9%) was most frequently detected, followed by emm1 (12.5%), emm12 (8.3%), emm4 (7.8%), and emm75 (7.3%). The distribution of emm types did not show a close relation to the type of specimen and was different for each area. The resistance rates to erythromycin (ERY) and clindamycin (CLI) were 4.6% and 3.7%, respectively. Among the nine ERY-resistant strains, the rate of constitutive resistance was 88.9%, compared with 11.1% for the M phenotype. Five of the ERY-resistant strains were emm28. CONCLUSION: This multicenter study reveals heterogenous emm genotypes by geographic area. Rates of resistance to ERY and CLI were low, and most of the ERY-resistant strains showed a constitutive macrolide-lincosamide-streptogramin B (cMLSB) phenotype.