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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.
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@#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.
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@#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.
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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.
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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.
Sujets)
Adolescent , Enfant , Enfant d'âge préscolaire , Femelle , Humains , Nourrisson , Nouveau-né , Mâle , Infections à streptocoques/épidémiologie , Hôpitaux pédiatriques/statistiques et données numériques , Études rétrospectives , Facteurs de risque , Streptococcus pyogenes , Uruguay/épidémiologieRésumé
Objective:To analyze emm type,macrolide-resistance genes and superantigen gene profile of GAS isolates from children with pharyngitis in Chongqing.Methods:A total of 44 clinical isolates of GAS were obtained from children with pharyngeal diseases in 2007,Chongqing.The macrolide-resistant genotype(ermB,ermTR and mefA) and superantigen gene of group A streptococcal isolates(ssa、SMEZ、speA、speC、speG、speH、speI and speJ)were detected by PCR.Emm types were applied by PCR and sequencing.Results:Emm12 was the most common emm type(26 isolates,59.1%).Emm1 was the second(7 isolates,15.9%).Emm22 had 2 isolates,emm6 had 2 isolates,emm3 had 2 isolates,and emm80,emm63,emm102,stG485 and st1815 had 1 isolate respectively.All 44 isolates were detected ermB gene(100%),33 isolates were detected erm TR gene(75.0%),and 3 isolates were detected mefA gene(6.8%).All of the isolates were detected ssa,SMEZ and speH.The detection rates of other superantigen genes were speG(84.1%),spec(81.2%),speI(63.6%),speA(50%)and speJ(15.9%).Six in 7 isolates of emm1 type were detected speA gene(85.7%),and 7 in 26 isolates of emm12 type were detected speA gene(26.9%).The distribution of speA in emm1 and emm12 had a statistically significant difference(P=0.008,