1001 resultados para STREPTOCOCCUS PYOGENES


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Universidade Estadual de Campinas. Instituto de Biologia

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Streptococcus pyogenes can be efficiently internalized by a variety of human epithelial cells. β-lactam antibiotics, commonly used to treat S. pyogenes infections, do not readily permeate mammalian cells. There is growing evidence that the ability of streptococci to enter host cells contributes to the frequent failure of antibiotics to eradicate the organism from infected individuals. Recent studies have suggested that host cell entry requires the formation of a complex of a bacterial fibronectin (Fn) binding protein (e.g., M1 protein or protein F1/SfbI), human Fn, and the epithelial cell Fn receptor, integrin α5β1. We report here that a low molecular weight, nonpeptide antagonist of integrin α5β1, SJ755, can inhibit internalization of streptococci by primary human tonsillar epithelial cells and immortalized human epithelial (A549) cells, thus increasing the extent of bacterial killing by antibiotics. SJ755 blocked Fn binding by human tonsillar epithelial and A549 cells, suggesting that integrin α5β1 is the major Fn receptor expressed by both cell types. SJ755 did not affect Fn binding by purified M1 protein or M1+ bacteria. Purified M1 protein failed to associate with integrin α5β1 unless the integrin had been prebound by Fn. Also, SJ755 blocked formation of α5β1-Fn-M1 complexes in vitro. These results support the previous proposal that Fn functions as a molecular bridge between M1 protein and integrin α5β1. Furthermore, these results suggest that integrin antagonists may enhance the efficacy of antibiotics in treatment of S. pyogenes infections.

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O Streptococcus pyogenes é uma bactéria que pode colonizar o epitélio da mucosa da orofaringe e a camada epidérmica da pele, mas também a vagina, o ânus e o couro cabeludo, em menor proporção. Contudo, esta bactéria apresenta uma grande capacidade de adaptação a diversas condições fisiológicas, permitindo-lhe provocar um largo espectro de patologias divididas em: localização (amigdalite/faringite e infecções de feridas); invasivas (fasceíte necrosante, osteomielite e bacteriémia); mediadas por toxinas (escarlatina e a síndrome de choque tóxico estreptocócico); e pós-estreptocócicas (febre reumática e a glomerulonefrite pós-estreptocócica). Os principais objectivos deste trabalho são avaliar as características epidemiológicas do Streptococcus pyogenes num Hospital Distrital Português determinando a patologia mais frequente causada por esta bactéria de acordo com o diagnóstico clínico, o escalão etário mais afectado pela infecção e a variação sazonal deste agente etiológico durante o período de 1 de Janeiro de 2008 e 31 de Dezembro de 2009. Os dados utilizados para a realização deste estudo retrospectivo foram recolhidos de pacientes que deram entrada nos diversos serviços hospitalares de um Hospital Distrital com cultura positiva para Streptococcus pyogenes entre Janeiro de 2008 e Dezembro de 2009. O tratamento dos dados foi realizado em SPSS 17.0. Após a recolha de dados, foram obtidos um total de 476 amostras com cultura positiva para Streptococcus pyogenes, sendo a maioria exsudatos orofaríngeos (97,9%). Desta forma, optou-se por tratar a parte mais relevante da estatística, restringindo o estudo a esta fracção. A patologia mais frequente de acordo com o diagnóstico clínico foi a amigdalite. Contudo, 7,1% das culturas positivas não indicavam diagnóstico. Para determinar o escalão etário mais afectado pelas infecções de Streptococcus pyogenes no Hospital Distrital durante o período de estudo dividiu-se a população de estudo por 5 escalões, sendo o escalão pré-escolar o mais afectado. Quanto à variação sazonal de um ano para outro ressalta a variabilidade do número de infecções, bem como, a discrepância da percentagem de infecções ao longo do ano. Em 2008, observam-se algumas variações atípicas. Em 2009, o número de infecções encontra-se bem distribuído ao longo do ano, mantendo uma variação sazonal relativamente constante entre os 5 e os 9%. Os Streptococcus pyogenes isolados neste hospital afectam maioritariamente crianças entre os 3 e os 5anos causando amigdalite. Quanto à variação sazonal é inconclusiva, dada a discrepância de 2008 para 2009 e a falta de dados epidemiológicos portugueses publicados sobre a bactéria em questão. Desta forma, seria importante avaliar esta variação em estudos futuros, de modo a conseguir um encadeamento lógico desta variabilidade.

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Streptococcus pyogenes can be efficiently internalized by a variety of human epithelial cells. β-lactam antibiotics, commonly used to treat S. pyogenes infections, do not readily permeate mammalian cells. There is growing evidence that the ability of streptococci to enter host cells contributes to the frequent failure of antibiotics to eradicate the organism from infected individuals. Recent studies have suggested that host cell entry requires the formation of a complex of a bacterial fibronectin (Fn) binding protein (e.g., M1 protein or protein F1/SfbI), human Fn, and the epithelial cell Fn receptor, integrin α5β1. We report here that a low molecular weight, nonpeptide antagonist of integrin α5β1, SJ755, can inhibit internalization of streptococci by primary human tonsillar epithelial cells and immortalized human epithelial (A549) cells, thus increasing the extent of bacterial killing by antibiotics. SJ755 blocked Fn binding by human tonsillar epithelial and A549 cells, suggesting that integrin α5β1 is the major Fn receptor expressed by both cell types. SJ755 did not affect Fn binding by purified M1 protein or M1+ bacteria. Purified M1 protein failed to associate with integrin α5β1 unless the integrin had been prebound by Fn. Also, SJ755 blocked formation of α5β1-Fn-M1 complexes in vitro. These results support the previous proposal that Fn functions as a molecular bridge between M1 protein and integrin α5β1. Furthermore, these results suggest that integrin antagonists may enhance the efficacy of antibiotics in treatment of S. pyogenes infections.

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Relatamos um caso de meningite por Streptococcus pyogenes em menina de 18 dias de vida, com evolução complicada por trombose de seio sagital. São discutidos alguns aspectos da patogênese, tratamento e seguimento da doença. Frente ao aumento mundial das infecções estreptocócicas graves nos últimos 10 anos, é provável que a meningite neonatal por Streptococcus pyogenes se torne mais frequente no futuro, sendo importante estar alerta para o diagnóstico precoce e as possíveis complicações dessa infecção potencialmente letal.

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O Streptococcus pyogenes (Grupo A de Lancefield) é uma bactéria Gram positiva e beta-hemolítica, responsável por infecções, tais como Faringite, Sepse, Fasciíte Necrotizante e Síndrome do Choque Tóxico Estreptocócico. Indivíduos suscetíveis podem desenvolver sequela não supurativa auto-imune pós-estreptocócica, como a Febre Reumática, Doença Reumática Cardíaca e a Glomerulonefrite Aguda. A proteína M é o principal antígeno bacteriano. Consiste em aproximadamente 450 resíduos de aminoácidos dispostos em quatro regiões (A, B, C e D), contendo alguns blocos de repetições. As regiões C e D são conservadas e a N-terminal (regiões A e B) é polimórfica. Atualmente, existem mais de 250 genótipos de emm conhecidos em todo o mundo, de acordo com o Centers for Disease Control and Prevention. Há vários anos, o desenvolvimento de uma vacina contra S. pyogenes (StreptInCor - identificação médica) foi iniciado, com base na região conservada da proteína M, com o objetivo de proteger o indivíduo vacinado contra infecções estreptocócicas, sem causar reações autoimunes. No presente estudo foi analisada a capacidade \"in vitro\" de anticorpos anti-StreptInCor neutralizarem/opsonizarem as cepas de S. pyogenes mais freqüentes em São Paulo, através da análise do reconhecimento das cepas por soros de camundongos imunizados com StreptInCor. Também foi avaliada por Western blotting a presença de anticorpos de reação cruzada dirigidos ao tecido cardíaco valvular humano. Anticorpos anti-StreptInCor foram capazes de neutralizar/opsonizar, pelo menos, cinco diferentes cepas mostrando que a imunização com StreptInCor pode ser eficaz contra várias cepas de S. pyogenes, assim como prevenir a infecção e sequelas subsequentes, sem causar reações auto-imunes.

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Background: Diseases produced by Streptoccocus pyogenes are still a problem in Chile, as in the rest of the world. It exhibits in vitro susceptibility to different antimicrobials, but penicillin continues to be the treatment of choice. Alternative drugs have been developed for allergic patients, such as erythromycin, new macrolides and cephalosporins. Nevertheless, resistant strains are appearing due to the indiscriminate use of macrolides. Aim: To assess present antimicrobial susceptibility of S Pyogenes strains isolated from chilean patients. Material and Methods: The susceptibility to penicillin, macrolides, clindamycin, cephalotin and vancomycin of 153 S Pyogenes strains, obtained from different health centers of the Metropolitan Region and isolated between 1996 and 1998, was assessed using the Kirby-Bauer method. Agar dilution minimal inhibitory concentration was then determined to macrolide resistant strains. Results: All strains were susceptible to penicillin. There was a 7.2% cross-resistance to macrolides. Conclusions: These results confirm that S Pyogenes resistance to macrolides has increased considerably in the Metropolitan Region of Chile during the last years.

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Background: The virulence of Streptococcus pyogenes is determined by a variety of structural molecules, toxins and complex enzymes. Pyrogenic exotoxins cause fever, erythematous reactions, cytotoxic and immunological effects. Aim: To assess the frequency of speA, speB and speC genes in Chilean Streptococcus pyogenes strains and their association with the invasiveness of infections. Material and methods: The genes for pyrogenic exotoxins SpeA, SpeB and SpeC were determined by polymerase chain reactions in 114 strains of group A Streptococcus pyogenes isolated from Chilean patients with invasive or non invasive infections. Results: The gene for SpeA was present in 30.7% of isolates, the gene for SpeB was present in 69.3% and the gen for SpeC in 44.7% of isolates. The gene for SpeA was present in 20 of 33 invasive infections and in 15 of 81 non invasive infections (p <0.0001). On the contrary, the gene for SpeC was present in 11 of 33 invasive infections and in 41 of 81 non invasive infections (p <0.05). The frequency of speB was similar in invasive and non invasive infections. Conclusions: There is a clear relationship between the presence of SpeA genes and the severity of infections caused by Streptococcus pyogenes. (Rev Méd Chile 2000; 128: 27-34)

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Group A Streptococcal (GAS) infections have increased in frequency and severity worldwide. During April 1996, a nosocomial outbreak associated to GAS infections affected seven patients admitted to a pediatric burn unit. The causative organism was likely disseminated from the source patient to another child in the emergency room before he was transferred to the burn unit. Patients developed burn infections or invasive disease. One of them died due to a toxic shock syndrome and 3 other lost their skin grafts. Perineal and nasal microbiological surveillance of 42 related health care workers identified only one of them as carrier of S pyogenes. Aim: To report a molecular analysis of an apparently clonal outbreak. Material and methods: The available isolates were analyzed by molecular methods including random amplified polymorphic DNA analysis (RAPD) with 4 different primers, Sma-I pulsed field gel electrophoresis (PFGE) analysis, and speA, speB and speC detection by polymerase chain reaction (PCR). Results: Two phylogenetically distant and sequentially isolated bacterial groups were identified either by RAPD analysis with selected primers or by Smal-PFGE analysis. The first group involved isolates identified in two patients that included the lethal case. The second bacterial group comprised 5 clinical isolates and the perineal and nasal isolates obtained from a health care worker. Only strains belonging to the first group harbored the speA gene and were associated with invasive disease. The second group could be split further in two subgroups according to their speB profile. Conclusions: RAPD analysis with selected primers can reproduce the PFGE-discriminating ability on the epidemiological analysis of GAS infections (Rev Méd Chile 2003; 131: 145-54)

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Recently there has been an exponential increase in invasive infections caused by Streptococcus ß hemolyticcus group A. In about one third of cases they are complicated by toxic shock syndrome, characterized by septic shock and multiorgan failure. The authors, by their rarity, report a case of bacteraemia caused by Streptococcus pyogenes complicated by toxic shock syndrome.

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Streptococcus pyogenes is responsible for a variety of infectious diseases and immunological complications. In this study, 91 isolates of S. pyogenes recovered from oropharynx secretions were submitted to antimicrobial susceptibility testing, emm typing and pulsed-field gel electrophoresis (PFGE) analysis. All isolates were susceptible to ceftriaxone, levofloxacin, penicillin G and vancomycin. Resistance to erythromycin and clindamycin was 15.4%, which is higher than previous reports from this area, while 20.9% of the isolates were not susceptible to tetracycline. The macrolide resistance phenotypes were cMLSB (10) and iMLSB (4). The ermB gene was predominant, followed by the ermA gene. Thirty-two emm types and subtypes were found, but five (emm1, emm4, emm12, emm22, emm81) were detected in 48% of the isolates. Three new emm subtypes were identified (emm1.74, emm58.14, emm76.7). There was a strong association between emm type and PFGE clustering. A variety of PFGE profiles as well as emm types were found among tetracycline and erythromycin-resistant isolates, demonstrating that antimicrobial resistant strains do not result from the expansion of one or a few clones. This study provides epidemiological data that contribute to the development of suitable strategies for the prevention and treatment of such infections in a poorly studied area.

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This study investigated the possible relationship between the invasiveness of group A Streptococcus (GAS) strains and their abilities to adhere to laminin and assessed the effects of subinhibitory concentrations of penicillin and erythromycin on the ability of GAS to adhere to laminin. The adherence of noninvasive and highly invasive isolates of GAS to laminin was significantly higher than the adherence displayed by isolates of low invasiveness. Antibiotic treatment caused significant reductions in adherence to laminin in all three groups of strains. Penicillin was more successful in reducing the adherence abilities of the tested GAS strains than erythromycin.

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La glándula parótida es generalmente afectada por procesos inflamatorios. Su etiología se debe a infecciones primarias de la glándula o como complicación de infecciones sistémicas. Se reporta el Stafilococcus aureus como el agente causal más frecuente de parotiditis aguda supurada, y se señalan además otras bacterias y virus. Se presenta un niño de 9 años de edad con un proceso supurativo agudo de la parótida izquierda de un mes de evolución, con salida de abundante pus por el conducto de Stenon. Se realizó cultivo de la secreción e identificación de Streptococcus B hemolítico grupo A, a pesar de haber recibido antibioticoterapia previa. Se utilizó ampicillina y se tuvo en cuenta la sensibilidad in vitro; no presentó mejoría clínica, por lo que se decidió el empleo de la sialografía como alternativa terapéutica en este caso. Se obtuvo la resolución del proceso supurativo infeccioso y además se evidenció en este estudio la pérdida del estroma parotídeo.

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INTRODUCCIÓN. El objetivo de la presente investigación fue describir las características clínicas y epidemiológicas de la infección por Estreptococo del grupo A en los recién nacidos egresados de hospitales maternos. MÉTODOS. Se realizó un estudio descriptivo, que incluyó a recién nacidos consecutivos, quienes tuvieron infecciones por estreptococos del grupo A y que estuvieron ingresados en el servicio de neonatología del Hospital Pediátrico Universitario «Juan M. Márquez» entre 1992 y el 2005. Se procesaron y analizaron distintas variables clínicas y epidemiológicas con cálculo de tasas de incidencia y letalidad. RESULTADOS. Se registraron 20 recién nacidos con infección por estreptococos del grupo A, lo cual representó una tasa promedio anual de 0,2 cada 100 ingresos. Esta infección muestra una incidencia con tendencia significativa a disminuir en los últimos años. Según la clasificación utilizada, todas las infecciones fueron de inicio tardío y, de acuerdo al origen, predominaron las adquiridas en la comunidad (95,0 %). La infección de tejidos blandos fue la forma clínica más frecuente (10 de 20; 50 %) y cursó con bacteriemia. Los aislamientos de estreptococos del grupo A tuvieron un 100 % de sensibilidad ante los betalactámicos. Hubo un solo paciente fallecido, afecto de meningitis, lo cual significó una tasa de letalidad del 5,0 %. CONCLUSIONES. El estreptococo del grupo A es un agente causal de infecciones que afectan al recién nacido, fundamentalmente en el ambiente comunitario. Estas infecciones pueden ser letales en algunos pacientes con infección del sistema nervioso central, a pesar del patrón de elevada susceptibilidad a los betalactámicos.