RESUMO
La faringoamigdalitis es uno de los motivos más frecuentes de consulta en pediatría. Aproximadamente un 70-80% de las faringoamigdalitis son de etiología viral. El 20-30% restante son de origen bacteriano. El agente causal más frecuente es Streptococcus pyogenes (estreptococo ß-hemolítico del grupo A). El rol de Streptococcus dysgalactiae subsp. equisimilis, (estreptococos ß-hemolíticos grupos C y G) fue claramente establecido como agente etiológico en la faringitis bacteriana, tanto en niños como en adultos. Se realizó un análisis descriptivo y retrospectivo entre enero 2018 y diciembre de 2021. Se evaluó la prevalencia de faringitis estreptocócica, la edad, el período estacional, los agentes etiológicos y la resistencia a macrólidos durante los períodos pre-COVID-19 (2018-2019) y COVID-19 (2020-2021). Se analizaron 11 396 muestras de exudados de fauces de pacientes con sospecha de faringitis bacteriana; las mismas se procesaron mediante el uso de técnicas microbiológicas convencionales. En el período estudiado el porcentaje de positividad de los cultivos de exudados de fauces se mantuvo constante. Al comparar los períodos pre-COVID-19 (2018-2019) y COVID-19 (2020-2021) se observó una disminución en el número de aislados de S. pyogenes con un aumento de S. dysgalactiae subsp. equisimilis, mientras que la resistencia a macrólidos encontrada fue superior en S. pyogenes y para S. dysgalactiae subsp. equisimilis se mantuvo constante. Es importante realizar el cultivo para la identificación del agente etiológico y determinar la sensibilidad antibióticapara continuar con la vigilancia epidemiológica de la resistencia a los macrólidos, porque representan una opción en pacientes alérgicos a ß-lactámicos (AU)
Pharyngotonsillitis is one of the most frequent reasons for consultation in children. Approximately 70-80% of pharyngotonsillitis are of viral etiology. The remaining 20-30% are bacterial in origin. The most frequent causative agent is Streptococcus pyogenes (group A ß-hemolytic streptococcus). Streptococcus dysgalactiae subsp. equisimilis (ß-hemolytic streptococcus groups C and G) was clearly established as an etiologic agent in bacterial pharyngitis in both children and adults. A descriptive and retrospective analysis was conducted between January 2018 and December 2021. The prevalence of streptococcal pharyngitis, age, seasonal period, etiologic agents, and macrolide resistance during the pre-COVID-19 (2018-2019) and COVID-19 (2020-2021) periods were evaluated. We analyzed 11 396 specimens of swabs from patients with suspected bacterial pharyngitis. Conventional microbiological techniques were used. In the study period, the percentage of positivity of swab cultures remained constant. When comparing the preCOVID-19 (2018-2019) and COVID-19 (2020-2021) periods, a decrease in the number of S. pyogenes isolates was observed with an increase in S. dysgalactiae subsp. equisimilis, while the resistance to macrolides found was higher for S. pyogenes and remained constant for S. dysgalactiae subsp. equisimilis. The identification of the etiologic agent and determination of antibiotic sensitivity are important for epidemiological surveillance of macrolide resistance, as they are a treatment option in patients who are allergic to ß-lactams (AU)
Assuntos
Humanos , Infecções Estreptocócicas/epidemiologia , Faringite/etiologia , Faringite/epidemiologia , Macrolídeos/farmacologia , Farmacorresistência Bacteriana , COVID-19 , Streptococcus pyogenes/isolamento & purificação , Estudos RetrospectivosRESUMO
Streptococcus pyogenes, Streptococcus agalactiae and Streptococcus dysgalactiae subsp. equisimilis (SDSE) are the beta-hemolytic streptococci species with the most clinical relevance to humans. These species are responsible for several infections, ranging from mild to life-threatening diseases. Although resistance to recommended drugs has not been so critical as detected in other species, it has occurred in diverse regions. In Brazil, it is possible to observe an increasing macrolide and lincosamide resistance trend due to the spread of polyclonal strains. Macrolide-lincosamide-streptogramin B (MLS) resistance phenotypes have been prevalent among S. agalactiae and S. pyogenes, while M phenotype (resistance only to macrolides) has prevailed among SDSE resistant isolates. Fluoroquinolone resistance is rare in this country, reported only in S.agalactiae and S.pyogenes. This is due to nucleotide substitutions in gyrA and parC genes. Reduced penicillin susceptibility and vancomycin resistance, detected in other regions, have not yet been reported in Brazil. Tetracycline is not a therapeutical option, and resistance has occurred at high levels, especially among S.agalactiae. These findings highlight the need for continuous monitoring in order to track the occurrence of antimicrobial resistance among beta-hemolytic streptococci species circulating in this country.
RESUMO
Últimamente, se están detectando mutaciones en las proteínas ligadoras de penicilina (PBP) de los estreptococos beta-hemolíticos que corresponden a sitios que en Streptococcus pneumoniae han determinado sensibilidad disminuida a los antibióticos beta-lactámicos. Primero, se describieron cepas con sensibilidad intermedia a penicilina en Streptococcus agalactiae (estreptococos del grupo B), luego en Streptococcus dysgalactiae subsp. equisimilis (mayormente grupos C y G) y, más recientemente, cepas con sensibilidad disminuida a aminopenicilinas y cefalosporinas de tercera generación en Streptococcus pyogenes (grupo A). El costo biológico de estas modificaciones nos permite pensar que los niveles de resistencia no han de ser tan elevados como para comprometer por ahora la efectividad clínica de los beta-lactámicos (AU)
Recently, mutations in penicillin-binding proteins (PBPs) of beta-hemolytic streptococci have been detected corresponding to sites that in Streptococcus pneumoniae have been determined to have decreased sensitivity to beta-lactam antibiotics. First, strains with intermediate sensitivity to penicillin were described in Streptococcus agalactiae (group B streptococci), subsequently in Streptococcus dysgalactiae subsp. equisimilis (mainly groups C and G) and, more recently, strains with decreased sensitivity to third-generation aminopenicillins and cephalosporins were found in Streptococcus pyogenes (group A). The biological cost of these modifications suggests that, for now, resistance levels are not high enough to compromise the clinical effectiveness of beta-lactams (AU)
Assuntos
Streptococcus agalactiae/efeitos dos fármacos , Streptococcus pyogenes/efeitos dos fármacos , Resistência às Penicilinas , Testes de Sensibilidade Microbiana , Resistência beta-Lactâmica , beta-Lactamas/farmacologia , Antibacterianos/farmacologiaRESUMO
Introduction. In some species, the population structure of pathogenic bacteria is clonal. However, the mechanisms that determine the predominance and persistence of specific bacterial lineages of group C Streptococcus remain poorly understood. In Brazil, a previous study revealed the predominance of two main lineages of Streptococcus dysgalactiae subsp. equisimilis (SDSE).Aim. The aim of this study was to assess the virulence and fitness advantages that might explain the predominance of these SDSE lineages for a long period of time.Methodology. emm typing was determined by DNA sequencing. Adhesion and invasion tests were performed using human bronchial epithelial cells (16HBE14o-). Biofilm formation was tested on glass surfaces and the presence of virulence genes was assessed by PCR. Additionally, virulence was studied using Caenorhabditis elegans models and competitive fitness was analysed in murine models.Results. The predominant lineages A and B were mostly typed as emm stC839 and stC6979, respectively. Notably, these lineages exhibited a superior ability to adhere and invade airway cells. Furthermore, the dominant lineages were more prone to induce aversive olfactory learning and more likely to kill C. elegans. In the competitive fitness assays, they also showed increased adaptability. Consistent with the increased virulence observed in the ex vivo and in vivo models, the predominant lineages A and B showed a higher number of virulence-associated genes and a superior ability to accumulate biofilm.Conclusion. These results suggest strongly that this predominance did not occur randomly but rather was due to adaptive mechanisms that culminated in increased colonization and other bacterial properties that might confer increased bacteria-host adaptability to cause disease.
Assuntos
Biodiversidade , Infecções Estreptocócicas/microbiologia , Streptococcus/patogenicidade , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Brasil , Caenorhabditis elegans , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Streptococcus/classificação , Streptococcus/genética , Streptococcus/isolamento & purificação , VirulênciaRESUMO
Group A (GAS), B (GBS), c (GCS) and G (GGS) β-hemolytic streptococci are important human pathogens. They cause infections of different severity and frequency. Nowadays, after 70 years of use, penicillin is still universally active against GAS, GCS and GGS. However, therapeutic failures have been recorded in 2-28% of pharyngitis cases (median: 12%) attributable to different causes. By contrast, some GBS with reduced susceptibility to penicillin have been described, especially in Japan. In this group of bacteria, it is important to highlight that confirmation by reference methods is mandatory when decreased susceptibility to penicillin is suspected as well as checked for the detection of the mechanisms involved.
Los estreptococos β-hemolíticos de los grupos A (GAS), B (GBS), C (GCS) y G (GGS) son importantes patógenos humanos. Ellos producen infecciones de diversa gravedad y frecuencia. Aún después de más de 70 años de uso, la penicilina sigue siendo activa in vitro frente al 100% de los GAS, GCS y GGS. No obstante se han producido fallas terapéuticas entre el 2-28% de los casos de faringitis (media: 12%), atribuibles a diversas causas. En cambio se han descrito aislados de GBS con sensibilidad reducida a la penicilina, especialmente en Japón. Es importante que toda sospecha de sensibilidad disminuida a la penicilina en este grupo de bacterias sea confirmada por los métodos de referencia y comprobada mediante la detección de los mecanismos involucrados.
Assuntos
Humanos , Streptococcus/efeitos dos fármacos , beta-Lactamas/farmacologia , Testes de Sensibilidade Microbiana , Farmacorresistência BacterianaRESUMO
Group A (GAS), B (GBS), C (GCS) and G (GGS) ß-hemolytic streptococci are important human pathogens. They cause infections of different severity and frequency. Nowadays, after 70 years of use, penicillin is still universally active against GAS, GCS and GGS. However, therapeutic failures have been recorded in 2-28% of pharyngitis cases (median: 12%) attributable to different causes. By contrast, some GBS with reduced susceptibility to penicillin have been described, especially in Japan. In this group of bacteria, it is important to highlight that confirmation by reference methods is mandatory when decreased susceptibility to penicillin is suspected as well as checked for the detection of the mechanisms involved.
Assuntos
Streptococcus/efeitos dos fármacos , beta-Lactamas/farmacologia , Farmacorresistência Bacteriana , Humanos , Testes de Sensibilidade MicrobianaRESUMO
La faringitis aguda bacteriana (FAB) representa entre un 20 a 30% de las faringitis. El principal agente causal es Streptococcus pyogenes. Se revisó retrospectivamente la información microbiológica disponible entre 2010 y 2016, para analizar la incidencia de la FAB, sus agentes causales, la incidencia de casos según el período estacional y rango etario. Se determinó el porcentaje de resistencia (R) de S. pyogenes a eritromicina y el fenotipo predominante. Se diagnosticó FAB en 21,5% de 3.246 cultivos, donde 89% fueron causados por S. pyogenes. El 35,3% de las FAB se presentó en niños de 7 a 10 años, seguido por el grupo de mayores de 15 años (31,3%). Se evidenció un aumento de faringitis por Streptococcus dysgalactiae subsp. equisimilis en 2011 y 2014; 56,2% de los casos se diagnosticaron en mayores de 15 años. Hubo 3 casos de FAB por Arcanobacterium haemolyticum. El 36,1% de las faringitis se presentaron en primavera, con un aumento significativo durante las correspondientes a 2010 y 2016. La R global a eritromicina en S. pyogenes fue del 16,6% con predominio del fenotipo M. El valor de R encontrado fue superior al ser comparado con otras estadísticas similares, lo que demostró la importancia de monitorear este dato, dado que es el antibiótico alternativo en pacientes alérgicos a penicilina.
Acute bacterial pharyngitis (ABP) accounts for 20 to 30% of acute pharyngitis. The most common bacterial agent is Streptococcus pyogenes. A retrospective, record-based study was carried out based on the microbiological records from 2010 to 2016, analyzing ABP's incidence, its causal agents and its incidence according to the season and age range. Erythromycin resistance and the main resistance phenotype were determined in S. pyogenes. Acute bacterial pharyngitis was diagnosed in 21.5% out of 3.246 cultures, 89% were due to S. pyogenes, 36.3% of patients were children between 7 to 10 years old and 31.3% were older than 15 years of age. There was a significant increase in pharyngitis due to Streptococcus dysgalactiae subsp. equisimilis since 2010 (p<0.05), 52.5% were detected in patients older than 15 years of age. There were only three cases of ABP produced by Arcanobacterium haemolyticum. A total of 36.1% of pharyngitis occurred during spring, with a significant increase during 2010 and 2016 springs. Global erythromycin resistance in S. pyogenes was 16.6% with predominance of the M phenotype. This resistance rate is higher than that described in other similar series, demonstrating the importance of continuously monitoring of macrolide R in S. pyogenes, since they are the antibiotics of choice to treat pharyngitis in patients allergic to penicillin.
A faringite bacteriana aguda (FAB) representa entre 20 e 30% das faringites. O principal agente causador é Streptococcus pyogenes. Foi revista retrospectivamente a informação microbiológica disponível entre 2010 e 2016, para analisar a incidência da FAB, seus agentes causadores, a incidência de casos de acordo com o período sazonal e a faixa etária. A percentagem de resistência (R) de S. pyogenes à eritromicina e ao fenótipo predominante foram determinadas. Foi diagnosticado FAB em 21,5% de 3,246 culturas, 89% das quais foram causadas por S. pyogenes. 35,3% das FAB se apresentou em crianças de 7 a 10 anos, seguidas pelo grupo de mais de 15 anos (31,3%). Houve aumento de faringite por Streptococcus dysgalactiae subsp. equisimilis em 2011 e 2014; 56,2% dos casos foram diagnosticados em jovens de mais de 15 anos. Houve 3 casos de FAB por Arcanobacterium haemolyticum. 36,1% das faringites ocorreu na primavera, com um aumento significativo em 2010 e 2016. A R global a eritromicina em S. pyogenes foi de 16,6% com prevalência do fenótipo M. O valor de R encontrado foi superior em comparação com outras estatísticas semelhantes, demonstrando a importância de monitorar esse dado, pois é o antibiótico alternativo em pacientes alérgicos à penicilina.
Assuntos
Humanos , Faringite/epidemiologia , Faringite/microbiologia , Streptococcus pyogenes , Arcanobacterium , Eritromicina , Faringite , Infecções RespiratóriasRESUMO
Streptococcus dysgalactiae subsp. equisimilis (SDSE) has virulence factors similar to those of Streptococcus pyogenes. Therefore, it causes pharyngitis and severe infections indistinguishable from those caused by the classic pathogen. The objectives of this study were: to know the prevalence of SDSE invasive infections in Argentina, to study the genetic diversity, to determine the presence of virulence genes, to study antibiotic susceptibility and to detect antibiotic resistance genes. Conventional methods of identification were used. Antibiotic susceptibility was determined by the disk diffusion and the agar dilution methods and the E-test. Twenty eight centers from 16 Argentinean cities participated in the study. Twenty three isolates (16 group G and 7 group C) were obtained between July 1 2011 and June 30 2012. Two adult patients died (8.7%). Most of the isolates were recovered from blood (60.9%). All isolates carried speJ and ssa genes. stG62647, stG653 and stG840 were the most frequent emm types. Nineteen different PFGE patterns were detected. All isolates were susceptible to penicillin and levofloxacin, 6 (26.1%) showed resistance or reduced susceptibility to erythromycin --#91;1 mef(A), 3 erm(TR), 1 mef(A) + erm(TR) and 1 erm(TR) + erm(B)--#93; and 7 (30.4%) were resistant or exhibited reduced susceptibility to tetracycline --#91;2 tet(M), 5 tet(M) + tet(O)--#93;. The prevalence in Argentina was of at least 23 invasive infections by SDSE. A wide genetic diversity was observed. All isolates carried speJ and ssa genes. Similarly to other studies, macrolide resistance (26.1%) was mainly associated to the MLS B phenotype.
Streptococcus dysgalactiae subsp. equisimilis (SDSE) posee factores de virulencia similares a Streptococcus pyogenes y, en consecuencia, produce faringitis e infecciones graves indistinguibles de las generadas por este patógeno clásico. Los objetivos del estudio fueron conocer la prevalencia de SDSE en infecciones invasivas en Argentina, estudiar su diversidad genética, determinar la presencia de genes de virulencia, ensayar su sensibilidad a los antibióticos y conocer los genes de resistencia. Se emplearon métodos convencionales de identificación. La sensibilidad se determinó por difusión, Etest y dilución en agar. Participaron 28 centros de 16 ciudades argentinas. Se obtuvieron 23 aislamientos (16 del grupo G y 7 del grupo C) desde el 1-7-2011 hasta el 30-6-2012. Se registraron 2 muertes en adultos (8,7%). La mayoría de los aislamientos fueron obtenidos de sangre (60,9%). Todos eran portadores de los genes speJ y ssa. Los genotipos más frecuentes fueron stG62647, stG653 y stG840. Se detectaron 19 pulsotipos distintos. Todos los aislamientos fueron sensibles a penicilina y levofloxacina, 6 (26,1%) presentaron resistencia o sensibilidad disminuida a eritromicina (1 mef--#91;A--#93;, 3 erm--#91;TR--#93;, 1 mef--#91;A--#93; + erm--#91;TR--#93; y 1 erm--#91;TR--#93; + erm--#91;B--#93;) y 7 (30,4%) fueron resistentes o tuvieron sensibilidad disminuida a tetraciclina (2 tet--#91;M--#93;, 5 tet--#91;M--#93; + tet--#91;O--#93;). La prevalencia anual en la Argentina fue de al menos 23 infecciones invasivas por SDSE y se observó una amplia diversidad genética. Todos los aislamientos presentaron los genes ssa y speJ. Como en otros estudios, la resistencia a macrólidos (26,1%) estuvo asociada, principalmente, al fenotipo MLS B.
Assuntos
Humanos , Masculino , Feminino , Infecções Estreptocócicas/classificação , Streptococcus/isolamento & purificação , Streptococcus/patogenicidade , Argentina , Streptococcus/genética , Resistência Microbiana a Medicamentos , Estudos Transversais/métodosRESUMO
BACKGROUND: Streptococcus dysgalactiae subsp. equisimilis (SDSE) has been increasingly associated with several infectious diseases, ranging from pharyngitis to life-threatening conditions, such as necrotizing fasciitis and streptococcal toxic shock syndrome. However, its molecular epidemiology in some geographical areas remains unclear. METHODS: In this study, 44 isolates of SDSE, recovered from noninvasive infections (37) and from carriage (7), during 2008-2013, were submitted to antimicrobial susceptibility testing, emm typing and pulsed-field gel electrophoresis (PFGE) analysis. RESULTS: All isolates were susceptible to ceftriaxone, levofloxacin, penicillin G and vancomycin. Resistance rates to erythromycin was 18.2% and to clindamycin was 6.8%, while 38.7% of the isolates were tetracycline non-susceptible. Macrolide resistance phenotypes were M (5 isolates), iMLSB (2) and cMLSB (1), associated with mefA/E, ermA and ermB genotypes, respectively. Seventeen emm types with 21 subtypes were found, but 6 types (stG653.0, stC1400.0 with three subtypes, stC839.0, stC36.0 with two subtypes, stG480.0 and stG840.0) were detected in 70.4% of the isolates. Six new emm subtypes were identified (stC1400.12, stC1400.13, emm152.1, emm152.2, stG652.6 and stG6792.5). Twenty-five PFGE profiles were obtained from 39 isolates. CONCLUSIONS: Congruence between both typing systems was observed, since the majority of isolates belonging to a given emm type clustered together by PFGE. Clones (at least 80% similarity) were also observed among isolates with different emm types, probably due to horizontal recombination of the emm gene. Erythromycin-resistant isolates harbored diverse emm genes and generated different PFGE profiles, showing a polyclonal dissemination of such characteristic among SDSE isolates.
Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Infecções Estreptocócicas/microbiologia , Streptococcus/efeitos dos fármacos , Streptococcus/genética , Adolescente , Adulto , Idoso , Brasil , Criança , Pré-Escolar , Eletroforese em Gel de Campo Pulsado , Humanos , Lactente , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Orofaringe/microbiologia , Adulto JovemRESUMO
Streptococcus dysgalactiae subsp. equisimilis (SDSE) has virulence factors similar to those of Streptococcus pyogenes. Therefore, it causes pharyngitis and severe infections indistinguishable from those caused by the classic pathogen. The objectives of this study were: to know the prevalence of SDSE invasive infections in Argentina, to study the genetic diversity, to determine the presence of virulence genes, to study antibiotic susceptibility and to detect antibiotic resistance genes. Conventional methods of identification were used. Antibiotic susceptibility was determined by the disk diffusion and the agar dilution methods and the E-test. Twenty eight centers from 16 Argentinean cities participated in the study. Twenty three isolates (16 group G and 7 group C) were obtained between July 1 2011 and June 30 2012. Two adult patients died (8.7%). Most of the isolates were recovered from blood (60.9%). All isolates carried speJ and ssa genes. stG62647, stG653 and stG840 were the most frequent emm types. Nineteen different PFGE patterns were detected. All isolates were susceptible to penicillin and levofloxacin, 6 (26.1%) showed resistance or reduced susceptibility to erythromycin [1 mef(A), 3 erm(TR), 1 mef(A)+erm(TR) and 1 erm(TR)+erm(B)] and 7 (30.4%) were resistant or exhibited reduced susceptibility to tetracycline [2 tet(M), 5 tet(M)+tet(O)]. The prevalence in Argentina was of at least 23 invasive infections by SDSE. A wide genetic diversity was observed. All isolates carried speJ and ssa genes. Similarly to other studies, macrolide resistance (26.1%) was mainly associated to the MLSB phenotype.
Assuntos
Bacteriemia/microbiologia , Infecções Estreptocócicas/microbiologia , Streptococcus/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Argentina/epidemiologia , Artrite Infecciosa/epidemiologia , Artrite Infecciosa/microbiologia , Bacteriemia/epidemiologia , Líquidos Corporais/microbiologia , Criança , Pré-Escolar , DNA Bacteriano/genética , Farmacorresistência Bacteriana Múltipla/genética , Eletroforese em Gel de Campo Pulsado , Feminino , Genes Bacterianos , Variação Genética , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Prevalência , Infecções dos Tecidos Moles/epidemiologia , Infecções dos Tecidos Moles/microbiologia , Infecções Estreptocócicas/epidemiologia , Streptococcus/efeitos dos fármacos , Streptococcus/isolamento & purificação , Streptococcus/patogenicidade , Streptococcus pyogenes/genética , Streptococcus pyogenes/isolamento & purificação , Virulência , Adulto JovemRESUMO
A mutant designated NC2168, which was selected from wild-type Streptococcus equisimilis CVCC55116by ultraviolet ray combined with60Co-γ ray treatment and does not produce streptolysin, was employed to produce hyaluronic acid (HA). In order to increase the output of HA in a flask, the culture medium and conditions for NC2168 were optimized in this study. The influence of culture medium ingredients including carbon sources, nitrogen sources and metal ions on HA production was evaluated using factional factorial design. The mathematical model, which represented the effect of each medium component and their interaction on the yield of HA, was established by the quadratic rotary combination design and response surface method. The model estimated that, a maximal yield of HA could be obtained when the concentrations of yeast extract, peptone, glucose, and MgSO4 were set at 3 g/100 mL, 2 g/100 mL, 0.5 g/100 mL and 0.15 g/100 mL, respectively. Compared with the values obtained by other runs in the experimental design, the optimized medium resulted in a remarkable increase in the output of HA and the maximum of the predicted HA production was 174.76 mg/L. The model developed was accurate and reliable for predicting the production of HA by NC2168.Cultivation conditions were optimized by an orthogonal experimental design and the optimal conditions were as follows: temperature 33ºC, pH 7.8, agitation speed 200 rpm, medium volume 20 mL.
Assuntos
Animais , Ácido Hialurônico/análise , Ácido Hialurônico/isolamento & purificação , Estreptolisinas/análise , Estreptolisinas/efeitos adversos , Meios de Cultura/isolamento & purificação , Infecções Estreptocócicas , Streptococcus equi/isolamento & purificação , Microbiologia Industrial , MétodosRESUMO
A mutant designated NC2168, which was selected from wild-type Streptococcus equisimilis CVCC55116by ultraviolet ray combined with60Co-γ ray treatment and does not produce streptolysin, was employed to produce hyaluronic acid (HA). In order to increase the output of HA in a flask, the culture medium and conditions for NC2168 were optimized in this study. The influence of culture medium ingredients including carbon sources, nitrogen sources and metal ions on HA production was evaluated using factional factorial design. The mathematical model, which represented the effect of each medium component and their interaction on the yield of HA, was established by the quadratic rotary combination design and response surface method. The model estimated that, a maximal yield of HA could be obtained when the concentrations of yeast extract, peptone, glucose, and MgSO4 were set at 3 g/100 mL, 2 g/100 mL, 0.5 g/100 mL and 0.15 g/100 mL, respectively. Compared with the values obtained by other runs in the experimental design, the optimized medium resulted in a remarkable increase in the output of HA and the maximum of the predicted HA production was 174.76 mg/L. The model developed was accurate and reliable for predicting the production of HA by NC2168.Cultivation conditions were optimized by an orthogonal experimental design and the optimal conditions were as follows: temperature 33ºC, pH 7.8, agitation speed 200 rpm, medium volume 20 mL.(AU)
Assuntos
Streptococcaceae/classificação , Mutação/genética , Produção de Produtos , Ácido Hialurônico/administração & dosagemRESUMO
A mutant designated NC2168, which was selected from wild-type Streptococcus equisimilis CVCC55116 by ultraviolet ray combined with(60)Co-γ ray treatment and does not produce streptolysin, was employed to produce hyaluronic acid (HA). In order to increase the output of HA in a flask, the culture medium and conditions for NC2168 were optimized in this study. The influence of culture medium ingredients including carbon sources, nitrogen sources and metal ions on HA production was evaluated using factional factorial design. The mathematical model, which represented the effect of each medium component and their interaction on the yield of HA, was established by the quadratic rotary combination design and response surface method. The model estimated that, a maximal yield of HA could be obtained when the concentrations of yeast extract, peptone, glucose, and MgSO4 were set at 3 g/100 mL, 2 g/100 mL, 0.5 g/100 mL and 0.15 g/100 mL, respectively. Compared with the values obtained by other runs in the experimental design, the optimized medium resulted in a remarkable increase in the output of HA and the maximum of the predicted HA production was 174.76 mg/L. The model developed was accurate and reliable for predicting the production of HA by NC2168.Cultivation conditions were optimized by an orthogonal experimental design and the optimal conditions were as follows: temperature 33°C, pH 7.8, agitation speed 200 rpm, medium volume 20 mL.
RESUMO
La infección por Streptococcus dysgalactiae subsp equisimilis es causa frecuente de faringitis, artritis e infecciones de piel y tejidos blandos; excepcionalmente se ha descrito como causa de endocarditis infecciosa. Se presenta el caso de un paciente masculino de 42 años quien ingresa al Hospital Vargas de Caracas con fiebre, astenia, dolor en hombro derecho con limitación funcional y dolor en hipocondrio derecho; a las 48 horas se evidencia soplo mesosistólico en foco mitral, hemorragias en astillas y lesiones de Janeway, por lo que se plantea Endocarditis Infecciosa, y se inicia tratamiento con Vancomicina + Gentamicina. Los hemocultivos muestran crecimiento de Streptococcus equisimilis en ambos frascos; el ecocardiograma transtorácico evidencia una vegetación en valva posterior de válvula mitral. Luego de 48 horas de inicio de tratamiento remite la fiebre. El ecocardiograma control a los 14 días mostró la desaparición de la vegetación en la válvula mitral. El paciente recibió tratamiento por 6 semanas
Streptococcus dysgalactiae subsp equisimilis is frequent in patients with pharyngitis, arthritis and skin infections; it rarely causes infective endocarditis. We describe a 42 year-old male patient complaining of fever, malaise, right shoulder pain and right upper quadrant pain who was admitted to the Hospital Vargas, Caracas, Venezuela. After 48 hours his physical examination revealed mesosystolic murmur at the apex, splinter hemorrhages and Janeway lesions, suggestive of Infective Endocarditis Blood cultures identified Streptococcus equisimilis; transthoracic echocardiogram revealed a vegetation over the posterior leaflet of mitral valve; the patient was treated with Vancomycin + Gentamycin. After 48 hours of treatment the fever subsided. A transthoracic echocardiogram after 14 days showed no vegetations. The patient was treated during 6 weeks
Assuntos
Humanos , Masculino , Adulto , Artrite/patologia , Ecocardiografia/métodos , Endocardite/diagnóstico , Faringite/patologia , Gentamicinas , Infecções Cutâneas Estafilocócicas/patologia , Infecções dos Tecidos Moles/patologia , Streptococcus/patogenicidade , VancomicinaRESUMO
The beta-hemolytic group C streptococci (Lancefield's group) has been considered an emergent human pathogen, showing an important role as an opportunist agent, being responsible for nosocomial infections and outbreaks. This study is reporting the first outbreak of nosocomial infection caused by Streptococcus dysgalactiae subsp. equisimilis in Brazil. From January, 2002, to December, 2004, S. equisimilis was isolated in 67/207 (32.37%) samples from secretions of patients' infected wounds, interned at the Hospital of Sanitary Dermatology in the State of Paraná (HDSPR). The prevalence of this microorganism increased from 11/42 (26.19%) in 2002, 14/65 (21.54%) in 2003 to 42/100 (42.00%) in 2004. This increase was statistically significant (p=0.024), and this microorganism became the most frequently isolated in these patients, overtaking the rates of isolation of Pseudomonas aeruginosa. The S. equisimilis grew in pure culture, as a unique microorganism, in six samples (2.9%) out of 207. Fresh feces of 15 animals (horses and sheep) living in the proximities of the hospital were also examined and three of them positive for S. equisimilis. The biochemical profile of the strains isolated from the patients and from the animals was the same. These animals might have been the source of the dissemination of the outbreak in the hospital. New studies will be necessary to confirm the genetic relationship between the strains isolated from patients and animals.
O estreptococo beta-hemolítico do grupo C de Lancefield tem sido considerado patógeno humano emergente, mostrando importante papel como agente oportunista, implicado algumas vezes em infecções hospitalares e surtos. Este estudo está relatando o primeiro surto de infecção hospitalar causado pelos Streptococcus dysgalactiae subsp. equisimilis no Brasil. De janeiro de 2002 a dezembro de 2004, isolou-se S. equisimilis em 67/207 (32,37%) das amostras de secreções de lesões de feridas coletadas de pacientes internados no Hospital de Dermatologia Sanitária do Paraná (HDSPR). A prevalência deste microrganismo aumentou de 11/42 (26,19%) em 2002, 14/65 (21,54%) em 2003 para 42/100 (42,00%) em 2004. Este aumento foi estatisticamente significante (p=0.024), tornando este microrganismo o mais freqüentemente isolado nos pacientes, ultrapassando as taxas de isolamento de Pseudomonas aeruginosa. Em seis amostras (2,9%) entre as 207 examinadas, S. equisimilis cresceu em cultivo puro, como único microrganismo. Também foram examinadas fezes frescas de 15 animais (cavalos e ovelhas) que vivem nas proximidades do hospital, e três amostras foram positivas para S. equisimilis. O perfil bioquímico encontrado entre os isolados dos pacientes foi o mesmo encontrado entre os isolados das fezes dos animais. Acredita-se que estes animais possam ter sido a fonte de disseminação do surto no hospital. Novos estudos serão necessários para confirmar o relacionamento genético entre os isolados dos pacientes e animais.