Infecciones por estreptococos del grupo S. anginosus en pediatría / S. anginosus group streptococcal infections in children

Los estreptococos del grupo Streptococcus anginosus (EGA), también llamados "Streptococcus milleri", fueron reconocidos como parte de los estreptococos del grupo viridans (EGV) desde principios del siglo XX. Su rol como patógenos humanos, sin embargo comenzó a destacarse recién en la década de 1970. En esta actualización se describen aspectos microbiológicos y clínicos de los EGA. Los métodos fenotípicos de identificacón e incluso algunos genotípicos carecen de precisión para reconocer las tres especies del grupo (Streptococcus anginosus, Streptococcus constellatus y Streptococcus intermedius) e incluso pueden fallar en su clasificación a nivel de grupo. La mayoría de ellos son sensibles a los antibióticos beta-lactámicos pero son considerables los porcentajes de resistencia a macrólidos, lincosamidas y tetraciclinas. Los EGA son colonizantes habituales de las mucosas orofaríngea, intestinal y genitourinaria, pero, cada vez más frecuentemente, son reconocidos como patógenos humanos. Es ampliamente conocida su capacidad de formar abscesos en órganos sólidos, especialmente abscesos cerebrales, pulmonares y hepáticos. También producen sinusitis, empiemas y colecciones en piel y tejidos blandos, hueso, articulaciones, etc. Se han encontrado asociados con exacerbaciones pulmonares en pacientes con fibrosis quística y con enfermedad pulmonar obstructiva crónica. Producen también infecciones posteriores a mordeduras humanas, infecciones diseminadas, bacteriemia sin foco aparente y, en menor medida, endocarditis infecciosa (AU)

Streptococci from the Streptococcus anginosus group (SAG), also termed "Streptococcus milleri", were recognized as members of the viridans group streptococci (VGS) in the early 20th century. Nevertheless, their role as human pathogens only became evident in the 1970s. In this update, microbiological and clinical aspects of the SAG are described. Phenotypic and even some genotypic identification methods lack accuracy in recognizing the three species of the group (Streptococcus anginosus, Streptococcus constellatus, and Streptococcus intermedius) and may fail to classify them at the group level. Most of them are sensitive to beta-lactam antibiotics but rates of resistance to macrolides, lincosamides, and tetracyclines are significant. SAGs are common colonizers of the oropharyngeal, intestinal, and genitourinary mucosa, but are increasingly recognized as human pathogens. Their ability to form abscesses in solid organs, especially brain, lung and liver, is widely known. They may produce sinusitis, empyemas, and collections in skin and soft tissues, bone, joints, etc. They have also been associated with pulmonary exacerbations in patients with cystic fibrosis and chronic obstructive pulmonary disease. In addition, they may cause infections following human bites, disseminated infections, bacteremia without apparent focus, and, to a lesser extent, infective endocarditis (AU)

Perfil antibiótico de estreptococos del grupo viridans aislados de cavidad oral en individuos con uso prolongado de antibióticos / Antibiotic profile of viridans streptococci group isolated of oral cavity from patients with prolonged use of antibiotics

RESUMEN Los estreptococos del grupo viridans (EGV) son un grupo heterogéneo de bacterias saprófitas anaerobias facultativas que forman parte de la flora normal de cavidad oral. El incremento de la resistencia antibiótica de este grupo de bacterias cobra importancia en pacientes hospitalizados con terapia antibiótica prolongada, en los cuales estos microorganismos pueden ser sustituidos por bacterias multirresistentes. Objetivos: Determinar el porcentaje de cepas de EGV aisladas de cavidad oral resistentes a los antibióticos utilizados en el tratamiento de diversas patologías infecciosas hospitalarias. Material y Métodos: Estudio observacional descriptivo en el que se incluyeron 60 pacientes hospitalizados con historia de terapia antibiótica por más de 3 semanas. Las muestras se procesaron siguiendo protocolos estandarizados de recolección, aislamiento e identificación para EGV de cavidad oral y un protocolo de pruebas de sensibilidad antibiótica. Los resultados se muestran en tablas y gráficas de frecuencia. Resultados: La principal indicación para terapia antibiótica intrahospitalaria fue infección orofacial: 28,33%. La penicilina fue el antibiótico más utilizado ya sea en terapia única, combinada o múltiple en todos los pacientes. Se aislaron en total 108 cepas de EGV, con un promedio de 1,8 cepas por paciente. La especie predominantemente identificada fue S. mutans. El 96,3% de las cepas de EGV fue sensible a todos los antibióticos incluidos en el panel. Conclusiones: El uso de distintas combinaciones y modalidades de terapia antibiótica no tiene efecto en la susceptibilidad de EGV aislados de cavidad oral en pacientes hospitalizados, independiente de la duración del tratamiento.

ABSTRACT Viridans group streptococci (VGS) are a heterogeneous group of saprophytic facultative anaerobic bacteria that are part of the normal flora of the oral cavity. The increased resistance to multiple antibiotics in this group of bacteria becomes important in prolonged antibiotic therapies inpatient where these common microorganisms are replaced by multi-resistant bacteria. Objectives: To determine the percentage of VGS strains isolated from oral cavity resistant to antibiotics used in hospital infectious diseases. Material and methods: This is a descriptive cross-sectional study that included 60 hospitalized patients with a history of antibiotic therapy for more than 3 weeks. The samples were processed following standardized protocols for collection, isolation and identification of oral cavity VGS and a protocol of antibiotic susceptibility testing. The results are shown in tables and graphics of absolute and relative frequencies. Results: The main indication for antibiotic therapy was orofacial infection with a 28.33%. Penicillin was the antibiotic further used either in single, combined or multiple therapies in all patients. A total of 108 samples (1.8 per patient swabs) were collected. The predominantly identified specie was Streptococcus mutans. The 96.3% of all VGS strains were sensitive to all antibiotics included in the panel. Conclusion: Using different combinations and types of antibiotic therapy inpatient has no effect on the susceptibility of VGS isolated from oral cavity separate from treatment.

Endocarditis infecciosa nativa en pediatría: enfoque clínico cardiológico / Native valve infective endocarditis in children: From the focus of clinical cardiology

Objetivos: Analizar las características demográficas, clínicas, microbiológicas, evolución y factores de riesgo de morbimortalidad asociados a la endocarditis de válvula nativa (EIN) en pacientes (p) pediátricos. Población y métodos: Se evaluaron 176 p con EIN, divididos en grupo I: <3meses (27p) y grupo II: >3meses (149p). Resultados: Grupo I: el 66% tenía corazón sano. El microorganismo más frecuente fue Staphylococcus aureus (44,4%). Afectación derecha (77,8%-p<0,0001). Evento principal: infección no controlada (INC) (52%, p=0,0009) y asociada a Candida (p<0,00001). Se indicó tratamiento quirúrgico a 10 p (37%). Mortalidad 29,6%(8p). Grupo II: el 57% presentaba cardiopatía previa. Microorganismos prevalentes: S.aureus (49,1%) y estreptococos del grupo viridans (22,5%). Hubo compromiso predominantemente izquierdo (p=0,001). Eventos: embolias sistémicas (36,2%-p=0,01), perforación valvular (51%-p=0,0005), insuficiencia cardíaca (26%-p=0,03) e INC (21,5%). La embolia sistémica se asoció a S.aureus (p=0,01). El 36,2% requirió cirugía. Mortalidad 6,7% (10p). En el análisis univariado la mortalidad se asoció a edad <3meses (p=0,0003), INC (p=0,002) y S.aureus (p=0,03). En el multivariado la mortalidad se relacionó a edad < 3meses (OR:7,50 ­IC95%:1,77­31,69) y a INC (OR:4,2-IC95%:1,16­15,29). Conclusiones: La EN se presentó en pacientes con corazón sano en el 50% de los casos. El microorganismo más frecuente fue S.aureus. En los <3 meses la infección no controlada fue la complicación más frecuente asociada a Candida, con afectación predominante de cavidades derechas. Los >3meses tuvieron mayor prevalencia de perforación valvular izquierda asociada a embolias sistémicas e insuficiencia cardíaca. El 35% de los p requirió cirugía. Los predictores de mortalidad fueron la edad <3meses y la INC.

Objectives: To analyze demographic, clinical, and microbiological, outcome, and morbidity and mortality risk factors associated with native valve endocarditis (NVE) in pediatric patients (p). Population and methods: 176 p with NVE were evaluated and divided into group I: <3 months (27p) and group II: >3 months (149p). Results: Group I: 66% had a healthy heart. The most common microorganism was Staphylococcus aureus (44.4%). Right-sided involvement (77.8%-p<0.0001). Main event: Uncontrolled infection (UCI) (52%, p-0.0009) and association with Candida (p<0.00001). Surgical treatment was indicated in 10 p (37%). Mortality was 29.6% (8p). Group II: 57% had previous heart disease. Prevalent microorganisms: S. aureus (49.1%) and viridans group streptococci ( (22.5%). Left-sided involvement predominated (p-0.001). Events: systemic embolism (36.2%-p-0.01), valve perforation (51%-p-0.0005), heart failure (26%-p-0.03), and UCI (21.5%). Systemic embolism was associated with S. aureus infection (p-0.01). 36.2% required surgery. Mortality was 6.7% (10p). In univariate analysis, mortality was associated with age <3 months (p-0.0003), UCI (p-0.002), and S. aureus infection (p-0.03). In multivariate analysis, mortality was related to age <3 months (OR:7.50 ­ 95% CI:1.77­31.69) and UCI (OR:4.2 -95% CI:1.16­15.29). Conclusions: NVE was observed in patients with a healthy heart in 50% of cases. The most common microorganism found was S. aureus. In the <3 months group, uncontrolled infection was the most common complication associated with Candida, predominantly affecting the right side. The >3 months group had a higher prevalence of left-valve perforation associated with systemic embolism and heart failure. 35% of p required surgery. Predictors of mortality were age <3 months and UC (AU)

Identificación y sensibilidad a los antimicrobianos de aislados de estreptococos del grupo viridans provenientes de pacientes internados en un hospital universitario de la ciudad de Buenos Aires / Identification and antibiotic susceptibility of viridans group streptococci isolates recovered from patients hospitalized at a teaching hospital in Buenos Aires City

Los estreptococos del grupo viridans (EGV) son agentes causales de infecciones localizadas e invasivas. Dada la gravedad de las infecciones producidas por EGV sumada a las escasas comunicaciones actuales en nuestro país, los objetivos de este trabajo fueron la identificación y el estudio de la sensibilidad a los antibióticos de aislados caracterizados como EGV, recuperados de pacientes internados, para actualizar el conocimiento sobre el perfil de resistencia y la epidemiología de las infecciones ocasionadas por EGV. Se recuperaron 132 aislados de EGV en el Hospital de Clínicas «José de San Martín¼ en el período 2011-2015. La identificación se realizó mediante pruebas convencionales y espectrometría de masas (Matrix Assisted Laser Desorption Ionization - Time of Flight Mass Spectrometry). El grupo Streptococcus anginosus fue el más frecuente (42%) seguido por el grupo Streptococcus mitis (33%). Dentro del grupo S. mitis se excluyó a Streptococcus pneumoniae. El 100% de los aislados fue sensible a ertapenem, linezolid y vancomicina; el 96,9% a cef-triaxona y cefepima. Se encontró un 25,8% de resistencia a penicilina (I+R) fundamentalmente en aislados de grupo S. mitis. La resistencia a tetraciclina fue del 27,2% y solo 2/132 aislados fueron resistentes a levofloxacina. Los valores de CIM de gentamicina oscilaron entre 0,5 y 32 -og/ml. El 17,4% de los aislados presentó resistencia a eritromicina sin diferencia significativa en la distribución de fenotipos M y MLS. Los resultados muestran la importancia de la vigilancia continua de las infecciones producidas por estos microorganismos con el fin de generar aportes para la elección de la terapia antibiótica adecuada.

Members of the viridans group streptococci (VGS) are the cause of local and invasive infections. Due to the severity of these infections and taking into account that reports regarding epidemiological aspects are scarce, the aims of this work were the identification and the study of the antibiotic susceptibility profiles of the isolates recovered from patients that were hospitalized in order to find out about the resistance level and the epidemiology of infections in which VGS are involved. A hundred and thirty two isolates identified as VGS were isolated at Hospital de Clínicas «José de San Martín¼ during the period 2011-2015. The identification was performed by biochemical test and mass spectrometry by Matrix Assisted Laser Desorption Ionization -Time of Flight Mass Spectrometry. Streptococcus anginosus group was prevalent (42%) followed by Streptococcus mitis group (33%). In the latter, isolates of Streptococcus pneumoniae were excluded. All the VGS isolates were susceptible to ertapenem, meropenem, linezolid and vancomycin; 25.8% were resistant (I+R) to penicillin, being prevalent in the S. mitis group. Regarding ceftriaxone and cefepime 96.9% of the isolates were susceptible. Only two isolates were resistant to levofloxacin, 27.2% to tetracycline and it was not found high level resistance to gentamycin (MIC range 0.5-32 µg/ml). Resistance to erythromycin was 17.4% with no significant difference between M and MLS phenotypes. The most active antibiotics were in addition to ceftriaxone and cefepime, vancomycin, ertapenem, meropenem and linezolid. These results highlight the importance of the continuous surveillance of the infections caused by VGS in order to predict a correct antibiotic therapy.

Microbiology and clinical characteristics of viridans group streptococci in patients with cancer

ABSTRACT This study assessed the microbiology, clinical syndromes, and outcomes of oncologic patients with viridans group streptococci isolated from blood cultures between January 1st, 2013 and December 31st, 2016 in a referral hospital in Mexico using the Bruker MALDI Biotyper. Antimicrobial sensitivity was determined using BD Phoenix 100 according to CLSI M100 standards. Clinical information was obtained from medical records and descriptive analysis was performed.Forty-three patients were included, 22 females and 21 males, aged 42 ± 17 years. Twenty (46.5%) patients had hematological cancer and 23 (53.5%) a solid malignancy. The viridans group streptococci isolated were Streptococcus mitis, 20 (46.5%); Streptococcus anginosus, 14 (32.6%); Streptococcus sanguinis, 7 (16.3%); and Streptococcus salivarius, 2 (4.7%). The main risk factors were pyrimidine antagonist chemotherapy in 22 (51.2%) and neutropenia in 19 (44.2%) cases, respectively. Central line associated bloodstream infection was diagnosed in 18 (41.9%) cases. Septic shock occurred in 20.9% of patients, with an overall mortality of 18.6%. Only four S. mitis revealed penicillin-resistance.Our results are similar to those of other series, identifying these bacteria as emerging pathogens with significant morbidity and mortality in oncologic patients. The MALDI-TOF system increased the rate of viridans group streptococci isolation in this population.

Assessment of periodontitis and its role in viridans streptococcal bacteremia and infective endocarditis

Objectives To evaluate the role of periodontitis in viridans group streptococci (VGS) bacteremia and infective endocarditis (IE). Methods A total of 200 subjects including two groups. Group A- 34 subjects undergoing tooth extraction with periodontitis, 46 subjects undergoing tooth extraction without periodontitis and 40 healthy controls. Group B: 40 confirmed cases of IE (17 with and 23 without periodontitis) and 40 healthy controls. Subgingival plaque and blood samples were obtained and processed by standard procedures. Results A total of 53 blood samples (66.25%) yielded positive cultures after tooth extraction. The relationship between the presence of periodontitis and a positive blood culture was significantly higher (p = 0.05) for tooth extraction cases with periodontitis (79.40%) than tooth extraction cases without periodontitis (56.50%). Periodontitis was observed in 42.5% of IE cases. Out of the 40 patients of IE, the blood samples yielded 40 different isolates, majority were viridans streptococci 15 (37.5%) and staphylococci nine (22.5%). No statistically significant difference was observed between the subgingival plaque and blood isolates of periodontitis in both the groups, indicating similarity of biotypes of viridans streptococci isolated from the blood and the subgingival plaque. Similarity was also observed between the antibiogram profiles of viridans streptococci from both the groups. Conclusions Periodontitis enhances viridans streptococcal bacteremia and may be a potential risk factor for IE.

Brain abscess due to Streptococcus oralis in an immunocompetent patient.

A bacteriologically proven case of brain abscess, due to Streptococcus oralis is being reported in a 12‑year‑old girl who is a known case of congenital heart disease. The patient presented with fever, headache and vomiting. Pus cultures yielded S. oralis.

Survey of Antimicrobial Resistance of Pharyngeal alpha-Hemolytic Streptococci among School Children / 대한임상미생물학회지

alpha-hemolytic streptococci (AHS) are common normal oropharyngeal flora that can transfer antibiotic-resistance genes to Streptococcus pneumoniae. Reports on antibiotic resistance in AHS from throats are rare in Korea. A total of 333 healthy school children were subjected to recovery of AHS from the throat, and antibiotic susceptibility tests were screened with the disk diffusion method. The rate of resistance to erythromycin was 22.2%, to clindamycin 12.0%, and to cefotaxime 3.0%. Whereas the resistance rate of S. pneumoniae to erythromycin exceeds 70% in Korea, pharyngeal AHS showed low resistance rates.

Influencia de la concentración inhibitoria mínima de penicilina en la acción sinérgica de su combinación con gentamicina frente a estreptococos del grupo viridans / Influence of penicillin minimal inhibitory concentration in the synergy between penicillin and gentamicin in viridans group streptococci

Los porcentajes de resistencia a penicilina entre los estreptococos del grupo viridans han llegado a niveles superiores al 60% en algunos estudios realizados en la década pasada, y en recientes trabajos se los encontró asociados a un mayor índice de mortalidad en las bacteriemias. Aún no se conoce cuál es el nivel de concentración inhibitoria mínima de penicilina para el cual resulta imposible lograr un efecto sinérgico con algún aminoglucósido. Con este propósito, se estudió la sensibilidad a penicilina de 28 cepas de estreptococos del grupo viridans aisladas de materiales clínicamente significativos en el Hospital de Pediatría "Prof. Dr. Juan P. Garrahan". Se seleccionaron siete aislamientos pertenecientes al grupo mitis con distintas características de sensibilidad, y con ellos se ensayó la curva de muerte frente a penicilina, gentamicina y penicilina más gentamicina, con concentraciones de penicilina por encima y por debajo de su concentración inhibitoria mínima. En ningún caso se observó sinergia cuando la concentración de penicilina fue inferior a la concentración inhibitoria mínima, al menos en este grupo particular de estreptococos que presentaron concentraciones inhibitorias mínimas de gentamicina ³ 16 µg/ml. Se encontró sinergia en cinco de las siete cepas cuando se trabajó con concentraciones de penicilina superiores a la concentración inhibitoria mínima. En las otras dos, se detectaron enzimas modificadoras de aminoglucósidos.

Penicillin resistance rates higher than 60% have been recorded in viridans group streptococci by some authors during the 90's and recently such resistance was associated with higher levels of mortality in bacteremia. The lowest minimal inhibitory concentration of penicillin for which synergy with aminoglycosides is not yet possible is still unknown. In order to try to dilucidate this puzzle, a study on the susceptibility to penicillin of 28 strains of viridans group streptococci isolated from significant samples in the Hospital de Pediatría "Prof. Dr. Juan P. Garrahan" was carried out. Seven mitis group isolates presenting different susceptibility patterns were selected for performing time-killing curves with penicillin, gentamicin, and penicillin plus gentamicin, using higher and lower penicillin concentrations than their minimal inhibitory concentrations. Synergy was not observed when the penicillin concentration was lower than the minimal inhibitory concentration, at least in these strains with minimal inhibitory concentrations of gentamicin ³ 16 µg/ml. When using penicillin in higher concentrations than the minimal inhibitory concentration, synergy was found in five of the seven strains. Aminoglycoside-modifying enzymes were found in the two other streptococci.