Identificación directa con MALDI-TOF desde el frasco de hemocultivo a partir de subcultivos con incubación corta. Estudio multicéntrico / Direct identification with MALDI-TOF from the blood culture bottle from subcultures with short incubation. Multicenter study / Identificação direta com MALDI-TOF do frasco de hemocultura de subculturas com incubação curta. Estudo multicêntrico

Resumen El objetivo de este trabajo fue evaluar el rendimiento de la identificación realizada con MALDI-TOF a partir de la incubación de 3-5 h de subcultivos de hemocultivos positivos monomicrobianos que se comparó con la obtenida con la incubación de 24 h de los mismos. En dos hospitales se utilizó el sistema Vitek-MS (bioMérieux, Francia) y en uno el sistema Micro- Flex LT (Bruker, Daltonics). A partir de la incubación corta, MALDI-TOF identificó correctamente a 5/5 de las levaduras, a 91,1% (153/168) de las bacterias gram positivas, a 96,7% (119/123) de los bacilos gram negativos y a 93,6% (277/296) del total de cepas. La identificación por medio de MALDI-TOF a partir de una corta incubación de los subcultivos de los hemocultivos en medio sólidos es un método práctico, sencillo y confiable.

Abstract The objective of this work was to evaluate the performance of the identification carried out with MALDI-TOF from the 3-5 h incubation of subcultures of monomicrobial positive blood cultures that was compared with that obtained with the 24 h incubation of the same subcultures. The Vitek-MS system (bioMérieux, France) was used in two hospitals and the Micro-Flex LT system (Bruker, Daltonics) in one. With a short incubation, MALDI-TOF correctly identified 5/5 of the yeasts, 91.1% (153/168) of the gram-positive bacteria, 96.7% (119/123) of the gram-negative bacilli and 93.6% (277/296) of the total strains. Identification by means of MALDI-TOF with a short incubation of subcultures of blood cultures in solid media is a practical, simple and reliable method.

Resumo O objetivo deste trabalho foi avaliar o desempenho da identificação realizada com MALDI-TOF a partir de 3 a 5 h de incubação de subculturas de hemoculturas positivas monomicrobianas que foi comparada com a obtida com a incubação de 24 h das mesmas. O sistema Vitek-MS (bioMérieux, França) foi utilizado em dois hospitais e o sistema Micro-Flex LT (Bruker, Daltonics) em um. A partir da incubação curta, o MALDI-TOF identificou corretamente 5/5 das leveduras, 91,1% (153/168) das bactérias gram positivas, 96,7% (119/123) dos bacilos gram-negativos e 93,6% (277/296) das cepas totais. A identificação por meio de MALDI-TOF a partir de uma incubação curta das subculturas das hemoculturas em meio sólido é um método prático, simples e confiável.

[Optimization in the detection of bacteremia: Integrated use of FilmArray (BCID2) and MALDI-TOF]. / Optimización en la detección de bacteriemias. Uso integrado de FilmArray (BCID2) y MALDI-TOF.

The usefulness of the combined use of MALDI-TOF MS from a subculture with 3-5h of incubation and the BCID2 panel (FilmArray) for the identification of microorganisms from positive blood cultures and its importance in the adjustment of antimicrobial therapy was analyzed. Overall identification with BCID2 was 90.4% (142/157) and with Maldi-TOF MS 83.4% (131/157) (p=0.0858); in 23 polymicrobial episodes (47 strains), the BCID2 panel identified 45 (95.7%) and MALDI-TOF MS 24 (51.1%) (p<0.0000). BCID2 detected the presence of the resistance genes mecA/C (n=16), blaKPC (n=8); blaCTX-M (n=17), blaNDM (n=8), blaOXA-48 (n=1), and vanA/B (n=2). The median time to report a result was 2.0h for BCID2 and 4.0h for MALDI-TOF MS (p<0.0000). Of 124 episodes analyzed, the rapid result of BCID2 led to 82.3% (102/124) therapeutic changes.

Shock séptico en niños con bacteriemia por Staphylococcus aureus de la comunidad en un hospital pediátrico de alta complejidad / Septic shock in children with community acquired Staphylococcus aureus bacteremia in a high complexity pediatric hospital

INTRODUCCIÓN: La información disponible sobre los factores de riesgo para el desarrollo de shock séptico es escasa, especialmente en población pediátrica. OBJETIVO: Describir las características epidemiológicas y clínicas de los niños con bacteriemia adquirida en la comunidad por Staphylococcus aureus y comparar las características de los pacientes con y sin shock séptico. PACIENTES Y MÉTODOS: Estudio de cohorte retrospectivo. Criterios de inclusión: niños entre 30 días y 16 años de edad, internados en el Hospital de Pediatría Juan P. Garrahan entre enero de 2017 y diciembre de 2019 por infecciones adquiridas en la comunidad con desarrollo de S. aureus en hemocultivos. Criterios de exclusión: antecedente de internación dentro de los 3 meses previos al ingreso, vivir en una comunidad cerrada, presencia de catéter de larga permanencia, dispositivos intraventriculares o intraperitoneales. Análisis estadístico: STATA 16. RESULTADOS: Se incluyeron 142 niños. 21 niños (15%) presentaron shock séptico. En el análisis multivariado, se asociaron con shock séptico, la bacteriemia persistente (OR 7,15; IC95% 4,39-23,81; p: 0,001) y el foco secundario de infección (OR 6,72; IC 95% 2,02-22,2; p 0,002). La mortalidad relacionada con la infección fue 3,5% (5 pacientes). CONCLUSIONES: El shock séptico se asoció con la bacteriemia persistente y la presencia de focos secundarios de infección.

BACKGROUND: Available information about risk factors for the development of septic shock is scarce, especially in the pediatric population. AIM: To describe the epidemiological and clinical characteristics of children with community-acquired Staphylococcus aureus bacteremia and to compare the characteristics of children with and without septic shock. METHODS: Retrospective cohort study. Inclusion criteria: Children between 30 days and 16 years old, hospitalized in the Juan P. Garrahan Pediatric Hospital between January 2017 and December 2019 for community-acquired infections with S. aureus isolation in blood cultures. Exclusion criteria: History of hospitalization within 3 months prior to admission, living in a closed community, presence of long-term catheter, intraventricular or intraperitoneal devices. Statistical analysis: STATA 16. RESULTS: 142 children were included. 21 children (15%) experienced septic shock. On multivariate analysis, persistent bacteremia (OR 7.15, 95% CI 4.39-23.81, p: 0.001) and secondary focus of infection (OR 6.72, 95% CI 2.02-22.2, p 0.002) were associated with septic shock. The infection-related mortality rate was 3.5% (5 patients). CONCLUSIONS: Septic shock was associated with persistent bacteremia and the presence of secondary foci of infection.

Pseudomonas putida bacteremia in pediatric patients: A case series study.

INTRODUCTION: Bacteria of the genus Pseudomonas act as opportunistic pathogens. Pseudomonas putida has been considered a pathogen of low virulence and susceptible to multiple antibiotics, but in recent years resistant strains have emerged. The objective of this study is to describe the clinical characteristics, evolution and antibiotic resistance of P. putida bacteremia documented in pediatric hospitalized patients. METHODS: Retrospective cases series. Pediatric patients admitted to the Prof. Dr. Juan P. Garrahan Hospital of Buenos Aires City, Argentina, with isolation in blood cultures of P. putida were included, between August 2015 and August 2020. RESULTS: Sample consisting of 13 patients. Median age: 81 months (IQR 15-163). Ten of the patients were immunocompromised (77%), 11 (85%) had a central venous catheter, 2 (15%) received transfusions prior to the episode of bacteremia, and 6 (46%) had had an invasive procedure within the previous 30 days. Three patients (23%) presented bacteremia secondary to clinical focus and 10 (77%) had central venous catheter-associated bacteremia. All presented fever, 62% (8) evolved with sepsis and 15% (2) with septic shock. Two patients required admission to the intensive care unit (15%), and in 7 (54%) the central venous catheter was removed. None died. The median days of treatment was 14 (IQR 10-14). Resistance to carbapenems was 30%. CONCLUSION: All children had underlying comorbidities, most of them immunocompromised. Catheter-associated infection predominated. The sensitivity to antibiotics was variable. Given the emergence of multi-resistant strains, it is essential to know the local epidemiology.

Carbapenem-resistant Enterobacteriaceae bloodstream infections: A case-control study from a pediatric referral hospital in Argentina.

Background: Antibiotic-resistant gram-negative bloodstream infections (BSI) remain a leading cause morbidity and mortality in pediatric patients with a high impact on the public health system. Data in resource-limited countries, including those in Latin America and the Caribbean region, are scarce. The aim of the study was to identify risk factors for acquiring carbapenem-resistant Enterobacteriaceae (CRE) bacteremia in children and to assess the use of resources. Methods: A retrospective case-control study was conducted to analyze demographic, epidemiological, clinical, microbiological, and outcome data as well as the use of resources between 2014 and 2019. Univariate and logistic regression analysis was performed in order to identify risk factors associated with CRE-BSI. The R software version 4.1.2 was used. Results: A total of 46 cases with CRE-BSI and 92 controls with gram-negative non-CRE-BSI were included. No statistical difference was observed regarding: median age (36 months; IQR, 11.2-117 vs. 48 months, IQR 13-119), male sex (50 vs. 60%), and underlying disease (98 vs. 91%) in cases vs. controls, respectively. The most frequent mechanism of CRE bacteremia were: KPC in 74%, OXA in 15%, and NDM in 6.5%. A total of 54.3% of cases vs. 32.6 % (p = 0.016) of controls were admitted to the pediatric intensive care unit (PICU), and 48 vs. 21% (p = 0.001) required mechanical ventilation. Bacteremia secondary to intra-abdominal infection was observed in 56.5% of cases vs. 35% of controls (p = 0.032). Previous colonization with CRE was detected in 76% of cases vs. 8% of controls. Combination antimicrobial treatment was most frequent in cases vs. control (100 vs. 56.5%). No difference was observed in median length of hospital stay (22 days; IQR, 19-31 in cases vs. 17.5 days; IQR, 10-31 in controls; p = 0.8). Overall case fatality ratio was 13 vs. 5.5%, respectively. The most statistically significant risk factors included previous PICU stay (OR, 4; 95%CI, 2-8), invasive procedures/surgery (OR, 3; 95%CI, 1-7), central venous catheter placement (OR, 6.5; 95%CI, 2-19), urinary catheter placement (OR, 9; 95%CI 4-20), mechanical ventilation (OR, 4; 95%CI, 2-10), liver transplantation (OR, 8; 95%CI, 2-26), meropenem treatment (OR, 8.4; 3.5-22.6) in univariate analysis. The logistic regression model used for multivariate analysis yielded significant differences for previous meropenem treatment (OR, 13; 95%CI, 3-77; p = 0.001), liver transplantation (OR, 13; 95%CI, 2.5-100; p = 0.006), and urinary catheter placement (OR, 9; 95%CI, 1.4-94; p = 0.03). Conclusion: CRE-BSI affects hospitalized children with underlying disease, mainly after liver transplantation, with previous urinary catheter use and receiving broad-spectrum antibiotics, leading to high PICU requirement and mortality. These risk factors will have to be taken into account in our region in order to establish adequate health policies and programs to improve antimicrobial stewardship.

Evaluation of a rapid diagnostic test for the detection of Streptococcus pyogenes in invasive infections / Evaluación de una prueba diagnóstica rápida para la detección de Streptococcus pyogenes en infecciones invasivas

Abstract Invasive Streptococcus pyogenes diseases represent the most severe form of infection produced by this microorganism. Early diagnosis and treatment are important, due to its potential severity. Etiological confirmation of invasive infection is performed by culture, which takes between 18 and 48 h. We tested a rapid immunochromatographic assay directly from clinical samples from normally sterile sites and positive blood culture bottles when pos-itive cocci chains were observed by Gram staining. Eighty samples were analyzed. The rapid test was positive in 35 samples: in 34 of them S. pyogenes was confirmed by culture. The immunochromatographic method showed 97.1% sensitivity and 97.8% specificity. The strept A® immunochromatographic rapid test allows to obtain reliable results in less than 10min and is accessible to any microbiology laboratory. This study demonstrates the potential use of a rapid immunochromatographic method directly from clinical samples and positive blood cultures.

Resumen La enfermedad invasiva por Streptococcus pyogenes representa la forma más grave de infección producida por este microorganismo y requiere un rápido diagnóstico, a fin de instaurar un tratamiento adecuado. La confirmación etiológica de esta infección se realiza por cultivo, lo que puede llevar entre 18 y 48 h. En este estudio ensayamos una prueba inmunocromatográfica rápida directamente de muestras clínicas de sitios normalmente estériles y de botellas de hemocultivos positivos cuando la coloración de Gram evidenció cocos gram positivos en cadena. Se analizaron 80 muestras. La prueba rápida fue positiva en 35 muestras: en 34 de ellas se confirmó la presencia de S. pyogenes por cultivo. La sensibilidad y la especificidad de la prueba fueron del 97,1 y el 97,8%, respectivamente. La prueba inmunocromatográfica rápida monteBIO Strep A® permite obtener resultados confiables en menos de 10 min y es accesible para cualquier laboratorio de microbiología. Este estudio demuestra la utilidad de dicha prueba para ser practicada directamente en muestras clínicas y botellas de hemocultivos positivos.

[Osteo-articular infections by Kingella kingae in children in a highly complex pediatric hospital: epidemiology and associated factors]. / Infecciones osteo-articulares por Kingella kingae en niños en un hospital pediátrico de alta complejidad: epidemiología y factores asociados.

BACKGROUND: The epidemiology of osteoarticular infections (IOA) has changed in recent years. The incidence of Kingella kingae in Latin America is unknown. AIMS: To describe the epidemiology in patients with IOA in a children hospital. To estimate the incidence of IOA due to K. kingae and compare with other etiologies. METHODS: Prospective cohort. Patients older than 1 month hospitalized between March, 1th 2017 and February, 28th 2019 with suspected IOA and diagnostic procedure (biopsy or arthrocentesis) were included. STATA 13 was used. RESULTS: n: 84 patients. The etiology was identified in 58 patients (69.1%). Staphylococus aureus predominated (n: 44; 52.4%) and K. kingae (n: 9; 10.8%). In the period studied, the incidence of IOA by K. kingae was 10.8 cases per 100 hospitalized IOA. In multivariate analysis, age less than 4 years (OR 13.8, 95% CI 5.5-82.7), recent respiratory symptoms (OR 5.7, 95% CI 3.5-31.6, p 0.04) and normalization before the fifth day of C-reactive protein (CRP) (OR 3.38 95% CI 1.8-16.3, p 0.01) were associated with IOA by K. kingae. CONCLUSIONS: In this cohort of children the incidence of K. kingae was 10.8 cases per 100 IOA. Kingella kingae represented the second documented etiology, after S. aureus. Age under 4 years, recent respiratory symptoms and normalization before the fifth day of quantitative CRP were statistically associated with IOA by K. kingae.

Infecciones osteo-articulares por Kingella kingae en niños en un hospital pediátrico de alta complejidad: epidemiología y factores asociados / Osteo-articular infections by Kingella kingae in children in a highly complex pediatric hospital: epidemiology and associated factors

Resumen Introducción: La epidemiología de las infecciones osteo-articulares (IOA) se ha modificado en los últimos años. La incidencia de Kingella kingae en Latinoamérica es desconocida. Objetivo: Describir la epidemiología de los niños con IOA. Estimar la incidencia de IOA causadas por K. kingae y compararlas con otras etiologías. Material y Métodos: Cohorte prospectiva. Se incluyeron pacientes mayores de 1 mes de edad, hospitalizados entre el 1 de marzo de 2017 y 28 de febrero de 2019, con sospecha de IOA y procedimiento diagnóstico (biopsia o artrocentesis). Se utilizó STATA 13. Resultados: n: 84 pacientes. Se identificó la etiología en 58 pacientes (69,1%). Predominaron Staphylococcus aureus (n: 44; 52,4%) y K. kingae (n: 9; 10,8%). En el período estudiado, la incidencia de IOA por K. kingae fue de 10,8 casos cada 100 IOA hospitalizadas. En el análisis multivariado, la edad inferior a 4 años (OR 13,8, IC95% 5,5-82,7), el cuadro respiratorio reciente (OR 5,7, IC95% 3,5-31,6, p 0,04) y la normalización antes del quinto día de la proteína C reactiva (PCR) (OR 3,8 IC95% 1,8- 16,3, p 0,01) se asociaron con las IOA por K. kingae. Conclusiones: En esta cohorte de niños, la incidencia de K.kingae fue de 10,8 casos cada 100 IOA. Kingella kingae representó la segunda etiología documentada, luego de S. aureus. La edad inferior a 4 años, el cuadro respiratorio reciente y la normalización antes del quinto día de la PCR cuantitativa se asociaron estadísticamente con IOA por K. kingae.

Abstract Background: The epidemiology of osteoarticular infections (IOA) has changed in recent years. The incidence of Kingella kingae in Latin America is unknown. Aims: To describe the epidemiology in patients with IOA in a children hospital. To estimate the incidence of IOA due to K. kingae and compare with other etiologies. Methods: Prospective cohort. Patients older than 1 month hospitalized between March, 1th 2017 and February, 28th 2019 with suspected IOA and diagnostic procedure (biopsy or arthrocentesis) were included. STATA 13 was used. Results: n: 84 patients. The etiology was identified in 58 patients (69.1%). Staphylococus aureus predominated (n: 44; 52.4%) and K. kingae (n: 9; 10.8%). In the period studied, the incidence of IOA by K. kingae was 10.8 cases per 100 hospitalized IOA. In multivariate analysis, age less than 4 years (OR 13.8, 95% CI 5.5-82.7), recent respiratory symptoms (OR 5.7, 95% CI 3.5-31.6, p 0.04) and normalization before the fifth day of C-reactive protein (CRP) (OR 3.38 95% CI 1.8-16.3, p 0.01) were associated with IOA by K. kingae. Conclusions: In this cohort of children the incidence of K. kingae was 10.8 cases per 100 IOA. Kingella kingae represented the second documented etiology, after S. aureus. Age under 4 years, recent respiratory symptoms and normalization before the fifth day of quantitative CRP were statistically associated with IOA by K. kingae.

Evaluation of a rapid diagnostic test for the detection of Streptococcus pyogenes in invasive infections.

Invasive Streptococcus pyogenes diseases represent the most severe form of infection produced by this microorganism. Early diagnosis and treatment are important, due to its potential severity. Etiological confirmation of invasive infection is performed by culture, which takes between 18 and 48h. We tested a rapid immunochromatographic assay directly from clinical samples from normally sterile sites and positive blood culture bottles when positive cocci chains were observed by Gram staining. Eighty samples were analyzed. The rapid test was positive in 35 samples: in 34 of them S. pyogenes was confirmed by culture. The immunochromatographic method showed 97.1% sensitivity and 97.8% specificity. The strept A® immunochromatographic rapid test allows to obtain reliable results in less than 10min and is accessible to any microbiology laboratory. This study demonstrates the potential use of a rapid immunochromatographic method directly from clinical samples and positive blood cultures.

Análisis epidemiológico y de factores de riesgo de mortalidad en bacteriemia por Pseudomonas aeruginosa en niños / Epidemiological features and risk factors for mortality in Pseudomonas aeruginosa bacteremia in children

El objetivo fue describir las características epidemiológicas, clínicas, microbiológicas, evolutivas y los factores de riesgo de mortalidad. Estudio de cohorte retrospectivo. Se incluyeron 100 pacientes. Ingresaron con shock séptico 42 (42 %) y 56 (56 %) fueron admitidos a la Unidad de Cuidados Intensivos. La bacteriemia fue primaria en 17 pacientes ( 17 %), asociada a catéter en 15 (15 %) y secundaria en 68 (el 68 %). El foco más frecuente fue mucocutáneo. La resistencia a uno o más grupos de antibióticos fue del 38 %. Fallecieron 31 pacientes (31 %). Los factores de riesgo de mortalidad fueron shock séptico (p < 0,0005), ingreso a la Unidad de Cuidados Intensivos (p < 0,0001), bacteriemia primaria (p < 0,009) o secundaria no asociada a catéter (p < 0,003), presencia de foco mucocutáneo o pulmonar (p < 0,004) y la multirresistencia antibiótica (p < 0,01) o resistencia solo a carbapenemes (p < 0,01).

The objective was to describe the epidemiological, clinical, microbiological, and evolutionary characteristics and the risk factors for mortality. Retrospective, cohort study. A total of 100 patients were included. Of these, 42 (42 %) had septic shock upon admission and 56 (56 %) were admitted to the intensive care unit. Bacteremia was primary in 17 patients (17 %); catheter-related, in 15 (15 %); and secondary, in 68 (68 %). The most common source of infection was the skin and mucous membrane. Resistance to one or more antibiotic groups was 38 %. Thirty-one patients died (31 %). Risk factors for mortality were septic shock (p < 0.0005), admission to the intensive care unit (p < 0.0001), primary bacteremia (p < 0.009) or secondary, non-catheter-related bacteremia (p < 0.003), presence of mucocutaneous or pulmonary source of infection (p < 0.004), and multidrug resistance (p < 0.01) or resistance to carbapenems (p < 0.01).

Epidemiological features and risk factors for mortality in Pseudomonas aeruginosa bacteremia in children. / Análisis epidemiológico y de factores de riesgo de mortalidad en bacteriemia porPseudomonas aeruginosa en niños.

The objective was to describe the epidemiological, clinical, microbiological, and evolutionary characteristics and the risk factors for mortality. Retrospective, cohort study. A total of 100 patients were included. Of these, 42 (42 %) had septic shock upon admission and 56 (56 %) were admitted to the intensive care unit. Bacteremia was primary in 17 patients (17 %); catheter-related, in 15 (15 %); and secondary, in 68 (68 %). The most common source of infection was the skin and mucous membrane. Resistance to one or more antibiotic groups was 38 %. Thirty-one patients died (31 %). Risk factors for mortality were septic shock (p < 0.0005), admission to the intensive care unit (p < 0.0001), primary bacteremia (p < 0.009) or secondary, non-catheter-related bacteremia (p < 0.003), presence of mucocutaneous or pulmonary source of infection (p < 0.004), and multidrug resistance (p < 0.01) or resistance to carbapenems (p < 0.01).

El objetivo fue describir las características epidemiológicas, clínicas, microbiológicas, evolutivas y los factores de riesgo de mortalidad. Estudio de cohorte retrospectivo. Se incluyeron 100 pacientes. Ingresaron con shock séptico 42 (42 %) y 56 (56 %) fueron admitidos a la Unidad de Cuidados Intensivos. La bacteriemia fue primaria en 17 pacientes ( 17 %), asociada a catéter en 15 (15 %) y secundaria en 68 (el 68 %). El foco más frecuente fue mucocutáneo. La resistencia a uno o más grupos de antibióticos fue del 38 %. Fallecieron 31 pacientes (31 %). Los factores de riesgo de mortalidad fueron shock séptico (p < 0,0005), ingreso a la Unidad de Cuidados Intensivos (p < 0,0001), bacteriemia primaria (p < 0,009) o secundaria no asociada a catéter (p < 0,003), presencia de foco mucocutáneo o pulmonar (p < 0,004) y la multirresistencia antibiótica (p < 0,01) o resistencia solo a carbapenemes (p < 0,01).

Infecciones por bacilos Gram-negativos multirresistentes en neonatología / Multidrug resistant Gram-negative infections in neonatology

Introducción. Las infecciones por bacilos Gram-negativos multirresistentes (BGN-MR) constituyen un problema creciente en las unidades de cuidado intensivo neonatal. El objetivo del estudio fue conocer las características epidemiológicas, clínicas, microbiológicas, evolutivas y los factores de riesgo de infección por BGN-MR resistentes a carbapenemes en el Servicio de Neonatología de un hospital de alta complejidad. Población y método. Se realizó un estudio de cohorte retrospectivo en dicho Servicio, donde se incluyeron los pacientes con infección documentada por BGN-MR del 24/4/2013 al 29/4/2015. Resultados. Se incluyeron 21 pacientes. La mediana de edad gestacional y peso de nacimiento fue 35 semanas y 2070 gramos, respectivamente. Dieciocho pacientes (86 %) tuvieron hemocultivos positivos y el aislamiento microbiológico más frecuente fue Acinetobacter baumannii (17 pacientes, 81 %), seguido por Klebsiella pneumoniae productora de carbapenemasa (3 pacientes, 14 %) y Enterobacter cloacae (1 paciente, 5 %). La mediana de edad al momento del diagnóstico fue de 28 días y todos tenían factores de riesgo para la infección, como cirugía, asistencia respiratoria mecánica, nutrición parenteral, catéter central y antibióticos. El tratamiento antibiótico definitivo fue colistina en todos los casos, combinado en el 84 %. Cinco pacientes (24 %) fallecieron por la infección. La prematurez y el peso < 2000 g fueron factores de riesgo estadísticamente significativos asociados a la mortalidad (p = 0,03 y 0,01, respectivamente). Conclusión. Las infecciones por BGN-MR se presentaron en pacientes con factores predisponentes. Acinetobacter baumannii fue el primer agente etiológico. La mortalidad fue elevada y relacionada con prematurez y bajo peso al nacer.

Introduction. Multidrug resistant Gramnegative (MDRGN) infections are an increasing problem in neonatal intensive care units. The objective of this study was to establish the epidemiological, clinical, microbiological, and evolutionary characteristics of carbapenem-resistant MDRGN infections and the risk factors for them at the Division of Neonatology of a tertiary care hospital. Population and method. A retrospective cohort study was done in this Division in patients with a documented MDRGN infection between 4/24/2013 and 4/29/2015. Results. Twenty-one patients were included. Their median gestational age and birth weight were 35 weeks and 2070 g, respectively. Eighteen patients (86 %) had a positive blood culture; the most commonly isolated microorganism was Acinetobacter baumannii (17 patients, 81 %), followed by carbapenemase-producing Klebsiella pneumoniae (3 patients, 14 %) and Enterobacter cloacae (1 patient, 5 %). The median age at diagnosis was 28 days and all patients had risk factors for infection, including surgery, assisted mechanical ventilation, parenteral nutrition, central venous line, and antibiotics. The definite antibiotic therapy included colistin in all cases; in combination, in 84 %. Five patients (24 %) died due to the infection. Prematurity and a birth weight < 2000 g were statistically significant risk factors associated with mortality (p = 0.03 and 0.01, respectively). Conclusion. MDRGN infections were observed in patients with predisposing factors. Acinetobacter baumannii was the main etiologic agent. Mortality was high and related to prematurity and a low birth weight.

Multidrug resistant Gram-negative infections in neonatology. / Infecciones por bacilos Gram-negativos multirresistentes en neonatología.

INTRODUCTION: Multidrug resistant Gramnegative (MDRGN) infections are an increasing problem in neonatal intensive care units. The objective of this study was to establish the epidemiological, clinical, microbiological, and evolutionary characteristics of carbapenem-resistant MDRGN infections and the risk factors for them at the Division of Neonatology of a tertiary care hospital. POPULATION AND METHOD: A retrospective cohort study was done in this Division in patients with a documented MDRGN infection between 4/24/2013 and 4/29/2015. RESULTS: Twenty-one patients were included. Their median gestational age and birth weight were 35 weeks and 2070 g, respectively. Eighteen patients (86 %) had a positive blood culture; the most commonly isolated microorganism was Acinetobacter baumannii (17 patients, 81 %), followed by carbapenemase-producing Klebsiella pneumoniae (3 patients, 14 %) and Enterobacter cloacae (1 patient, 5 %).The median age at diagnosis was 28 days and all patients had risk factors for infection, including surgery, assisted mechanical ventilation, parenteral nutrition, central venous line, and antibiotics. The definite antibiotic therapy included colistin in all cases; in combination, in 84 %. Five patients (24 %) died due to the infection. Prematurity and a birth weight < 2000 g were statistically significant risk factors associated with mortality (p = 0.03 and 0.01, respectively). CONCLUSION: MDRGN infections were observed in patients with predisposing factors. Acinetobacter baumannii was the main etiologic agent. Mortality was high and related to prematurity and a low birth weight.

Introducción. Las infecciones por bacilos Gram-negativos multirresistentes (BGN-MR) constituyen un problema creciente en las unidades de cuidado intensivo neonatal. El objetivo del estudio fue conocer las características epidemiológicas, clínicas, microbiológicas, evolutivas y los factores de riesgo de infección por BGN-MR resistentes a carbapenemes en el Servicio de Neonatología de un hospital de alta complejidad. Población y método. Se realizó un estudio de cohorte retrospectivo en dicho Servicio, donde se incluyeron los pacientes con infección documentada por BGN-MR del 24/4/2013 al 29/4/2015. Resultados. Se incluyeron 21 pacientes. La mediana de edad gestacional y peso de nacimiento fue 35 semanas y 2070 gramos, respectivamente. Dieciocho pacientes (86 %) tuvieron hemocultivos positivos y el aislamiento microbiológico más frecuente fue Acinetobacter baumannii (17 pacientes, 81 %), seguido por Klebsiella pneumoniae productora de carbapenemasa (3 pacientes, 14 %) y Enterobacter cloacae (1 paciente, 5 %). La mediana de edad al momento del diagnóstico fue de 28 días y todos tenían factores de riesgo para la infección, como cirugía, asistencia respiratoria mecánica, nutrición parenteral, catéter central y antibióticos. El tratamiento antibiótico definitivo fue colistina en todos los casos, combinado en el 84 %. Cinco pacientes (24 %) fallecieron por la infección. La prematurez y el peso < 2000 g fueron factores de riesgo estadísticamente significativos asociados a la mortalidad (p = 0,03 y 0,01, respectivamente). Conclusión. Las infecciones por BGN-MR se presentaron en pacientes con factores predisponentes. Acinetobacter baumannii fue el primer agente etiológico. La mortalidad fue elevada y relacionada con prematurez y bajo peso al nacer.

[Epidemiology and risk factors for prolonged hospital length of stay in children with leukemia and bacteremia. Cohort study]. / Epidemiología y factores de riesgo de internación prolongada en niños con leucemia y bacteriemia. Estudio de cohorte.

INTRODUCTION: Bacteremia is a frequent complication in children with cancer, which is associated with greater severity, prolonged hospitalization and mortality. Prolonged hospitalization conditions greater morbidity and risk of acquisition of intranosocomial infections. AIM: To describe risk factors for prolonged hospital length of stay in children with leukemia and bacteremia. METHODS: Cohort study. Episodes of bacteremia in patients with leukemia at Garrahan Hospital from 1/1/2015 to 31/12/2016 were reviewed. We compared data from patients with a LOS of 14 days or more with those admitted for less than 14 days. Bivariate and logistic regression analysis was performed. We used Stata 13 statistical package. RESULTS: n = 121. Median age 59 months.81 patients (67%) had a diagnosis of acute lymphoblastic leukemia, followed by acute myeloid leukemia in 40 (33%). 96 patients (79%) had a central venous catheter (CVC), 94 patients (78%) were neutropenic. Blood cultures were positive for Enterobacteriaceae in 55 cases (45%), coagulase-negative staphylococci in 28 cases (23%), Group viridans Streptococcus in 19 (16%), Pseudomonas aeruginosa in 8 (7%). (9%). By the multivariate analysis, three factors remained significantly associated with length of stay of more than 14 days: CVC associated bacteremia (OR 21,73; CI95% 1.2-43.2; p 0.04), severe neutropenia (OR 1.75; CI95% 1.82-1.28; p 0.03) and coinfection (OR 27.4; CI95% 2.8-260.8; p 0.004). CONCLUSION: CVC associated bacteremia, severe neutropenia and viral coinfection were associated with hospital LOS of more than 14 days.

Infecciones osteoarticulares en un hospital pediátrico de alta complejidad: epidemiología y características clínicas asociadas con bacteriemia / Osteoarticular infections in a tertiary care children's hospital: Epidemiology and clinical characteristics in association with bacteremia

Introducción. Las infecciones osteoarticulares son una importante causa de morbilidad y pueden presentar bacteriemia. La epidemiología de estas infecciones se ha modificado en los últimos años. Objetivos. Describir las características epidemiológicas, clínicas y evolutivas de los niños con infecciones osteoarticulares y comparar los pacientes con bacteriemia con los que no la presentaron. Población y métodos. Cohorte retrospectiva. Se incluyeron pacientes menores de 18 años, admitidos en el Hospital Juan P. Garrahan entre el 1/1/2016 y el 31/12/2016 con sospecha de infecciones osteoarticulares en quienes se hubiese realizado artrocentesis y/o biopsia articular. Se excluyeron niños con patología previa. Se compararon las características clínicas y de laboratorio según tuvieran bacteriemia o no. Se utilizó Stata 10. Resultados. N: 62. La mediana de edad fue 59.5 meses (rango intercuartilo -RIC- 24-84). Presentaron fiebre 44 pacientes (70%). Predominaron las artritis (54 pacientes, 87%). Se identificó un agente etiológico en 29 pacientes (47%). Predominó Staphylococcus aureus (n: 20, 32%). Tuvieron bacteriemia 15 de ellos (24%). Recibieron clindamicina como tratamiento empírico 56 pacientes (90%). La mediana de tratamiento endovenoso fue 7 días (RIC 5-11) y de internación, 7 días (RIC 4-12). Los pacientes con bacteriemia tuvieron menor edad (26 meses vs. 60, p < 0,05), mayor valor de proteína C reactiva inicial (101 vs. 33 U/L, p < 0,05), menor valor de hemoglobina al ingresar (10,8 g/dl vs. 12.5 g/dl, p 0,04) y mayor frecuencia de fiebre (100% vs. 57%, p < 0,05). Conclusiones. Predominó Staphylococcus aureus. Los niños con bacteriemia tuvieron menor edad, mayor valor de proteína C reactiva, menos hemoglobina al ingresar y, más frecuentemente, fiebre.

Introduction. Osteoarticular infections are an important cause of morbidity and may present with bacteremia. The epidemiology has changed in recent years. Objectives. To describe the epidemiological, clinical, and evolutionary characteristics of children with osteoarticular infections and compare patients with and without bacteremia. Population and methods. Retrospective cohort. Patients younger than 18 years admitted between January 1st, 2016 and December 31st, 2016 suspected of osteoarticular infections who had undergone an arthrocentesis and/or joint biopsy were included. Clinical and laboratory characteristics were compared between patients with and without bacteremia. The Stata 10 software was used.Results. N: 62. Patients' median age was 59.5 months (interquartile range [IQR]: 24-84). Fever developed in 44 patients (70%). Arthritis predominated (54 patients, 87%). An etiologic agent was identified in 29 patients (47%). Staphylococcus aureus was prevalent (n: 20, 32%). Among these, 15 developed bacteremia (24%). Clindamycin was administered to 56 patients (90%) as empirical therapy. The median intravenous treatment duration was 7 days (IQR: 5-11) and the median length of stay, 7 days (IQR: 4-12). Patients with bacteremia were younger (26 months versus 60 months, p < 0.05), had a higher baseline C-reactive protein level (101 U/L versus 33 U/L, p < 0.05), a lower hemoglobin level at the time of admission (10.8 g/dL versus 12.5 g/dL, p = 0.04), and a higher frequency of fever (100% versus 57%, p < 0.05).Conclusions. Staphylococcus aureus was prevalent. Children with bacteremia were younger, had a higher C-reactive protein level, a lower hemoglobin level at the time of admission, and 100% presented fever

Osteoarticular infections in a tertiary care children's hospital: Epidemiology and clinical characteristics in association with bacteremia. / Infecciones osteoarticulares en un hospital pediátrico de alta complejidad: epidemiología y características clínicas asociadas con bacteriemia.

INTRODUCTION: Osteoarticular infections are an important cause of morbidity and may present with bacteremia. The epidemiology has changed in recent years. OBJECTIVES: To describe the epidemiological, clinical, and evolutionary characteristics of children with osteoarticular infections and compare patients with and without bacteremia. POPULATION AND METHODS: Retrospective cohort. Patients younger than 18 years admitted between January 1st, 2016 and December 31st, 2016 suspected of osteoarticular infections who had undergone an arthrocentesis and/or joint biopsy were included. Clinical and laboratory characteristics were compared between patients with and without bacteremia. The Stata 10 software was used. RESULTS: N: 62. Patients' median age was 59.5 months (interquartile range [IQR]: 24-84). Fever developed in 44 patients (70%). Arthritis predominated (54 patients, 87%). An etiologic agent was identified in 29 patients (47%). Staphylococcus aureus was prevalent (n: 20, 32%). Among these, 15 developed bacteremia (24%). Clindamycin was administered to 56 patients (90%) as empirical therapy. The median intravenous treatment duration was 7 days (IQR: 5-11) and the median length of stay, 7 days (IQR: 4-12). Patients with bacteremia were younger (26 months versus 60 months, p < 0.05), had a higher baseline C-reactive protein level (101 U/L versus 33 U/L, p < 0.05), a lower hemoglobin level at the time of admission (10.8 g/dL versus 12.5 g/dL, p = 0.04), and a higher frequency of fever (100% versus 57%, p < 0.05). CONCLUSIONS: Staphylococcus aureus was prevalent. Children with bacteremia were younger, had a higher C-reactive protein level, a lower hemoglobin level at the time of admission, and 100% presented fever.

INTRODUCCIÓN: Las infecciones osteoarticulares son una importante causa de morbilidad y pueden presentar bacteriemia. La epidemiología de estas infecciones se ha modificado en los últimos años. OBJETIVOS: Describir las características epidemiológicas, clínicas y evolutivas de los niños con infecciones osteoarticulares y comparar los pacientes con bacteriemia con los que no la presentaron. POBLACIÓN Y MÉTODOS: Cohorte retrospectiva. Se incluyeron pacientes menores de 18 años, admitidos en el Hospital Juan P. Garrahan entre el 1/1/2016 y el 31/12/2016 con sospecha de infecciones osteoarticulares en quienes se hubiese realizado artrocentesis y/o biopsia articular. Se excluyeron niños con patología previa. Se compararon las características clínicas y de laboratorio según tuvieran bacteriemia o no. Se utilizó Stata 10. RESULTADOS: N: 62. La mediana de edad fue 59.5 meses (rango intercuartilo -RIC- 24-84). Presentaron fiebre 44 pacientes (70%). Predominaron las artritis (54 pacientes, 87%). Se identificó un agente etiológico en 29 pacientes (47%). Predominó Staphylococcus aureus (n: 20, 32%). Tuvieron bacteriemia 15 de ellos (24%). Recibieron clindamicina como tratamiento empírico 56 pacientes (90%). La mediana de tratamiento endovenoso fue 7 días (RIC 5-11) y de internación, 7 días (RIC 4-12). Los pacientes con bacteriemia tuvieron menor edad (26 meses vs. 60, p < 0,05), mayor valor de proteína C reactiva inicial (101 vs. 33 U/L, p < 0,05), menor valor de hemoglobina al ingresar (10,8 g/dl vs. 12.5 g/dl, p 0,04) y mayor frecuencia de fiebre (100% vs. 57%, p < 0,05). CONCLUSIONES: Predominó Staphylococcus aureus. Los niños con bacteriemia tuvieron menor edad, mayor valor de proteína C reactiva, menos hemoglobina al ingresar y, más frecuentemente, fiebre.

Risk factors for the appearance of secondary foci of infection in children with community-acquired Staphylococcus aureus bacteraemia. Cohort study 2010-2016. / Factores de riesgo de focos secundarios de infección en niños con bacteriemia por Staphylococcus aureus adquirida en la comunidad. Estudio de cohorte 2010-2016.

INTRODUCTION: Community-acquired Staphylococcus aureus (SA) bacteraemia is a common cause of hospitalisation in children. The occurrence of secondary foci (SF) of SA infection is associated with higher morbidity and mortality. OBJECTIVES: To identify risk factors for SF of infection in children with community-acquired SA bacteraemia. MATERIAL AND METHODS: Prospective cohort. All children aged from 30 days to 16 years admitted to a paediatric referral hospital between January 2010 and December 2016 for community-acquired infections, with SA isolated in blood cultures, were included. Microbiological, demographic and clinical characteristics were compared, with or without SF infection after 72hours of hospitalisation. RESULTS: A total of 283 patients were included, 65% male (n=184), with a median age of 60 months (IQR: 30-132). Seventeen per cent (n=48) had at least one underlying disease and 97% (n=275) had some clinical focus of infection, the most common being: osteoarticular 55% (n=156) and soft tissue abscesses 27% (n=79). A total of 65% (n=185) were resistant to methicillin. A SF of infection was found in 16% of patients (n=44). The SF identified were pneumonia 73% (n=32), osteoarticular 11% (n=5), soft tissue 11% (n=5) and central nervous system 5% (n=2). In the multivariate analysis, the persistence of positive blood cultures after the fifth day (OR: 2.40, 95%CI: 1.07-5.37, P<0.001) and sepsis (OR: 17.23, 95%CI 5.21-56.9, P<0.001) were predictors of SF. There was no association with methicillin sensitivity. CONCLUSIONS: In this cohort, methicillin-resistant SA infections predominated. The occurrence of SF of infection was associated with the persistence of bacteraemia after the fifth day and sepsis on admission.

Epidemiología y factores de riesgo de internación prolongada en niños con leucemia y bacteriemia: estudio de cohorte / Epidemiology and risk factors for prolonged hospital length of stay in children with leukemia and bacteremia: cohort study

Resumen Introducción: La bacteriemia constituye una complicacion frecuente en los niños con cáncer, que se asocia a mayor gravedad, internación prolongada y mortalidad. La internación prolongada condiciona mayor morbilidad y riesgo de adquisición de infecciones intranosocomiales. Objetivo: Analizar factores de riesgo de internación prolongada en niños con leucemia y bacteriemia. Pacientes y Métodos: Cohorte retrospectiva. Se incluyeron niños con leucemia internados en el Hospital Garrahan entre 1/1/2015 y 31/12/2016 con bacteriemia. Se compararon características de pacientes con internaciones menores o mayores a 14 días. Se realizó un análisis bivariado y modelo de regresión logística. Se utilizó Stata 13. Resultados: n = 121. Mediana de edad 59 meses. Tenían leucemia linfoblastica 81 pacientes (67%) y leucemia mieloblástica 40 (33%). Tenían catéter venoso central (CVC) 96 de los niños (79%), neutropenia 94 (78%), neutropenia menor a 100 neutrófilos 79 (65%). La identificación en hemocultivos fue: 55 casos (45%) enterobacterias, 28 (23%) Staphylococcus coagulasa negativa, Streptococcus spp grupo viridans 19 (16%), Pseudomonas aeruginosa 8 (7%). Huo co-infección viral en 14 pacientes (12%).Tuvieron menos de 14 días de internación 71 pacientes (59%) y mayor período 50 (41%). En el análisis multivariado la bacteriemia asociada a CVC (OR 21,73; IC95% 1,2-43,20; p 0,04), neutropenia profunda al ingreso (OR 1,75; IC95% 1,82-1,28; p 0,03) y co-infección viral (OR 27,42; IC95% 2,88-260,83; p 0,004) fueron factores de riesgo de internación > 14 días. Conclusiones: La bacteriemia asociada a CVC, la neutropenia profunda al ingreso y la co-infección se asociaron con una internación igual o mayor a 14 días.

ABSTRACT Introduction: Bacteremia is a frequent complication in children with cancer, which is associated with greater severity, prolonged hospitalization and mortality. Prolonged hospitalization conditions greater morbidity and risk of acquisition of intranosocomial infections. Aim: To describe risk factors for prolonged hospital length of stay in children with leukemia and bacteremia. Methods: Cohort study. Episodes of bacteremia in patients with leukemia at Garrahan Hospital from 1/1/2015 to 31/12/2016 were reviewed. We compared data from patients with a LOS of 14 days or more with those admitted for less than 14 days. Bivariate and logistic regression analysis was performed. We used Stata 13 statistical package. Results: n = 121. Median age 59 months.81 patients (67%) had a diagnosis of acute lymphoblastic leukemia, followed by acute myeloid leukemia in 40 (33%). 96 patients (79%) had a central venous catheter (CVC), 94 patients (78%) were neutropenic. Blood cultures were positive for Enterobacteriaceae in 55 cases (45%), coagulase-negative staphylococci in 28 cases (23%), Group viridans Streptococcus in 19 (16%), Pseudomonas aeruginosa in 8 (7%). (9%). By the multivariate analysis, three factors remained significantly associated with length of stay of more than 14 days: CVC associated bacteremia (OR 21,73; CI95% 1.2-43.2; p 0.04), severe neutropenia (OR 1.75; CI95% 1.82-1.28; p 0.03) and coinfection (OR 27.4; CI95% 2.8-260.8; p 0.004). Conclusion: CVC associated bacteremia, severe neutropenia and viral coinfection were associated with hospital LOS of more than 14 days.

Characterization of Streptococcus pneumoniae invasive serotype 19A isolates from Argentina (1993-2014).

The aim of this study was to characterize Streptococcus pneumoniae serotype 19A isolates causing invasive pneumococcal disease in children, collected in Argentina between 1993 and 2014. A total of 176 isolates serotype 19A were analyzed. There was an increase in the proportion of serotype 19A isolates from 3% in 1993 to 6% in 2011, prior to the introduction of PCV13 in 2012, and from 2012 to 2014 its proportion gradually decreased. Penicillin resistance among serotype 19A isolates throughout the study period was 65.9%, but a significant increase was observed from 0% in 1993 to 87.5% in 2014. Genetic relationship of the isolates was determined by PFGE and selected strains were studied by MLST. Most of the isolates belonged to two clonal types: A (54.5%) and B (11.4%). Isolates of clonal type A were ST1131, a single locus variant of ST172 and accounted for 54% of the total collection. They were detected for the first time in our country in 1997 and most of them (93%) were penicillin non susceptible. Isolates of clonal type B were ST8121, a single locus variant of ST199, and were mainly susceptible to penicillin. These two clonal types are still in circulation and appear to be responsible for the dissemination of S. pneumoniae serotype 19A invasive isolates in our country.

Bacteriemia por Staphylococcus aureus adquirido en la comunidad en niños: estudio de cohorte 2010-2014 / Community-acquired Staphylococcus aureus bacteremia in children: a cohort study for 2010-2014

Introducción. Las infecciones por Staphylococcus aureus meticilino resistente adquirido en la comunidad son un problema grave y frecuente en pediatría. Objetivo. Describir la resistencia a los antibióticos enlas infecciones bacteriémicas por Staphylococcus aureus (SA) de la comunidad. Comparar las características de las infecciones bacteriémicas por SA según la resistencia a la meticilina. Material y métodos. Cohorte prospectiva entre enero de 2010 y diciembre de 2014. Criterios de inclusión: niños de entre 30 días y 16 años de edad hospitalizados en el Hospital de Pediatría J. P. Garrahan por infecciones adquiridas en la comunidad, con desarrollo de SA en hemocultivos. Criterios de exclusión: antecedente de internación reciente, asistencia a un centro relacionado con los cuidados de la salud, vivir en una comunidad cerrada o catéter venoso. Se compararon características microbiológicas, demográficas y clínicas según la sensibilidad a la meticilina. Análisis estadístico: Stata10. Resultados. Se incluyeron 208 niños; varones: 141 (68%). La mediana de edad fue 60 meses (rango intercuartilo 29-130). Tenían enfermedad de base 34 pacientes (16%). En 136 niños (65%), se identificó Staphylococcus aureus meticilino resistente. La resistencia a la clindamicina fue 9%. Se encontraron diferencias estadísticas significativas en la frecuencia de enfermedad subyacente, bacteriemia persistente, sepsis al momento del ingreso, foco secundario de infección, ingreso a unidades de cuidados intensivos y necesidad de cirugía. Fallecieron 12 pacientes (6%); todos tuvieron identificación de Staphylococcus aureus meticilino resistente adquirido en la comunidad. Conclusiones. En la cohorte estudiada, predominó el Staphylococcus aureus meticilino resistente. La resistencia a la clindamicina fue del 9%. Las infecciones por Staphylococcus aureus meticilino resistente adquirido en la comunidad predominaron en niños sanos. En los pacientes con Staphylococcus aureus meticilino resistente, fue más frecuente la bacteriemia persistente, el ingreso a unidades de cuidados intensivos y la cirugía.

Introduction. Community-acquired methicillin-resistant Staphylococcus aureus infections are a common, serious problem in pediatrics.Objective. To describe antibiotic resistance in community-acquired Staphylococcus aureus (SA) bacteremias. To compare the characteristics of SA bacteremias in terms of methicillin resistance.Material and methods. Prospective cohort enrolled between January 2010 and December 2014. Inclusion criteria: infants and children between 30 days old and 16 years old hospitalized at the Hospital de Pediatría J. P. Garrahan due to community-acquired infections with SA growth identification in blood cultures. Exclusion criteria: having a history of recent hospitalization, attending a health care facility, living in a closed community, or having a venous catheter. Microbiological, demographic, and clinical characteristics were compared in terms of methicillin susceptibility. Statistical analysis: Stata10.Results. A total of 208 children were included; boys: 141 (68%). Their median age was 60 months old (interquartile range: 29-130). Thirty-four patients (16%) had an underlying disease. Methicillin-resistant Staphylococcus aureus was identified in 136 children (65%). The rate of resistance to clindamycin was 9%. Significant statistical differences were observed in the rate of underlying disease, persistent bacteremia, sepsis at the time of admission, secondary source of infection, admission to the intensive care unit, and surgery requirement. Twelve patients (6%) died; community-acquired methicillin-resistant Staphylococcus aureus was identified in all of them.Conclusions. In the studied cohort, methicillin-resistant Staphylococcus aureus was predominant. The rate of resistance to clindamycin was 9%. Community-acquired methicillin-resistant Staphylococcus aureus infections prevailed among healthy children. Among patients with methicillin-resistant Staphylococcus aureusinfections there was a higher rate of persistent bacteremia, admission to the ICU and surgery