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.

Diagnóstico microbiológico de infección por Clostridioides difficile en épocas de COVID-19 en un hospital pediátrico de alta complejidad / Microbiological diagnosis of Clostridioides difficile infection in times of COVID-19 in a high complexity pediatric hospital

Resumen La infección por Clostridioides difficile (ICD) puede variar desde diarrea hasta megacolon tóxico. Los objetivos del trabajo fueron mostrar la variación en el número de casos diagnosticados de ICD en este laboratorio entre 2020, cuando comenzó la pandemia de COVID-19 y 2019 y 2021 y detallar los casos precedidos por la infección de SARS-CoV-2. El presente es un estudio retrospectivo observacional en el que se registraron el número total de muestras procesadas con sospecha de ICD y el de positivas y los antecedentes clínicos de pacientes con ICD hasta dos meses después de su diagnóstico de COVID-19. Durante 2020 se procesaron menos muestras que en 2019 y 2021; sin embargo, el porcentaje de positividad fue de 13,1%, 7,2% y 7,8%, respectivamente. Esto pudo deberse a mejoras en el criterio clínico al momento de seleccionar las muestras con sospecha de ICD.

Abstract Clostridioides difficile infection (CDI) can cause anything from diarrhea to toxic megacolon. The objectives of this study were: to show the variation in the number of diagnosed cases of CDI in this center, comparing 2020, when the COVID-19 pandemic began, with 2019 and 2021 and to detail cases preceded by SARS-CoV-2 infection. This is an observational retrospective study in which the total number of samples processed with suspected CDI were recorded. The positive ones and the clinical history of patients with a diagnosis of CDI up to two months after their diagnosis of SARS-CoV-2 infection were recorded as well. During 2020 a smaller number of samples were processed. However, during this year the percentage of positivity was 13.1% vs. 7,2% and 7.8% during 2019 and 2021, respectively. It is believed that this may have been due to improvements in clinical suspicion and sample selection for CDI diagnosis.

Resumo A infecção por Clostridioides difficile (ICD) pode causar desde diarreia até megacólon tóxico. Os objetivos desta apresentação foram: mostrar a variação do número de casos diagnosticados de ICD neste laboratório, entre 2020 quando começou a pandemia de COVID-19 e 2019 e 2021 e, detalhar os casos precedidos pela infecção por SARS-CoV-2. Esse estudo foi retrospectivo observacional e foram registrados: o número total de amostras processadas com suspeita de ICD e de amostras positivas e os antecedentes clínicos daqueles pacientes com diagnóstico de ICD até dois meses após o diagnóstico de COVID 19. Durante 2020, foram processadas menos amostras do que em 2019 e 2021; no entanto, o percentual de positividade foi de 13,1%, 7,2% e 7,8%, respectivamente. Isso pode ter sido resultado de melhorias no critério clínico na hora de selecionar as amostras com suspeita de ICD.

Genotypes and phylogenetic analysis of adenovirus in children with respiratory infection in Buenos Aires, Argentina (2000-2018).

Human adenoviruses (HAdV) are one of the most frequent causes of respiratory infections around the world, causing mild to severe disease. In Argentina, many studies focused on the association of HAdV respiratory infection with severe disease and fatal outcomes leading to the discovery in 1984 of a genomic variant 7h associated with high fatality. Although several molecular studies reported the presence of at least 4 HAdV species (B, C, D and E) in Argentina, few sequences were available in the databases. In this study, sequences from the hexon gene region were obtained from 141 patients as a first approach to assess the genetic diversity of HAdVs circulating in Buenos Aires, Argentina. Phylogenetic analysis of these sequences and others recovered from public databases confirmed the circulation of the four above-mentioned species represented by 11 genotypes, with predominance in species B and C and shifts in their proportion in the studied period (2000 to 2018). The variants detected in Argentina, for most of the genotypes, were similar to those already described in other countries. However, uncommon lineages belonging to genotypes C2, C5 and E4 were detected, which might indicate the circulation of local variants and will deserve further studies of whole-genome sequences.

Aumento inusual de casos de mielitis en un hospital pediátrico en Argentina / Unusual increase of cases of myelitis in a pediatric hospital in Argentina

Introducción: La asociación entre enterovirus D68 y cuadros de mielitis aguda fláccida ha sido descrita en Estados Unidos, en 2014. Desde ese año, se han reportado casos esporádicamente en Canadá y Europa. Se describe, en este estudio, una serie de casos con mielitis aguda fláccida en el Hospital de Pediatría "Prof. Dr. Juan P. Garrahan" en Buenos Aires, Argentina, en 2016. Métodos: Estudio descriptivo, retrospectivo. Se incluyeron todos los pacientes internados desde el 1/04/2016 al 1/07/2016 con mielitis fláccida aguda con lesiones en la médula espinal que comprometieran la sustancia gris en la resonancia magnética nuclear. Se procesaron, para la búsqueda etiológica, muestras de secreciones nasofaríngeas, hisopados de materia fecal y líquido cefalorraquídeo. Resultados: Se incluyeron 10 pacientes. La mediana de edad fue 4 años (rango de 3 meses a 5 años). Ocho pacientes tuvieron una enfermedad febril autolimitada antes del inicio de los síntomas neurológicos. Los hallazgos neurológicos fueron debilidad fláccida de, al menos, un miembro, cervicoplejia (n= 2) y parálisis facial (n= 2). Todos los pacientes presentaron lesiones longitudinales en la médula espinal, con compromiso de sustancia gris, predominantemente, en el asta anterior. En todos los casos, se realizó una punción lumbar. En 7 pacientes, se observó pleocitosis. En cuatro niños, se identificó enterovirus D68 en secreciones nasofaríngeas y, en uno, se identificó el enterovirusD68 en el líquido cefalorraquídeo. Todos los pacientes persistieron con déficits neurológicos al momento del alta. Conclusiones: Se reporta el primer brote de mielitis aguda fláccida asociada a enterovirusD68 en Argentina. La vigilancia epidemiológica activa permitirá conocer la verdadera incidencia, epidemiología y etiología de esta enfermedad.

Introduction: The association between enterovirus D68 and acute flaccid myelitis was first described in the United States in 2014. Since then, sporadic cases have been reported in Canada and Europe. This study describes a series of cases of acute flaccid myelitis at Hospital de Pediatría "Prof. Dr. Juan P. Garrahan," in Buenos Aires, Argentina, during 2016. Methods: Descriptive, retrospective study. All patients with acute flaccid myelitis and lesions in the spinal cord involving the gray matter, as observed in the magnetic resonance imaging (MRI) scan, hospitalized from 04/01/2016 to 07/01/2016, were included in the study. Samples of nasopharyngeal secretions, fecal swabs and cerebrospinal fluid were collected and processed to look for the causative agent. Results: Ten patients were included. The median age was 4 years old (range from 3 months to 5 years old). Eight patients had a self-limiting febrile condition before the onset of neurological symptoms. Neurological findings were flaccid weakness in, at least, one limb, cervical paralysis (n= 2) and facial paralysis (n= 2). All patients had longitudinal lesions in the spinal cord, with gray matter involvement, mainly in the anterior horn. In all cases, a lumbar puncture (spinal tap) was performed. Pleocytosis was observed in 7 patients. In four children, enterovirus D68 was identified in nasopharyngeal secretions, and in one, it was detected in the cerebrospinal fluid. Neurological deficit persisted in all patients at the time of discharge. Conclusions: The first outbreak of acute flaccid myelitis associated to enterovirus D68 is reported in Argentina. Active epidemiological surveillance will help to determine the true incidence, epidemiology and etiology of this disease.

Unusual increase of cases of myelitis in a pediatric hospital in Argentina. / Aumento inusual de casos de mielitis en un hospital pediátrico en Argentina.

INTRODUCTION: The association between enterovirus D68 and acute flaccid myelitis was first described in the United States in 2014. Since then, sporadic cases have been reported in Canada and Europe. This study describes a series of cases of acute flaccid myelitis at Hospital de Pediatría "Prof. Dr. Juan P. Garrahan," in Buenos Aires, Argentina, during 2016. METHODS: Descriptive, retrospective study. All patients with acute flaccid myelitis and lesions in the spinal cord involving the gray matter, as observed in the magnetic resonance imaging (MRI) scan, hospitalized from 04/01/2016 to 07/01/2016, were included in the study. Samples of nasopharyngeal secretions, fecal swabs and cerebrospinal fluid were collected and processed to look for the causative agent. RESULTS: Ten patients were included. The median age was 4 years old (range from 3 months to 5 years old). Eight patients had a self-limiting febrile condition before the onset of neurological symptoms. Neurological findings were flaccid weakness in, at least, one limb, cervical paralysis (n= 2) and facial paralysis (n= 2). All patients had longitudinal lesions in the spinal cord, with gray matter involvement, mainly in the anterior horn. In all cases, a lumbar puncture (spinal tap) was performed. Pleocytosis was observed in 7 patients. In four children, enterovirus D68 was identified in nasopharyngeal secretions, and in one, it was detected in the cerebrospinal fluid. Neurological deficit persisted in all patients at the time of discharge. CONCLUSIONS: The first outbreak of acute flaccid myelitis associated to enterovirus D68 is reported in Argentina. Active epidemiological surveillance will help to determine the true incidence, epidemiology and etiology of this disease.

INTRODUCCIÓN: La asociación entre enterovirus D68 y cuadros de mielitis aguda fláccida ha sido descrita en Estados Unidos, en 2014. Desde ese año, se han reportado casos esporádicamente en Canadá y Europa. Se describe, en este estudio, una serie de casos con mielitis aguda fláccida en el Hospital de Pediatría "Prof. Dr. Juan P. Garrahan" en Buenos Aires, Argentina, en 2016. MÉTODOS: Estudio descriptivo, retrospectivo. Se incluyeron todos los pacientes internados desde el 1/04/2016 al 1/07/2016 con mielitis fláccida aguda con lesiones en la médula espinal que comprometieran la sustancia gris en la resonancia magnética nuclear. Se procesaron, para la búsqueda etiológica, muestras de secreciones nasofaríngeas, hisopados de materia fecal y líquido cefalorraquídeo. RESULTADOS: Se incluyeron 10 pacientes. La mediana de edad fue 4 años (rango de 3 meses a 5 años). Ocho pacientes tuvieron una enfermedad febril autolimitada antes del inicio de los síntomas neurológicos. Los hallazgos neurológicos fueron debilidad fláccida de, al menos, un miembro, cervicoplejia (n= 2) y parálisis facial (n= 2). Todos los pacientes presentaron lesiones longitudinales en la médula espinal, con compromiso de sustancia gris, predominantemente, en el asta anterior. En todos los casos, se realizó una punción lumbar. En 7 pacientes, se observó pleocitosis. En cuatro niños, se identificó enterovirus D68 en secreciones nasofaríngeas y, en uno, se identificó el enterovirusD68 en el líquido cefalorraquídeo. Todos los pacientes persistieron con déficits neurológicos al momento del alta. CONCLUSIONES: Se reporta el primer brote de mielitis aguda fláccida asociada a enterovirusD68 en Argentina. La vigilancia epidemiológica activa permitirá conocer la verdadera incidencia, epidemiología y etiología de esta enfermedad.

Molecular and serological characterization of species B2 adenovirus strains isolated from children hospitalized with acute respiratory disease in Buenos Aires, Argentina.

BACKGROUND: Between September 2000 and November 2005, approximately 10% of the retrospectively examined human adenovirus (HAdV)-positive pediatric cases of acute respiratory disease (ARD) requiring hospitalization at the Hospital Nacional de Pediatria Juan P. Garrahan in Buenos Aires, Argentina, were found to have a HAdV-B2 infection. OBJECTIVE: To characterize genetically and antigenically the HAdV-B2 virus isolates. STUDY DESIGN: Restriction enzyme analysis (REA), hexon and fiber gene sequencing and virus neutralization assays (VN) were carried out on 8 HAdV-B2 respiratory virus isolates. RESULTS: REA showed that the 8 examined HAdV-B2 virus isolates were HAdV11, belonging to two genomic variants: HAdV11a and a BclI variant of HAdV11c which we designated 11c4. Molecular analysis of the hexon genes showed that both REA variants had a HAdV11-like hexon gene. Confirming previous reports, the 7 HAdV11a virus isolates were found to have HAdV14-like fiber genes and therefore are HAdV H11/F14. The fiber gene of the HAdV11c4 virus isolates most closely resembled that of various strains of HAdV7. In VN assays, the 4 tested HAdV11a strains were serotyped as HAdV11-14. The HAdV11c4 strain was serotyped as HAdV11 but also showed a weak but significant reactivity with antiserum to HAdV7. Compared with the other HAdV-positive cases in our study, infection with HAdV11 caused a similarly severe disease. CONCLUSIONS: Our results provide evidence to the long term world-wide circulation of HAdV H11/F14 as a causative agent of ARD. Combined, our molecular and serology data support the rationale to base the molecular typing and designation of recombinant viruses on the sequences of the hexon and fiber genes.

Clinical features and outcome of 2009 influenza A (H1N1) virus infections in children with malignant diseases: a case-control study.

BACKGROUND: The impact of the novel 2009 influenza A (H1N1) (2009 H1N1) virus in children with malignant diseases under therapy is not well known. OBJECTIVE: To analyze the clinical features and outcome in children with anticancer therapy infected with the 2009 H1N1 virus. PATIENTS AND METHODS: Descriptive, case-control study. Between May and July 2009, 24 cases of 2009 (H1N1) virus infections in children with malignant diseases were registered and 48 control cases of similar patients infected with common influenza A virus (IA) diagnosed between 2006 and 2008 were selected. RESULTS: Median age for cases was 72 months and for controls was 83 months (P ≥ 0.05). Children with IA showed neutropenia more frequently (52% vs. 17%), longer period of time with illness before diagnosis (3 d vs. 1.7 d), higher rate of earlier medical consultation (69% vs. 25%), and more antibiotic therapy courses (54% vs. 4%; P ≤ 0.05) than patients with 2009 H1N1 virus. Children infected with this virus presented hypoxemia more frequently (42% vs. 8%) and higher rates of intensive care unit hospitalizations (29% vs. 2%; P ≤ 0.05). Three children with 2009 H1N1 virus and 1 in the control group died. CONCLUSIONS: Children infected with 2009 H1N1 virus presented more morbidity and mortality than patients infected with seasonal IA virus.

Molecular characterization of an adenovirus 3-16 intertypic recombinant isolated in Argentina from an infant hospitalized with acute respiratory infection.

An intertypic recombinant adenovirus with a serotype 3-like hexon gene and a serotype 16-like fiber (99% identical to that of the prototype strain of human adenovirus 16 [HAdV-16], Ch79) was isolated in Argentina from an infant admitted to the hospital with acute respiratory disease. Consistent with the results of molecular characterization, strain Arg827/04 was designated H3-F16.

Lower respiratory infections by adenovirus in children. Clinical features and risk factors for bronchiolitis obliterans and mortality.

UNLABELLED: Adenovirus (Ad) respiratory infections have a profound impact in Argentina. Severe chronic disease and a high mortality rate are observed in children after acute lower respiratory infections (ALRI) by Ad. METHODS: A retrospective observational study was performed to describe clinical characteristics and to analyze risk factors for bronchiolitis obliterans (BO) and death in 415 children hospitalized with ALRI caused by Ad from March 1988 to May 2005. RESULTS: Mean age of patients was 10.7 months (+/-9.2) Overall 80% of patients were healthy before ALRI. Forty-nine percent recovered, sequelae were observed in 36% and 15% died. Independent risk factors for BO were: >30 days of hospitalization (odds ratio (OR) 27.2, 95% confidence interval (CI) 14.6-50.9), multifocal pneumonia (OR 26.6, 95% CI 5.3-132) and hypercapnia (OR 5.6, 95% CI 3.5-9). Independent risk factors for death in acute stage of disease were: mechanical assistance (OR 121, 95% CI 18.2-814), multifocal pneumonia (OR 102, 95% CI 9.5-31.1), hypercapnia (OR 42.6, 95% CI 10.2-177.1), coagulation disorders (OR 17, 95% CI 8.25-35), neurological symptoms (OR 12.7, 95% CI 3.5-6.6) and co-infection with measles (OR 9.6, 95% CI 2.1-44.2). CONCLUSIONS: High incidence of sequelae and mortality in previously healthy children after Ad infection was observed in a population of children from Argentina.

Gravedad de la infección por virus sincicial respiratorio en pacientes con factores de riesgo y sin ellos / Severity of synctitial respiratory virus infection in patients with risk factors and without them

Objetivo. Analizar diferentes variables de gravedad clínica en niños con factores de riesgo y sin ellos para enfermedad respiratoria por virus sincicial respiratorio en nuestro medio. Población, material y métodos. Estudio retrospectivo de cohorte de historias clínicas de pacientes hospitalizados en el Hospital “Prof. Dr. Juan P. Garrahan”, con diagnóstico de infección respiratoria aguda baja por virus sincicial respiratorio entre 1998 y1999. Se consideraron factores de riesgo: recién nacidos pretérmino ≤ 34 semanas, prematuros ≤ 6 meses al momento de la infección, recién nacidos de término ≤ 45 días, enfermedad pulmonar obstructiva crónica, displasia broncopulmonar, fibrosis quística y cardiopatías congénitas. Se dividió a la población en dos grupos: sin riesgo y con riesgo, y se evaluaron distintas variables. Resultados. Se analizaron 461 pacientes. La edad media fue de 6,96 meses (r igual 0,33 a 23,8 y modo 1 m). La relación M/F fue de 1:0,8. Las formas clínicas de presentación más frecuentes fueron bronquiolitis 72,2 por ciento y neumonía 13,9 por ciento. Los pacientes sin riesgo fueron 57,3 por ciento y con riesgo, 42,7 por ciento. Los pacientes con riesgo tuvieron más días de internación (p igual 0,001), de oxigenoterapia (p igual 0,001) y mayor requerimiento de asistencia respiratoria mecánica y durante más días (p igual 0,001). La mortalidad del grupo fue 1,04 por ciento. Conclusión. Los niños con infección por virus sincicial respiratorio con factores de riesgo requirieron mayor tiempo de internación, de oxigenoterapia y tuvieron mayor probabilidad de requerir asistencia respiratoria mecánica. Estos datos determinan en qué pacientes deberían implementarse medidas preventivas y terapéuticas más precoces para mejorar su evolución y pronóstico