Hemocultivos en urgencias pediátricas. Guía práctica de recomendaciones: indicaciones, técnica de extracción, procesamiento e interpretación / Blood cultures in the paediatric emergency department. Guidelines and recommendations on their indications, collection, processing and interpretation

El hemocultivo (HC) es el método diagnóstico de elección ante la sospecha de bacteriemia, siendo una de las técnicas microbiológicas más solicitadas en pediatría. Diversos cambios han acontecido en los últimos años como la introducción de nuevas vacunas, el aumento creciente de pacientes portadores de catéteres vasculares centrales, o la irrupción de los sistemas automáticos de procesamiento de los HC. Dichos cambios han propiciado la revisión y la actualización de los distintos aspectos relacionados con esta técnica con el fin de optimizar su uso. Se presenta una guía práctica sobre recomendaciones acerca de la extracción, el procesamiento y la interpretación de los HC elaborada por la Sociedad Española de Urgencias de Pediatría y la Sociedad Española de Infectología Pediátrica. Tras revisar la información científica disponible, se presentan una serie de recomendaciones para cada uno de los siguientes apartados: indicaciones en Urgencias, técnica de extracción, transporte y procesamiento de la muestra, factores a tener en cuenta en situaciones especiales (indicaciones e interpretación de resultados en el paciente inmunodeprimido y/o portador de catéter vascular central, indicaciones de HC para anaerobios), diferenciación entre bacteriemia y contaminación ante un HC con crecimiento bacteriano y actitud a tomar ante un HC positivo en el paciente con fiebre sin foco

Blood culture (BC) is the gold standard when a bacteraemia is suspected, and is one of the most requested microbiological tests in paediatrics. Some changes have occurred in recent years: the introduction of new vaccines, the increasing number of patients with central vascular catheters, as well as the introduction of continuous monitoring BC systems. These changes have led to the review and update of different factors related to this technique in order to optimise its use. A practice guideline is presented with recommendations on BC, established by the Spanish Society of Paediatric Emergency Care and the Spanish Society for Paediatric Infectious Diseases. After reviewing the available scientific evidence, several recommendations for each of the following aspects are presented: BC indications in the Emergency Department, how to obtain, transport and process cultures, special situations (indications and interpretation of results in immunosuppressed patients and/or central vascular catheter carriers, indications for anaerobic BC), differentiation between bacteraemia and contamination when a BC shows bacterial growth and actions to take with a positive BC in patients with fever of unknown origin

[Blood cultures in the paediatric emergency department. Guidelines and recommendations on their indications, collection, processing and interpretation]. / Hemocultivos en urgencias pediátricas. Guía práctica de recomendaciones: indicaciones, técnica de extracción, procesamiento e interpretación.

Blood culture (BC) is the gold standard when a bacteraemia is suspected, and is one of the most requested microbiological tests in paediatrics. Some changes have occurred in recent years: the introduction of new vaccines, the increasing number of patients with central vascular catheters, as well as the introduction of continuous monitoring BC systems. These changes have led to the review and update of different factors related to this technique in order to optimise its use. A practice guideline is presented with recommendations on BC, established by the Spanish Society of Paediatric Emergency Care and the Spanish Society for Paediatric Infectious Diseases. After reviewing the available scientific evidence, several recommendations for each of the following aspects are presented: BC indications in the Emergency Department, how to obtain, transport and process cultures, special situations (indications and interpretation of results in immunosuppressed patients and/or central vascular catheter carriers, indications for anaerobic BC), differentiation between bacteraemia and contamination when a BC shows bacterial growth and actions to take with a positive BC in patients with fever of unknown origin.

Factores predictores de contaminación ante un hemocultivo con crecimiento bacteriano en Urgencias / Predictive factors of contamination in a blood culture with bacterial growth in an Emergency Department

Introducción: El objetivo del estudio es identificar factores predictores de contaminación ante un hemocultivo (HC) con crecimiento bacteriano realizado en un servicio de Urgencias. Pacientes y métodos Estudio prospectivo, observacional-analítico. Se incluyen los pacientes de uno a 36 meses, febriles, sin factores de riesgo para bacteriemia, con un HC realizado en el Servicio de Urgencias entre noviembre de 2011 y octubre de 2013 en el que se observa crecimiento bacteriano. Se analizan como posibles factores predictores de contaminación: temperatura máxima, tiempo de positividad, resultado inicial de la tinción de Gram, leucocitos totales, neutrófilos totales, neutrófilos inmaduros y proteína C reactiva (PCR). Resultados: Se incluyen 169 casos. El crecimiento bacteriano del HC se considera significativo (positivo) en 30 (17,8%), y contaminado en 139 (82,2%). Todos los factores predictores analizados, a excepción de la temperatura, presentan diferencias estadísticamente significativas entre los 2 grupos. Los 3 mejores predictores de contaminación son la PCR, el tiempo de positividad y el resultado inicial de la tinción de Gram. El valor predictivo positivo de una PCR≤30mg/L, un tiempo de positividad≥16h y una tinción de Gram con morfología bacteriana considerada como probable contaminación es del 95,1, 96,9 y 97,5%, respectivamente; el valor predictivo positivo es del 100% para la combinación de los 3 factores. Se reevalúan el 8,3% de los pacientes con un HC contaminado dados de alta inicialmente a domicilio. Conclusiones: La mayoría de HC con crecimiento bacteriano son finalmente considerados contaminados. El resultado inicial de la tinción de Gram, el tiempo de positividad y el valor de la PCR permiten identificarlos precozmente. Su pronta detección permitirá reducir las repercusiones negativas derivadas de los mismos (AU)

Introduction: The aim of this study is to identify predictive factors of bacterial contamination in positive blood cultures (BC) collected in an emergency department. Patients and methods: A prospective, observational and analytical study was conducted on febrile children aged on to 36 months, who had no risk factors of bacterial infection, and had a BC collected in the Emergency Department between November 2011 and October 2013 in which bacterial growth was detected. The potential BC contamination predicting factors analysed were: maximum temperature, time to positivity, initial Gram stain result, white blood cell count, absolute neutrophil count, band count, and C-reactive protein (CRP). Results: Bacteria grew in 169 BC. Thirty (17.8%) were finally considered true positives and 139 (82.2%) false positives. All potential BC contamination predicting factors analysed, except maximum temperature, showed significant differences between true positives and false positives. CRP value, time to positivity, and initial Gram stain result are the best predictors of false positives in BC. The positive predictive values of a CRP value≤30mg/L, BC time to positivity≥16h, and initial Gram stain suggestive of a contaminant in predicting a FP, are 95.1, 96.9 and 97.5%, respectively. When all 3 conditions are applied, their positive predictive value is 100%. Four (8.3%) patients with a false positive BC and discharged to home were revaluated in the Emergency Department. Conclusions: The majority of BC obtained in the Emergency Department that showed positive were finally considered false positives. Initial Gram stain, time to positivity, and CRP results are valuable diagnostic tests in distinguishing between true positives and false positives in BC. The early detection of false positives will allow minimising their negative consequences (AU)

[Predictive factors of contamination in a blood culture with bacterial growth in an Emergency Department]. / Factores predictores de contaminación ante un hemocultivo con crecimiento bacteriano en Urgencias.

INTRODUCTION: The aim of this study is to identify predictive factors of bacterial contamination in positive blood cultures (BC) collected in an emergency department. PATIENTS AND METHODS: A prospective, observational and analytical study was conducted on febrile children aged on to 36 months, who had no risk factors of bacterial infection, and had a BC collected in the Emergency Department between November 2011 and October 2013 in which bacterial growth was detected. The potential BC contamination predicting factors analysed were: maximum temperature, time to positivity, initial Gram stain result, white blood cell count, absolute neutrophil count, band count, and C-reactive protein (CRP). RESULTS: Bacteria grew in 169 BC. Thirty (17.8%) were finally considered true positives and 139 (82.2%) false positives. All potential BC contamination predicting factors analysed, except maximum temperature, showed significant differences between true positives and false positives. CRP value, time to positivity, and initial Gram stain result are the best predictors of false positives in BC. The positive predictive values of a CRP value≤30mg/L, BC time to positivity≥16h, and initial Gram stain suggestive of a contaminant in predicting a FP, are 95.1, 96.9 and 97.5%, respectively. When all 3 conditions are applied, their positive predictive value is 100%. Four (8.3%) patients with a false positive BC and discharged to home were revaluated in the Emergency Department. CONCLUSIONS: The majority of BC obtained in the Emergency Department that showed positive were finally considered false positives. Initial Gram stain, time to positivity, and CRP results are valuable diagnostic tests in distinguishing between true positives and false positives in BC. The early detection of false positives will allow minimising their negative consequences.

Infección invasiva por «Staphylococcus aureus» resistente a meticilina de origen comunitario en pacientes pediátricos sanos / Invasive infection caused by community acquired methicillin resistant Staphylococcus aureus on healthy pediatric patients

Staphylococcus aureus resistente a meticilina de adquisición comunitaria (SARM-AC) es una bacteria implicada en infecciones de diversa gravedad y localización. En este trabajo exponemos la actualidad de las infecciones por SARM-AC en pediatría, y lo ilustramos con dos ejemplos de infección virulenta en pacientes pediátricos sanos. El primer caso corresponde a una paciente con artritis séptica y neumonía necrosante por SARM-AC, y el segundo a un lactante con pleuroneumonía por SARM-AC. Ambos casos son un claro ejemplo de la relevancia de esta infección emergente en pediatría (AU)

The community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) is a bacterium that is frequently involved in severe infections and various locations. In this article we describe the actual state of CA-MRSA infections in pediatrics, and we illustrate it with two examples of virulent infection in healthy pediatric patients. The first case is in a patient with septic arthritis and necrotizing pneumonia caused by CA-MRSA, and the second one is in an unweaned baby with pleuropneumonia caused by CA-MRSA. Both cases are a clear example of the importance of this emerging infection in pediatrics (AU)

Fiebre en el lactante menor de 3 meses: incidencia de enfermedad bacteriana potencialmente grave y utilidad de los test de diagnóstico rápido virológico / Fever in infants aged less than three months: incidence of potentially serious bacterial disease and usefulness of the rapid virological diagnostic tests

Objetivos: Determinar la incidencia y la etiología de la enfermedad bacteriana potencialmente grave (EBPG), de la infección vírica y de la coinfección (vírica y bacteriana) en una muestra de lactantes febriles menores de tres meses. Métodos: Estudio prospectivo de lactantes menores de tres meses que ingresaron en nuestro centro por fiebre. A todos ellos se les realizó estudio completo de sepsis, con punción lumbar en casos seleccionados. Se define enfermedad bacteriana potencialmente grave como el crecimiento de un microorganismo bacteriano en sangre, orina o líquido cefalorraquídeo. Se determinó la presencia de virus respiratorio sincitial (VRS) y virus Influenzae A y B durante el período epidémico, y la presencia de enterovirus, por reacción en cadena de la polimerasa, en 11 pacientes menores de un mes. Para el análisis de los resultados se utilizó el programa SPSS (versión 12.0). Resultados: Se incluyeron 136 lactantes febriles menores de tres meses. Cumplían los criterios de bajo riesgo de Rochester 70 pacientes (51,5%). Los diagnósticos finales más frecuentes fueron síndrome febril sin foco e infección urinaria. En 33 casos (24,3%) se demostró una EBPG (31 urocultivos, 2 cultivos de líquido cefalorraquídeo y 7 hemocultivos resultaron positivos). La incidencia de infección vírica demostrada fue del 30,8%. En 2 pacientes se demostró coinfección vírica y bacteriana (un 4,8% del total de los pacientes infectados por virus). Se detectó la presencia de enterovirus en líquido cefalorraquídeo en 5 (45,5%) de 11 casos estudiados, ninguno de ellos mostró cultivos bacterianos positivos. Discusión: En nuestro estudio, la infección urinaria se muestra como la enfermedad bacteriana potencialmente grave con mayor incidencia, superior a la hallada en otras series. La incorporación a los algoritmos diagnósticos de los test de diagnóstico rápido virológico ayuda a seleccionar a los lactantes con menor riesgo de padecer enfermedad bacteriana, y abre nuevas perspectivas en el manejo del lactante febril menor de tres meses (AU)

Aims: To assess the incidence and aetiology of potentially serious bacterial disease (PSBD), viral infection and viral-bacterial coinfection in a sample of febrile infants aged less than three months. Methods: Prospective study of infants aged less than three months admitted to our hospital because of fever. A complete sepsis study was performed in all cases, with lumbar tap in selected cases. PSBD is defined as the growth of bacteria in blood, urine or cebrospinal fluid (CSF). The presence of Respiratory Syncitial Virus and of influenza A and B viruses was assessed during the epidemic period, and enteroviruses were investigated using the polymerase chain reaction in eleven patients aged less than one month. The SPSS 12.0 software was used for the analysis. Results: The study population comprised 136 infants aged less than three months. Seventy patients (51.5%) met the Rochester low-risk criteria. The most common final diagnoses were non-focal febrile syndrome and urinary infection. PSBD was demonstrated in 33 cases (24.3%) (31 urine cultures, 2 CSF cultures and 7 blood cultures were positive). The incidence of documented viral infection was 30.8%. Viral and bacterial coinfection was demonstrated in 2 cases (4.8% of the total number of virus-infected patients). Enterovirus was demonstrated in the CSF in 5 (45.5%) of 11 cases studied; none of them had positive bacterial cultures. Discussion: In the present study, urinary infection was the most frequently occurring potentially serious bacterial disease, with an incidence higher than those reported in other series. The inclusion of rapid virological diagnostic tests in the diagnostic algorithms helps in selecting those infants with lower risk of bacterial infection and opens new perspectives for the management of febrile infants aged less than three months (AU)

[Cutaneous colonization by Malassezia spp. in neonates]. / Colonización cutánea neonatal por Malassezia spp.

BACKGROUND: Malassezia spp. is a lipophilic yeast considered to be a normal component of the human skin flora. It has been associated with sepsis in patients receiving intravenous infusion of lipid emulsions through central venous catheters (CVC). Current evidence indicates a high rate of skin colonization in healthy adults, in contrast with the low rate of colonization in prepubertal children. Of note is the high prevalence of colonized infants in the neonatal intensive care unit (NICU). METHODS: We performed a prospective open observational study of colonization in all infants admitted to the NICU during a nine-month period (October 1997-June 1998). Length of stay in the unit, birthweight and the use of CVC for parenteral fat infusion were evaluated. RESULTS: Seventy-seven neonates were included in the study. The mean length of stay in the NICU was 24 days. A total of 63.6 % weighed less than 2,500 g at birth and 72 % were given parenteral nutrition supplemented with fat emulsion through a CVC. The overall rate of colonization in the unit was 41.5 and 75 % of the patients became colonized within the first two weeks of admission. CONCLUSIONS: These data emphasize the need for preventive measures to reduce the transmission of these yeasts in the NICU and to prevent the occurrence of neonatal sepsis due to Malassezia spp. in immunologically immature infants.

Colonización cutánea neonatal por Malassezia spp / Cutaneous colonization by malassezia spp. in neonates

Fundamentos: Malassezia spp. es una levadura que forma parte de la microflora cutánea. Está demostrado que puede ser agente etiológico de sepsis en pacientes portadores de catéter venoso central (CVC) que reciben emulsiones lipídicas por vía parenteral. Se conoce que las personas adultas sanas están altamente colonizadas en las zonas con mayor densidad de glándulas sebáceas, en contraste con la baja densidad de colonización en niños por debajo de la edad puberal. Cabe destacar la elevada densidad de colonización en niños ingresados en unidades neonatales de cuidados intensivos (UCI). Métodos: Se realizó un estudio prospectivo observacional abierto de la colonización cutánea de todos los recién nacidos ingresados en la UCI, durante un período de 9 meses (octubre de 1997-junio de 1998) valorando el tiempo de permanencia en la unidad, el peso al nacimiento y la presencia de CVC por el que se administraba la alimentación parenteral. Resultados: Se controlaron 77 recién nacidos, cuya permanencia media en la unidad fue de 24 días. El 63,6% pesaban menos de 2.500 g al nacer y el 72% precisaron alimentación parenteral suplementada con lípidos, suministrada a través del CVC. La colonización global en esta unidad fue del 41,5% de los que el 75% se positivizó antes de las 2 semanas del ingreso. Conclusiones: El conocimiento de esta elevada tasa de colonización en la UCI neonatal implica extremar todas las medidas preventivas necesarias para reducir al mínimo la transmisión de esta levadura a través de la unidad, con el fin de prevenir una eventual sepsis neonatal por Malassezia spp. en este grupo de pacientes (AU)

[Routes of endotracheal colonization in patients with mechanical ventilation]. / Rutas de colonización traqueal en pacientes sometidos a ventilación mecánica.

OBJECTIVE: We prospectively evaluated the frequency and route of endotracheal colonization in intubated children in order to know what microorganisms, either by primary infection or through previous colonization of oropharynx and/or stomach and progression towards the lower respiratory tract, are responsible for these infections. PATIENTS AND METHODS: Oropharyngeal, tracheal and gastric samples of 43 patients were collected for culture at the moment of intubation and at 24-h intervals for 4 days. The colonization route for each endotracheal microorganism was classified depending on the initial isolation site. Isolated microorganisms were considered as belonging to the same strain if the biochemical pattern and antibiogram were identical. RESULTS: Of the patients studied, 84% presented positive cultures the first day. Tracheal colonization was detected at day 1 in 22 patients (51%) and in 35 (82%) at the end of the study. A colonization sequence was seen in 18 patients (41%). The microorganisms most frequently isolated were S. aureus, P. aeuruginosa and C. albicans. CONCLUSIONS: The mechanisms of tracheal colonization in intubated children is similar to adults. Oropharynx colonization is the key antecedent. Prophylaxis measures should avoid the proliferation at the oropharyngeal and/or gastric level.

[Neonatal infections by Streptococcus agalactiae]. / Infecciones neonatales por Streptococcus agalactiae.

OBJECTIVES: The objectives of the study were to evaluate: 1) The incidence and characteristics of neonatal infections by S. agalactiae in the Hospital Sant Joan de Déu of Barcelona, 2) the efficiency of a microbiological control during the third quarter of pregnancy in order to detect colonization by this microorganism; and 3) the efficiency of intrapartum prophylaxis. MATERIAL AND METHODS: Neonatal infections that took place between May 1991 and December 1994 have been studied. Children were born from women controlled in our hospital (7.772 pregnant women) or from women who delivered in other health centers. RESULTS: Nineteen newborn children with an invasive infection and four asymptomatic bacteriemias were diagnosed and treated during the above mentioned period of time. Early forms of the illness were sepsis (eight cases), meningitis (four cases) and arthritis (one case), whereas late forms were comprised of four cases of meningitis and two of arthritis. Three of the neonates died (mortality rate of 15.7%) and two of them developed neurologic sequelae. CONCLUSIONS: The microbiological control during pregnancy in order to detect S. agalactiae carriers, as well as intrapartum antibiotic prophylaxis contributes to reduce the number of this sort of infections. Negative results of cultures carried out during the third quarter of pregnancy do not exclude a carrier state at delivery, therefore, so posterior controls are necessary until the end of pregnancy.