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.

[Characteristics of urinary tract infections in different patient subpopulations and depending on the bladder emptying system]. / Características de las infecciones urinarias en pacientes con vejiga neurógena según el sistema de vaciado vesical utilizado en comparación con pacientes sin vejiga neurógena.

INTRODUCTION: To analyze the prevalence and etiology of urinary tract infection in patients with neurogenic bladder depending on the bladder emptying system used as compared to a population with no neurological impairment. To assess perception of urinary tract infection by patients with neurogenic bladder. MATERIALS AND METHODS: An epidemiological and prospective study was conducted on 283 patients, in whom a total of 283 urethral cultures were performed. Of these, 106 came from patients with neurological damage, 28 from a control group with no neurological impairment, 74 from patients admitted to the intensive care unit (ICU) of our hospital, and 75 from patients who attended the emergency room for symptoms of acute urinary tract infection. The sensitivity and specificity of patient perception as indicative of urinary tract infection was analyzed using ROC curves. RESULTS: Positive urethral cultures were found in 66% of patients with neurological damage and 25% of control patients. Within the neurological group, patients with the highest rates of positive urethral cultures were those with myelomeningocele (MMC) (81.5%) and spinal cord injuries (71.7%), with a statistically significant difference (p=0.01). The microorganism most commonly found in all subgroups was Escherichia coli, followed by Enterococcus faecalis and Pseudomonas aeruginosa in the neurological subgroup, Enterococcus faecalis and Proteus mirabilis in the control subgroup, and Klebsiella pneumoniae and Staphylococcus agalactiae in the emergency room subgroup. In the ICU subgroup, the most commonly found microorganism was Enterococcus faecalis, followed by Escherichia coli and Pseudomonas aeruginosa. Sensitivity for perception by neurological patients as an indication of the presence of urinary tract infection was 97.2%, as compared to 80% in the control group. Specificity was low in both groups. CONCLUSIONS: E. coli was the microorganism found in positive urethral cultures from all subgroups, except in the ICU group. The groups with the highest urinary tract infection rates were patients with MMC and spinal cord injuries. Sensitivity and specificity (as measured using ROC curves) for perception by neurological patients as an indication of the presence of urinary tract infection was higher in neurological patients than in the non-neurological control group (p=0.0004, area: 0.643).

Características de las infecciones urinarias en pacientes con vejiga neurógena según el sistema de vaciado vesical utilizado en comparación con pacientes sin vejiga neurógena / Characteristics of urinary tract infections in different patient subpopulations and depending on the bladder emptying system

Introducción: La infección urinaria es una patología muy frecuente en las disfunciones miccionales neurógenas. Existen pocos trabajos sobre dicha problemática y menos respecto al sistema de vaciado vesical empleado en estos casos (sonda vesical permanente, colector permanente, cateterismos intermitentes). El objetivo de este estudio fue analizar la prevalencia y la etiología de la infección urinaria en pacientes afectados de vejiga neurógena según su sistema de vaciado vesical en comparación con una población no neurógena, así como valorar la percepción de la infección urinaria en los pacientes afectados de vejiga neurógena. Material y métodos: Se realizó un estudio epidemiológico y prospectivo consecutivo en el que se incluyó a 283 pacientes a los que se les practicó un total de 283 urocultivos. De éstos, 106 procedían de pacientes con lesión neurológica, 28 de un grupo control no neurógeno, 74 de pacientes ingresados en la Unidad de Cuidados Intensivos (UCI) de nuestro hospital y 75 de pacientes que acudieron a urgencias por sintomatología de infección aguda del tracto urinario. Se analizó la sensibilidad y la especificidad que tiene la percepción del propio paciente como indicativo de infección urinaria mediante las curvas ROC. Resultados: El 66% de los pacientes con lesión neurológica presentó urocultivos positivos respecto al 25% de los controles. Dentro del grupo neurológico, el colectivo con más urocultivos positivos fueron pacientes con mielomeningocele (81,5%) y con lesión medular (71,7%), con una significación estadística (p=0,01). El microorganismo más frecuente en todos los subgrupos fue Escherichia coli en primer lugar, seguido de Enterococcus faecalis y Pseudomonas aeruginosa en el subgrupo neurológico, de E. faecalis y Proteus mirabillis en el subgrupo control y de Klebsiella pneumoniae y Streptococcus agalactiae en el subgrupo de urgencias. En el subgrupo de la UCI, el microorganismo más frecuente en primer lugar fue E. faecalis, seguido de E. coli y P. aeruginosa. La sensibilidad para la percepción del paciente neurológico como indicativa de tener una infección urinaria fue del 97,2 respecto al 80% en el grupo control. Las especificidades fueron bajas en ambos grupos. Conclusiones: El microorganismo hallado en los urocultivos positivos en todos los subgrupos fue E. coli, excepto en los de la UCI. Los colectivos con más infecciones urinarias fueron mielomeningocele y lesión medular. La sensibilidad y la especificidad (medidas con la curva ROC) para la percepción del paciente neurológico como indicativas de tener una infección urinaria fueron más altas en los pacientes neurológicos respecto al grupo control no neurológico (p=0,0004; área: 0,643) (AU)

Introduction: To analyze the prevalence and etiology of urinary tract infection in patients with neurogenic bladder depending on the bladder emptying system used as compared to a population with no neurological impairment. To assess perception of urinary tract infection by patients with neurogenic bladder. Materials and methods: An epidemiological and prospective study was conducted on 283 patients, in whom a total of 283 urethral cultures were performed. Of these, 106 came from patients with neurological damage, 28 from a control group with no neurological impairment, 74 from patients admitted to the intensive care unit (ICU) of our hospital, and 75 from patients who attended the emergency room for symptoms of acute urinary tract infection. The sensitivity and specificity of patient perception as indicative of urinary tract infection was analyzed using ROC curves. Results: Positive urethral cultures were found in 66% of patients with neurological damage and 25% of control patients. Within the neurological group, patients with the highest rates of positive urethral cultures were those with myelomeningocele (MMC) (81.5%) and spinal cord injuries (71.7%), with a statistically significant difference (p=0.01). The microorganism most commonly found in all subgroups was Escherichia coli, followed by Enterococcus faecalis and Pseudomonas aeruginosa in the neurological subgroup, Enterococcus faecalis and Proteus mirabilis in the control subgroup, and Klebsiella pneumoniae and Staphylococcus agalactiae in the emergency room subgroup. In the ICU subgroup, the most commonly found microorganism was Enterococcus faecalis, followed by Escherichia coli and Pseudomonas aeruginosa. Sensitivity for perception by neurological patients as an indication of the presence of urinary tract infection was 97.2%, as compared to 80% in the control group. Specificity was low in both groups. Conclusions: E. coli was the microorganism found in positive urethral cultures from all subgroups, except in the ICU group. The groups with the highest urinary tract infection rates were patients with MMC and spinal cord injuries. Sensitivity and specificity (as measured using ROC curves) for perception by neurological patients as an indication of the presence of urinary tract infection was higher in neurological patients than in the non-neurological control group (p=0.0004, area: 0.643) (AU)

Molecular epidemiology for local outbreaks of methicillin resistant Staphylococcus aureus (MRSA). The need for several methods.

Subtyping isolates may be useful for epidemiological studies of methicillin-resistant-Staphylococcus aureus (MRSA) outbreaks. Among subtyping methods, DNA-based techniques have been applied very effectively for this purpose. An outbreak of MRSA infections took place in one hospital in Barcelona early during 1991. From the beginning of the outbreak to December 92, 70 MRSA isolates from different patients and sources were collected. All strains were evaluated by restriction endonuclease analysis of plasmid DNA (REAP) and macrorestriction endonuclease analysis of genomic DNA using Sma I and pulsed-field-gel-electrophoresis (PFGE). Plasmid screening and REAP using Hind III demonstrated two plasmid subtypes: subtype A showing a large plasmid, and subtype B showing the same large plasmid plus a smaller one. Subtypes A and B corresponded to the more recent and older isolates, respectively, suggesting the loss of the small plasmid during the epidemic. PFGE using Sma I displayed two closely related profiles (PFGE subtype A and A'; CS = 0.90). These subtypes were different from those subtypes exhibited from 4 methicillin-susceptible-Staphylococcus aureus (MSSA) isolates from the same hospital and from 2 epidemiologically unrelated MRSA isolates. Almost all isolates showing PFGE subtype A preceded those isolates showing PFGE subtype A'. This fact and the similarity between both subtypes suggested minor chromosomal DNA rearrangement during the outbreak from a unique strain. While PFGE using Sma I is a useful tool in evaluation of clonal dissemination, our data suggest epidemic or local outbreaks may need several methods to best delineate the source and spread of MRSA strains. The reproducibility and discriminatory power of REAP makes it a useful adjunct in this context.

[Use of DNA probes labelled with radioisotopes in the mycobacteria laboratory]. / Utilidad de las sondas de ADN, marcadas con isótopos radiactivos en el laboratorio de micobacterias.

We have studied 540 mycobacterial strains isolated in Lowestein-Jensen medium and 133 samples of different pathologic products against commercialized 125I-DNA Mycobacterium tuberculosis complex, Mycobacterium avitum-intracellulare and Mycobacterium gordonae. The sensitivity, specificity and positive and negative predictive values against isolated strains was 100% for the 3 studied probes. The 125I-DNA probe specific for M. tuberculosis complex is studied in samples with positive bacciloscopy; statistic values vary according to the cutting point of the different percentages of hybridization: at 1.5% the sensitivity, specificity and predictive negative and positive values are 38.6%, 71.4%, 97.5%, and 9.4% respectively, while if the cutting point percentage is 3% these values are: 33.1%, 100%, 100%, and 7.8% respectively. We believe that with these probes the identification time is limited to time needed for the incubation of prime cultures, and in some cases it can be performed on the day the samples reach the laboratory.

[Childhood legionellosis]. / Legionelosis infantil.

Four cases of hospital acquired pneumonia are reported in children aged from 10 days to 7 years, in whom L. pneumophila serogroup 6 was isolated. All patients were sporadic cases occurring during a two year period (1987-1988) in the Pediatric Hospital of our institution. L. pneumophila was isolated in samples of pleural fluid, lung biopsy, tracheal aspirate, bronchial brushing and bronchoalveolar lavage. All our patients were immunologically depressed and three died. Only in two cases of erythromycin therapy was administered, as the etiology of their pneumonia was not suspected. The literature on other reported cases of infantile legionellosis is discussed.