Diagnóstico de patógenos respiratorios mediante PCR en tiempo real: una realidad en el Hospital Roberto del Río / Diagnosis of respiratory pathogens using real-time PCR: a reality at the Roberto del Río Hospital

La técnica de la reacción de polimerasa en cadena (PCR) en tiempo real o PCR está disponible en el Hospital Roberto del Río desde el 2015. Esta técnica rápida y muy sensible, mejora los tiempos de respuesta y facilita la toma de decisiones clínicas. Sin embargo, es importante conocer los distintos aspectos del método para hacer una correcta interpretación clínica de un resultado de PCR.

Real time polymerase chain reaction (PCR) is a rapid and sensitive technique. It improves answer time for clinical decisions. It is important to know it well for a better clinical understanding.

Infección por adenovirus en el Hospital de niños Roberto del Río 2016 / Adenovirus infection at the Roberto del Río children's Hospital 2016

En los meses de invierno, las enfermedades respiratorias representan la primera causa de hospitalización en hospitales pediátricos. La mayoría de estas enfermedades son causadas por virus, dentro de los cuales se encuentra el adenovirus (AdV), el cual puede generar infecciones diseminadas graves, secuelantes e incluso letales y se caracteriza por tener una rápida transmisión entre pacientes, generando brotes intrahospitalarios. Se identificó a 54 pacientes hospitalizados con infección por adenovirus en el periodo de marzo-julio del 2016 con una edad promedio de 18,3 meses, de los cuales 23 casos fueron infecciones asociadas a la atención de salud (IIAS) y 2 tuvieron desenlace fatal. Los casos de IIAS, se asociaron a una mayor tasa de hospitalización prolongada (p= <0.01), ingreso a UPC (p= <0.01) y uso de ventilación mecánica (p= <0.01). No se encontró asociación entre la presencia de antecedentes mórbidos con el desarrollo de IIAS. Las IIAS por adenovirus se asocia a una hospitalización prolongada, ingreso de unidades de alta complejidad y necesidad de uso de ventilación mecánica. Dado que el adenovirus se transmite a través de contactos directo, aerosoles y fómites, las medidas básicas de precaución de contacto y de aislamiento permiten reducir los contagios nosocomiales, recayendo la responsabilidad en todo el equipo de salud a cargo.

Respiratorio deseases are frequent in winter times. being the main cause of hospital admissions. Viral infecciones are the main etiology, and adenovirus infección clould lead to severe disease, with cross infections. We identified 54 patients admitted to the Roberto del Río Childrens hospital in 2016, with a mean age of 18,3 months old; 23 cases where nosocomial infection, and 2 were fatal. Hospital acquired adenovirus infection were associated to long hospital stay (p= <0.01), intensive care admission (p= <0.01) and ventilatory support (p= <0.01). We did not find previous illness conditions. Adenovirus hospital acquired infection is associated with longer hospital stay and dead. Adenovirus is transmitted with direct contact, aerosols and fomites, therefore basic contact precautions are important.

Evaluation of the Sebia Capillarys 3 Tera and the Bio-Rad D-100 Systems for the Measurement of Hemoglobin A1c.

OBJECTIVES: We evaluated the Bio-Rad (Irvine, CA) D-100 and the Sebia (Lisses, France) Capillarys 3 Tera for the measurement of hemoglobin A1c (HbA1c) in venous blood samples. METHODS: Whole-blood samples and control material were analyzed with the D-100 and Capillarys 3 Tera and compared with our routine method, HLC-723G7 (Tosoh, Tokyo, Japan). An evaluation protocol to test precision, trueness, linearity, carryover, and selectivity was set up according to Clinical and Laboratory Standards Institute guidelines. The results were presented in National Glycohemoglobin Standardization Program and International Federation of Clinical Chemistry (IFCC) units. RESULTS: Both systems showed excellent precision (total coefficients of variation <2%, IFCC) and bias (<0.3% or 3 mmol/mol). Linearity was demonstrated for HbA1c values from 3.8% (18 mmol/mol) to 18.5% (179 mmol/mol). Results were correlated with the routine method using Bland-Altman analysis, showing a mean difference of 0.33% or 3.6 mmol/mol for the D-100 and of 0.25% or 2.6 mmol/mol for the Capillarys 3 Tera vs HLC-723G7. None of the automated instruments were prone to interferences by labile HbA1c (≤10 g/L glucose), carbamylated hemoglobin (≤0.5 mmol/L potassium cyanate), hemoglobin variants, bilirubin (≤15 mg/dL), and triglycerides (≤3,360 mg/dL). CONCLUSIONS: The Bio-Rad D-100 and the Sebia Capillarys 3 Tera instruments performed well for the determination of HbA1c in terms of quality criteria as well as for sample throughput.

The copy number of the catabolic plasmid pJP4 affects growth of Ralstonia eutropha JMP134 (pJP4) on 3-chlorobenzoate.

Ralstonia eutropha JMP134 (pJP4) grows on 3-chlorobenzoate (3-CB) or 2,4-dichlorophenoxyacetate (2,4-D). The copy number of chlorocatechol genes has been observed to be important for allowing growth of bacterial strains on chloroaromatic compounds. Despite the fact that two functional chlorocatechol degradation tfd gene clusters are harbored on plasmid pJP4, a single copy of the region comprising all tfd genes in strain JMP134-F was insufficient to allow growth on 3-CB, whereas growth on 2,4-D was only slightly retarded compared to the wild-type strain. Using competitive PCR, approximately five copies of pJP4 per genome were observed to be present in the wild-type strain, whereas only one copy of pJP4 was present per chromosome in strain JMP134-F. Therefore, several copies of pJP4 per chromosome are required for full expression of the tfd-encoded growth abilities in the wild-type R. eutropha strain.

Molecular characterization of a deletion/duplication rearrangement in tfd genes from Ralstonia eutropha JMP134(pJP4) that improves growth on 3-chlorobenzoic acid but abolishes growth on 2,4-dichlorophenoxyacetic acid.

Ralstonia eutropha JMP134(pJP4) is able to grow on minimal media containing the pollutants 3-chlorobenzoate (3-CB) or 2,4-dichlorophenoxyacetate (2,4-D). tfd genes from the 88 kb plasmid pJP4 encode enzymes involved in the degradation of these compounds. During growth of strain JMP134 in liquid medium containing 3-CB, a derivative strain harbouring a approximately 95 kb plasmid was isolated. This derivative, designated JMP134(pJP4-F3), had an improved ability to grow on 3-CB, but had lost the ability to grow on 2,4-D. Sequence analysis of pJP4-F3 indicated that the plasmid had undergone a deletion of approximately 16 kb, which included the tfdA-tfdS intergenic region, spanning the tfdA gene to a previously unreported IS1071 element. The loss of the tfdA gene explains the failure of the derivative to grow on 2,4-D. A approximately 23 kb duplication of the region spanning tfdR-tfdD(II)C(II)E(II)F(II)-tfdB(II)-tfdK-ISJP4-tfdT-tfdC(I)D(I)E(I)F(I)-tfdB(I), giving rise to a 51-kb-long inverted repeat, was also observed. The increase in gene copy number for the tfdCD(DC)EF gene cluster may provide an explanation for the derivative strain's improved growth on 3-CB. These observations are additional examples of the metabolic plasticity of R. eutropha JMP134, one of the more versatile pollutant-degrading bacteria.