Comparison between five PCR techniques for the diagnosis of SARS-CoV-2.

OBJECTIVE: Since the first cases of SARS-CoV-2 appeared, there have been numerous techniques that have been developed for the diagnosis or monitoring of infection, both direct and serological techniques. Choosing a good diagnostic tool is essential for epidemiological control. The objective was to compare five commercialized RT-PCR techniques in real time, in sensitivity, specificity and agreement for the detection of SARS-CoV-2. METHODS: Five commercial RT-PCR kits for the detection of SARS-CoV-2 were compared. Eight known positive samples were taken and subjected to seven different dilutions or concentrations, and another 135 negative samples were used to determine sensitivity, specificity, and agreement values. RESULTS: The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the Palex, Roche and GeneXpert techniques with respect to Seegene were identical, corresponding to 98.21%, 100%, 100% and 99.26% respectively. For Becton Dickinson the sensitivity was 89.28%, the specificity of 100%, the PPV of 100% and the NPV of 95.74%. The agreement using the Kappa index for Palex, Roche and GeneXpert was 0.9892, while the agreement for Becton Dickinson was with a Kappa index of 0.9215. CONCLUSIONS: All commercial RT-PCR kits had high sensitivities and specificities, as well as PPV, NPV, and concordance.

[Evaluation of a new device for sample collection, transport and detection of Group B Streptococcus in pregnant women]. / Evaluación de un nuevo dispositivo para la recogida de la muestra, transporte y detección del estreptococo del grupo B en mujeres embarazadas.

We have designed a new device that combines sample collection, transportation, culture and detection of Group B Streptococcus (GBS), requiring no additional processing in the clinical laboratory. The objective was to evaluate the performance of this device for GBS detection in pregnant women. The new prototype was compared to direct plating of vaginal-rectal swabs onto Granada solid media plates. Direct plating method detected 124 positive samples out of 600 (20.6%) whereas the new device detected 10 additional positive samples (134/600, 22.3%). This new device (patent-protected) could be considered for routine GBS screening.

[Development of a PCR for the detection and quantification of parasitism by Demodex folliculorum infestation in biopsies of skin neoplasms periocular area]. / Desarrollo de una PCR para la detección y cuantificación de la parasitación por Demodex folliculorum en biopsias de neoplasias cutáneas del área periocula.

OBJECTIVE: To standardize the relative quantification by mass of tissue parasitism by Demodex folliculorum infestation from neoplastic skin biopsies periocular using molecular amplification to study the possible relationship of the appearance of eyelid basal cell carcinoma with the presence and density of the mite in later works. METHODS: A quantitative PCR was developed real-time probes TaqMan. PCR was tested in a pilot 46 actual biopsy samples nodular basal cell carcinoma series. RESULTS: The sensitivity was placed with a detection limit of between 1 and 10 copies / µl. 50% (23/46) of the biopsies were positive for D. folliculorum. The specificity was 100% confirmed by sequencing. CONCLUSIONS: The technique shows good results for sensitivity and specificity that can make it useful as a tool for studies of cause and effect D. folliculorum and basal cell carcinoma.

Evaluación de un test de detección antigénica rápido para el diagnóstico de urgencias de gripe A H1N1 pandémica en la población pediátrica / Evaluation of a rapid antigen detection test for the diagnosis of emergency influenza A H1N1 pandemic in a pediatric population

Introduction: The immunochromatographic capillary method (ICC) provides rapid results that can help the individual treatment of patients. The aim was to evaluate the diagnostic accuracy of an ICC rapid test for detection of influenza virus in pediatric emergencies. Material and methods: 225 samples were collected from pediatric patients and tested by ICC and RT-PCR (as gold standard).Results: Overall, the ICC sensitivity and specificity values were 51% and 100%, respectively. Sensitivity in throat swabs and nasal aspirates was 46.6% and 52.6% respectively. In regards to gernder, flu was diagnosed by PCR in 21 out of 110males (19.1%) and 32 out of 115 females (27.8%).Conclusion: Although the ICC displayed limited sensitivity, the excellent positive predictive value it could be useful in the presumptive diagnosis of emergency(AU)

Introducción: La inmunocromatografía capilar (ICC) ofrece resultados rápidos que pueden ayudar al tratamiento individual de los pacientes. El objetivo ha sido evaluar la eficacia diagnóstica de un test rápido de ICC para la detección virus gripales y su aplicación en urgencias pediátricas. Material y métodos: Se analizaron 225 muestras mediante ICC y RT-PCR (método de referencia) procedentes de pacientes pediátricos. Resultados: La sensibilidad y especificidad media hallada para la ICC en el conjunto de muestras fue del 51 y 100%, respectivamente. La sensibilidad en frotis faríngeos fue del 46,6% y en aspirados nasales fue del 52,6%. En relación con el sexo, mediante PCR se diagnostica la gripe en 21/110 hombres (19,1%) y 32/115 mujeres (27,8%).Conclusión: La ICC presenta una sensibilidad limitada, aunque por su excelente especificidad sería útil su uso en el diagnóstico presuntivo de urgencias(AU)

Características epidemiológicas de las bronquiolitis causadas por el virus respiratorio sincitial y el metapneumovirus humano en pacientes pediátricos / Epidemiological characteristics of bronchiolitis caused by respiratory sincytial virus and human metapneumovirus in pediatric patients

Introducción: La bronquiolitis es una enfermedad de las vías respiratorias que se produce durante los primeros años de vida. Métodos: Desde febrero de 2008 hasta diciembre de 2009 se estudiaron los casos de bronquiolitis en una población pediátrica de 3 años de edad. Se procesaron 1.012 aspirados nasales para la detección antigénica rápida frente al virus respiratorios incitial (VRS) y 753 para la técnica de amplificación de ácidos nucleicos de metapneumovirus humano (MPVh). Resultados: En las 1.012 muestras recibidas se realizó la detección antigénica de VRS; 195 (19,27%) resultaron positivas, correspondientes a 185 pacientes. En 763 muestras se realizó la detección de MPVh; 60 (7,86%) resultaron positivas, que correspondían a 50 pacientes. El mayor porcentaje de los casos se dieron en pacientes menores de 6 meses. Se observó una distribución estacional de los casos. Conclusión: En nuestro medio, los MPVh presentan una menor incidencia que los VRS; además, la distribución epidemiológica del VRS precede, y con picos más bruscos, a la del MPVh (AU)

Introduction: Bronchiolitis is a disease of the respiratory tract that takes place during the first years of life. Methods: In February 2008- December 2009 the bronchiolitis pediatric population from 0 to 3 years of age was studied. 1,012 nasal aspirates were processed for the rapid antigen detection of RSV and 753 for the technology of amplification of nucleic acids of hMPV. Results: In 1,012 samples the rapid antigen detection of RSV was carried out showing 195 (19.27%) positives, corresponding to185 patients. In 763 samples the detection of hMPV was carried out, showing 60 (7.86%) positives and they corresponded to 50 patients. The major percentage of the cases were given in patients <6 months. A seasonal distribution of the cases was observed. Conclusion: In our environment, the hMPV show a minor incidence than the RSV and the epidemiological distribution of the RSV precedes, and with more sudden sharp point, than to the hMPV (AU)

[Variability in the sensitivity to tigecycline against Acinetobacter baumannii in different culture media]. / Variabilidad en la sensibilidad de tigeciclina frente a Acinetobacter baumannii en diferentes medios de cultivo.

INTRODUCTION: The tigecycline may represent a therapeutic alternative for the control of multiresistant A. baumannii, although there is no consensus regarding the cutoff points for sensitivity or variability of MIC as a function of culture medium used for the antibiogram against this microorganism. Therefore, our objective was to verify this variability, and propose the culture medium that comes closest to the standard method. METHODS: We selected 41 strains of carbapenem-resistant A. baumannii. We analyzed the sensitivity to tigecycline in different culture media: Mueller Hinton agar Oxoid commercial (C-MH), Mueller Hinton fresh agar BD and Co., USA (F-MH) and ISO-sensitest fresh agar Oxoid, using the E-test and disk. The MICs were compared against those obtained using the technique standard of macrodilution. RESULTS: The mean MIC and inhibition diameters obtained in the different culture media corresponded to 9.26 mg/L and 15.1 mm in diameter for MH-C, 1.71 mg/L and 22.7 mm for MH-F; 2.68 mg/L and 20.8 mm for ISO-sensitest. Half the MIC obtained by the standard method of dilution was 0.47 mg/L (SD =0.21), with values between 0.25 and 1 mg/L. CONCLUSION: In the three growth media studied, MICs superior to the standard are observed, which is false to interpret resistance in many cases. However, the medium that comes closer more that of reference is the MH-F.

[HIV seroprevalence in the population treated in a hospital emergency department: analysis by pooled batches of serum]. / Seroprevalencia del VIH en población atendida en un Servicio de Urgencias: análisis por lotes de sueros.

INTRODUCTION: The current number of Human Immunodeficiency Virus (HIV) infected people is not known in Spain as there is no national registry. This study has aimed to estimate the prevalence of HIV infection in the population treated in a hospital emergency department (ER) as an epidemic and risk of exposure indicator during healthcare activity and to assess the differences observed regarding previous estimates. MATERIAL AND METHODS: We conducted a cross-sectional study of all the sera received in the ER anonymously. The final size of the pools was 5 sera. HIV antibody screening was performed using the 4th generation ELFA technique and confirmation was performed by Western Blot. RESULTS: Seven out of the 270 pools made from 1,347 sera obtained were reactive. The individualized analysis confirmed 6 sera to be positive and 1 serum to be false positive. The observed prevalence was 0.52% (95% CI 0.10-0.94). Prevalence fell 0.87% in comparison to the years 1990-1991, although this was not statistically significant (p = 0.08). DISCUSSION: The implementation of HIV antibodies detection through a system of pooled batches in samples collected in the ER make it possible to assess the prevalence of infection with this virus, decreasing costs with regard to individualized analysis of sera in both economic terms as well as samples handling.

Seroprevalencia del VIH en población atendida en un Servicio de Urgencias: análisis por lotes de sueros / HIV seroprevalence in the population treated in a hospital emergency department: analysis by pooled batches of serum

Introducción. En España no se conoce el número real de infectados por el virus de la inmunodeficiencia humana (VIH), al no existir un registro nacional. El objetivo de este estudio es estimar la prevalencia de infección por el VIH en la población atendida en un Servicio de Urgencias hospitalario (SUH) como indicador epidemiológico y de riesgo de exposición laboral durante la actividad asistencial, así como evaluar las diferencias observadas respecto a estimaciones previas. Material y métodos. Se realizó un estudio transversal de todos los sueros recibidos por el SUH de forma anónima. El tamaño final de los lotes confeccionados fue de 5 sueros. La detección de anticuerpos del VIH se realizó mediante la técnica de ELFA de cuarta generación y la confirmación mediante western blot. Resultados. De los 270 lotes confeccionados con los 1.347 sueros obtenidos, 7 lotes resultaron reactivos. El análisis individualizado de los sueros confirmó 6 sueros positivos y un suero falso positivo. La prevalencia observada fue del 0,52% (IC 95% 0,10-0,94). La caída en la prevalencia con respecto a los años 1990-1991 fue del 0,87%, aunque no resultó una diferencia estadísticamente significativa (p = 0,08).Discusión. La aplicación del estudio de lotes de sueros en la detección de anticuerpos frente al VIH en muestras recogidas en los SUH permite evaluar la prevalencia de infección por este virus disminuyendo los costes con respecto al análisis individualizado de sueros, tanto en términos económicos como de manipulación de muestras (AU)

Introduction. The current number of Human Immunodeficiency Virus (HIV) infected people is not known in Spain as there is no national registry. This study has aimed to estimate the prevalence of HIV infection in the population treated in a hospital emergency department (ER) as an epidemic and risk of exposure indicator during healthcare activity and to assess the differences observed regarding previous estimates. Material and methods. We conducted a cross-sectional study of all the sera received in the ER anonymously. The final size of the pools was 5 sera. HIV antibody screening was performed using the 4th generation ELFA technique and confirmation was performed by Western Blot. Results. Seven out of the 270 pools made from 1,347 sera obtained were reactive. The individualized analysis confirmed 6 sera to be positive and 1 serum to be false positive. The observed prevalence was 0.52% (95% CI 0.10-0.94). Prevalence fell 0.87% in comparison to the years 1990-1991, although this was not statistically significant (p = 0.08).Discussion. The implementation of HIV antibodies detection through a system of pooled batches in samples collected in the ER make it possible to assess the prevalence of infection with this virus, decreasing costs with regard to individualized analysis of sera in both economic terms as well as samples handling (AU)