Proteomic Analysis of Urine from Patients with Plasmodium vivax Malaria Unravels a Unique Plasmodium vivax Protein That Is Absent from Plasmodium falciparum.

Five species of Plasmodium cause malaria in humans and two of them, P. vivax and P. falciparum, pose the greatest threat. Rapid antigen detection tests (RADT) have been used for many years to diagnose and distinguish malaria caused by these two parasites. P. falciparum malaria can single-handedly be diagnosed using an RADT, which detects the unique P. falciparum specific histidine-rich protein 2 (HRP2). Unfortunately, there is no RADT that can single-handedly diagnose P. vivax malaria because no specific marker of this parasite has yet been described. Here, we report the discovery of a unique P. vivax protein (Vir14, NCBI Reference Sequence: XP_001612449.1) that has no sequence similarity with proteins of P. falciparum and no significant similarities with proteins of other species of Plasmodium. We propose that this protein could be an outstanding candidate molecule for the development of a promising RADT that can single-handedly and specifically diagnose P. vivax malaria.

Estudio Prospectivo Observacional: Determinar la Sensibilidad del Criterio Clínico usando la Escala de "Centor" versus el Test de Detección Rápida de Estreptococo para el diagnóstico de Faringitis Estreptocócica del Grupo A en el Centro de Salud Bárbara / Observational Prospective Study: Determine the Sensitivity of the Clinical Criteria using the "Centor" Scale versus the Rapid Streptococcal Screening Test for the diagnosis of Group A Streptococcal Pharyngitis at the Bárbara Health Center

Introducción: Las faringitis producidas por el estreptococo beta hemolítico del grupo A no se pueden distinguir clínicamente de las faringitis producidas por otros gérmenes, sin embargo la utilización de los criterios de Centor y el test de detección rápida de antígeno son de gran utilidad para determinar las probabilidades que estos sean causados por el estreptococo beta hemolítico del grupo A. En este estudio se comparó la sensibilidad entre ambos métodos. Objetivos: Se realizó un estudio para determinar la sensibilidad del criterio clínico en el diagnóstico de faringitis causada por Estreptococo en comparación a la sensibilidad del test de detección rápida de antígeno. Metodología: En el Centro de Salud Bárbara, se tomaron a los pacientes pediátricos que consultaron por dolor de garganta durante dos meses. Se puntuó según la escala de Centor y se tomó una muestra para el test de detección rápida de antígeno, luego, se comparó con el cultivo de orofaringe. Resultados: Se comparó la sensibilidad de ambos parámetros. Discusión: Un puntaje ≥ 3 puntos en la escala de Centor tuvo una sensibilidad de 81.8% y especificidad de 50%. Mientras que el RADT presentó una sensibilidad del 83.3% y especificidad de 84.2%.

Introduction: Pharyngitis caused by group A beta-hemolytic streptococci cannot be distinguished clinically from pharyngitis caused by other germs, however the use of the Centor criteria and the rapid antigen detection test are very useful to determine this pathogen. These are likely to be caused by group A beta hemolytic streptococcus. In this study the sensitivity between the two methods were compared. Objectives: A study was conducted to determine the sensitivity of clinical criteria in the diagnosis of pharyngitis caused by Streptococcus in comparison to the sensitivity of the rapid antigen detection test. Methodology: In the Barbara Health Center, pediatric patients who consulted for sore throat for two months were taken. It was scored according to the Centor scale and a sample was taken for the rapid antigen detection test, later these were compared with the oropharynx culture. Results: The sensitivity of both parameters were compared. Discussion: A score ≥ 3 points on the Centor scale had a sensitivity of 81.8% and specificity of 50%. While the RADT presented a sensitivity of 83.3% and specificity of 84.2%.

Comparison of Oropharyngeal and Nasopharyngeal Swab Specimens for the Detection of Mycoplasma pneumoniae in Children with Lower Respiratory Tract Infection.

The oropharyngeal swab specimen was superior to the nasopharyngeal swab specimen for the detection of Mycoplasma pneumoniae in children with lower respiratory tract infection. The oropharyngeal loop-mediated isothermal amplification had 100% sensitivity and specificity compared with polymerase chain reaction testing, whereas the oropharyngeal rapid antigen detection test using immunochromatographic assay had relatively low sensitivity (66%) and reasonable specificity (90.7%).

Rapid antigen detection test for respiratory syncytial virus diagnosis as a diagnostic tool / Teste rápido de detecção de antígenos para o diagnóstico do Vírus Sincicial Respiratório como ferramenta de diagnóstico

Abstract Objective: The aim of this study was to evaluate the QuickVue® RSV Test Kit (QUIDEL Corp, CA, USA) as a screening tool for respiratory syncytial virus in children with acute respiratory disease in comparison with the indirect immunofluorescence assay as gold standard. In Brazil, rapid antigen detection tests for respiratory syncytial virus are not routinely utilized as a diagnostic tool, except for the diagnosis of dengue and influenza. Methods: The authors retrospectively analyzed 486 nasopharyngeal aspirate samples from children under age 5 with acute respiratory infection, between December 2013 and August 2014, the samples were analyzed by indirect immunofluorescence assay and QuickVue® RSV Test kit. Samples with discordant results were analyzed by real time PCR and nucleotide sequencing. Results: From 313 positive samples by immunofluorescence assays, 282 (90%) were also positive by the rapid antigen detection test, two were positive only by rapid antigen detection test, 33 were positive only by immunofluorescence assays, and 171 were positive by both methods. The 35 samples with discordant results were analyzed by real time PCR; the two samples positive only by rapid antigen detection test and the five positive only by immunofluorescence assays were also positive by real time PCR. There was no relation between the negativity by QuickVue® RSV Test and viral load or specific strain. The QuickVue® RSV Test showed sensitivity of 90%, specificity of 98.8%, predictive positive value of 99.3%, and negative predictive value of 94.6%, with accuracy of 93.2% and agreement κ index of 0.85 in comparison to immunofluorescence assay. Conclusions: This study demonstrated that the QuickVue® RSV Test Kit can be effective in early detection of Respiratory syncytial virus in nasopharyngeal aspirate and is reliable for use as a diagnostic tool in pediatrics.

Resumo Objetivo: Avaliar o teste QuickVue® RSV Test Kit (QUIDEL Corp, CA, EUA) para o diagnóstico rápido do vírus sincicial respiratório em crianças com doença respiratória aguda, comparandoo com a imunofluorescência indireta como padrão ouro. Visto que, no Brasil, testes rápidos para detecção de antígenos para vírus sincicial respiratório não são rotineiramente utilizados como ferramenta de diagnóstico, exceto para Dengue e Influenza. Métodos: Um total de 486 amostras de aspirado de nasofaringe de crianças menores de 5 anos com doença respiratória aguda, coletadas entre dezembro de 2013 e agosto de 2014, foram analisadas por imunofluorescência e pelo teste QuickVue®. Amostras com resultados discordantes entre os métodos foram submetidas a PCR em tempo real e sequenciamento. Resultados: Das 313 amostras positivas por IFI, 282 foram positivas no teste rápido (90%), 2 amostras foram positivas apenas no teste rápido (0.6%), 33 apenas na imunofluorescência (10.5%) e 171 foram negativas em ambos os métodos. As 35 amostras com resultados discordantes foram testadas por PCR em tempo real, sendo que duas que foram positivas apenas no teste rápido e 5 apenas na imunofluorescência confirmaram-se positivas. Não houve relação entre a ausência de positividade no teste QuickVue® com a carga ou com a cepa viral. O teste QuickVue® mostrou sensibilidade de 90.1%, especificidade 98.9%, valor preditivo positivo 99.3%, valor preditivo negativo de 94.6%, acurácia de 93.2% e índice de concordância de 0.85 em comparação à imunofluorescência. Conclusões: Nosso estudo demonstrou que o teste QuickVue® RSV pode ser efetivo na detecção precoce do vírus sincicial respiratório em amostras de aspirado de nasofaringe e é confiável como uma ferramenta de diagnósticos em pediatria.

Rapid antigen detection test for respiratory syncytial virus diagnosis as a diagnostic tool.

OBJECTIVE: The aim of this study was to evaluate the QuickVue® RSV Test Kit (QUIDEL Corp, CA, USA) as a screening tool for respiratory syncytial virus in children with acute respiratory disease in comparison with the indirect immunofluorescence assay as gold standard. In Brazil, rapid antigen detection tests for respiratory syncytial virus are not routinely utilized as a diagnostic tool, except for the diagnosis of dengue and influenza. METHODS: The authors retrospectively analyzed 486 nasopharyngeal aspirate samples from children under age 5 with acute respiratory infection, between December 2013 and August 2014, the samples were analyzed by indirect immunofluorescence assay and QuickVue® RSV Test kit. Samples with discordant results were analyzed by real time PCR and nucleotide sequencing. RESULTS: From 313 positive samples by immunofluorescence assays, 282 (90%) were also positive by the rapid antigen detection test, two were positive only by rapid antigen detection test, 33 were positive only by immunofluorescence assays, and 171 were positive by both methods. The 35 samples with discordant results were analyzed by real time PCR; the two samples positive only by rapid antigen detection test and the five positive only by immunofluorescence assays were also positive by real time PCR. There was no relation between the negativity by QuickVue® RSV Test and viral load or specific strain. The QuickVue® RSV Test showed sensitivity of 90%, specificity of 98.8%, predictive positive value of 99.3%, and negative predictive value of 94.6%, with accuracy of 93.2% and agreement κ index of 0.85 in comparison to immunofluorescence assay. CONCLUSIONS: This study demonstrated that the QuickVue® RSV Test Kit can be effective in early detection of Respiratory syncytial virus in nasopharyngeal aspirate and is reliable for use as a diagnostic tool in pediatrics.

Asymptomatic Group A Streptococcus carriage in children with recurrent tonsillitis and tonsillar hypertrophy.

BACKGROUND: Group A Streptococcus (GAS) is the most important bacterial cause of acute tonsillitis in children. Some children are chronic GAS carriers, and this carriage is poorly understood. We determined the frequency of GAS detection using a rapid antigen detection test in pediatric patients with indications for tonsillectomy due to adenotonsillar hypertrophy or recurrent GAS infections. METHODS: Seventy-two patients underwent a tonsil swab for a rapid antigen detection test. RESULTS: The GAS rapid antigen detection test was positive in 18.1% of children. GAS was not associated with sex, age or previous history of recurrent tonsillitis. Also, the prevalence of GAS was similar between patients with either recurrent tonsillitis or tonsil hypertrophy. CONCLUSION: In our study, the GAS carriage rate was similar to other reports, and GAS carrier state was not correlated with recurrent tonsillitis.

Host and viral factors affecting clinical performance of a rapid diagnostic test for respiratory syncytial virus in hospitalized children.

Respiratory syncytial virus rapid antigen detection tests (RADT) are used widely. RADT exhibited high specificity (97%) and moderate sensitivity (80%) compared with reverse-transcriptase polymerase chain reaction in 720 hospitalized children <3 years old. Older age, prolonged symptoms, and respiratory syncytial virus genotype-B infection were significantly associated with false-negative results of RADT.