ABSTRACT
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Subject(s)
Humans , Metapneumovirus , Paramyxoviridae Infections/diagnosis , Virology/methodsABSTRACT
Introducción: El metapneumovirus humano (hMPV) es el causante de un número importante de infecciones en pediatría, entre un 14 y un 22% de las infecciones respiratorias víricas con diagnóstico etiológico establecido. Se presenta un estudio comparativo entre una técnica de inmunofluorescencia directa (IFD), una de enzimoinmunoanálisis (EIA) y el cultivo según la técnica de shell vial. Métodos: Se procesaron 124 aspirados nasofaríngeos pertenecientes a 108 lactantes con infecciones respiratorias de vías bajas. Durante su recepción se los procesó para la IFD, para lo que se utilizó un anticuerpo anti-hMPV comercial (Diagnostic Hybrids Inc.) y se sembró en la línea celular LLC-MK2 (sólo 76 muestras) para fijarse y teñirse a las 48h con el mismo suero citado. El resto de la muestra se procesó según la rutina diagnóstica habitual y se congeló en alícuotas para posterior estudio con EIA (Biotrin®).Resultados: Veinte muestras (16,12%) fueron positivas al hMPV mediante la IFD, 27 muestras (21,77%) fueron positivas mediante el EIA y 15 muestras (19,73%) fueron positivas mediante cultivo. La IFD y el EIA coincidieron en un 92,73% de las 124 muestras. Al considerar las 3 pruebas (76 muestras) se consiguió una concordancia del 90,78%. Al considerar sólo las primeras muestras de cada enfermo (fase aguda), la sensibilidad, los valores predictivos y el índice Kappa de la IFD mejoraron y se acercaron a los obtenidos con el EIA. Conclusión: Ambas pruebas de detección de antígeno son útiles en el diagnóstico de la infección aguda por hMPV en aquellos hospitales pediátricos que no dispongan de las técnicas de amplificación para este virus y necesiten un diagnóstico etiológico con urgencia, con la salvedad de que la IFD está indicada sólo en la fase inicial de la infección (AU)
Introduction: Human metapneumovirus (hMPV) is an important cause of lower respiratory tract infections in children, accounting for 14% to 24% of all viral respiratory infections with an etiological diagnosis. This study compares a direct fluorescent antibody (DFA) test, enzyme immunoassay (EIA), and shell-vial culture for diagnosing acute bronchiolitis in infants.Methods: A total of 124 nasopharyngeal aspirates from 108 infants with lower respiratory tract infection were analyzed. Incoming samples were processed for DFA using a commercial anti-hMPV antibody (Diagnostic Hybrids Inc.®); 76 were inoculated in an LLC-MK2 cell line, and after an incubation period of 48h, were stained and fixed with the aforementioned serum. The remaining sample was processed according to the routine diagnostic procedure and aliquots were frozen for EIA analysis (Biotrin®).Results: Twenty (16.12%) samples were positive for hMPV by DFA, 27 (21.77%) by EIA, and 15 (19.73%) by culture. DFA and EIA results were consistent in 92.73% of the 124 samples. Considering the 3 techniques, the same results were obtained in 90.78% of the 76 specimens. Considering only the first specimen from each patient (acute phase), the sensitivity, predictive values, and Kappa index for DFA improved and were very close to the EIA values.Conclusion: DFA and EIA are useful for antigen detection in the diagnosis of acute hMPV infection, particularly in pediatric hospitals that do not have amplification techniques for this virus, and when a rapid diagnosis is required. It should be kept in mind that DFA analysis is a suitable test for this purpose only in the acute phase of the infection (AU)
Subject(s)
Humans , Metapneumovirus/isolation & purification , Paramyxoviridae Infections/microbiology , Respiratory Tract Infections/microbiology , Metapneumovirus/pathogenicity , Fluorescent Antibody Technique, Direct/methods , Immunoenzyme Techniques/methods , Culture Techniques/methods , Nasopharynx/microbiologyABSTRACT
INTRODUCTION: Human metapneumovirus (hMPV) is an important cause of lower respiratory tract infections in children, accounting for 14% to 24% of all viral respiratory infections with an etiological diagnosis. This study compares a direct fluorescent antibody (DFA) test, enzyme immunoassay (EIA), and shell-vial culture for diagnosing acute bronchiolitis in infants. METHODS: A total of 124 nasopharyngeal aspirates from 108 infants with lower respiratory tract infection were analyzed. Incoming samples were processed for DFA using a commercial anti-hMPV antibody (Diagnostic Hybrids Inc.); 76 were inoculated in an LLC-MK2 cell line, and after an incubation period of 48 h, were stained and fixed with the aforementioned serum. The remaining sample was processed according to the routine diagnostic procedure and aliquots were frozen for EIA analysis (Biotrin). RESULTS: Twenty (16.12%) samples were positive for hMPV by DFA, 27 (21.77%) by EIA, and 15 (19.73%) by culture. DFA and EIA results were consistent in 92.73% of the 124 samples. Considering the 3 techniques, the same results were obtained in 90.78% of the 76 specimens. Considering only the first specimen from each patient (acute phase), the sensitivity, predictive values, and Kappa index for DFA improved and were very close to the EIA values. CONCLUSION: DFA and EIA are useful for antigen detection in the diagnosis of acute hMPV infection, particularly in pediatric hospitals that do not have amplification techniques for this virus, and when a rapid diagnosis is required. It should be kept in mind that DFA analysis is a suitable test for this purpose only in the acute phase of the infection.
