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Abstract(s)
O Citomegalovirus Humano (HCMV) é a causa mais frequente de infecção congénita infectando 1% (0,2% - 3%) de todos os recém-nascidos. Apesar de 90% das crianças infectadas congenitamente pelo HCMV não possuírem sinais clínicos ou sintomas à nascença, o diagnóstico desta infecção é importante uma vez que 5 a 15% das crianças com infecção congénita assintomática irá desenvolver sequelas neurológicas mais tarde, e 10% nascem com sintomas graves que no entanto não são exclusivos de uma infecção por HCMV, devendo a sua etiologia ser esclarecida. O método de referência para o diagnóstico de infecção congénita pelo HCMV nos recém-nascidos é a cultura celular. No entanto, este método apresenta algumas limitações, que podem reduzir significativamente a sensibilidade da técnica.
Assim, este trabalho teve como objectivo estudar a possibilidade de aplicar um método de nested PCR ao diagnóstico de infecção congénita por HCMV, utilizando amostras de urina colhidas em papel de filtro, para tal 273 amostras foram obtidas a partir de recém-nascidos entre a 1ª e a 3ª semana de vida. O diagnóstico de infecção congénita por HCMV foi demonstrado pela cultura celular. Das 273 amostras de urina colhidas em sacos, dezoito (7%) foram positivas para o HCMV e 255 foram negativas. As 18 urinas positivas e 100 negativas foram aplicadas em papel de filtro e testadas por nested PCR, tendo-se verificado uma correlação total entre o método de referência e o método em estudo. Assim, a pesquisa do DNA do HCMV em urina colocada em papel de filtro revelou uma sensibilidade e especificidade de 100% em comparação com a cultura celular. Como se verificou uma correlação total dos resultados, testou-se um total de 155 urinas, colhidas em papel filtro colocado directamente nas fraldas de recém-nascidos. De todas as urinas testadas não foi possível confirmar a detecção de nenhum positivo uma vez que não se obteve nenhum, no entanto não se detectou nenhum falso positivo.
Os resultados sugerem que o método é um teste confiável para o diagnóstico de infecção congénita por citomegalovírus, quando utilizado em amostras de urina colhidas nas três primeiras semanas de vida. Assim, este procedimento poderá constituir uma alternativa prática, rápida e económica ao método de cultura celular, podendo as amostras serem facilmente transportadas e guardadas à temperatura ambiente.
The human cytomegalovirus (HCMV) is the most frequent cause of congenital infection, and infect 1% (0.2% - 3%) of all newborns. Although 90% of the HCMV congenitally infected children have no clinical signs or symptoms at birth, the diagnosis of this infection is important because 5 to 15% of children with asymptomatic congenital infection will develop neurological sequelae later, and 10% born with severe symptoms that, however are not exclusive of a HCMV infection, its etiology should be clarified. The reference method for the diagnosis of congenital HCMV infection in newborns is the cell culture. However, this method has some limitations, which can significantly reduce the sensitivity of the technique. So, this work aimed to study the possibility of applying a nested PCR method for the diagnosis of congenital infection by HCMV, using samples of urine collected on filter paper. For this, were obtained 273 samples of urine from newborns between 1ª to 3ª weeks of life. A diagnosis of congenital HCMV infection was established by cell culture. Of the 273 urine samples collected into bags, eighteen (7%) were positive for HCMV and 255 were negative. The 18 positive and 100 negative urine were applied on filter paper and tested by nested PCR method and it was found a total correlation between the reference method and the method of study. Thus, the search of HCMV DNA in urine placed on filter paper revealed a sensitivity and specificity of 100% compared with cell culture. As there was a total correlation of results, it was tested a total of 155 urine, collected on filter paper placed directly on the diapers of newborns. Of all urine tested was not possible to confirm the detection of positive since it is not got none, however not detect any false positive. The results suggest that method is a reliable assay for diagnosing congenital cytomegalovirus infection when used in urines samples collected in the first three weeks of life. Thus, this procedure will be able to constitute a practical, inexpensive and easy alternative to the cell culture method for congenital infection diagnosis, principally if the samples need long transport, and make possible the samples transport and storage at room temperature.
The human cytomegalovirus (HCMV) is the most frequent cause of congenital infection, and infect 1% (0.2% - 3%) of all newborns. Although 90% of the HCMV congenitally infected children have no clinical signs or symptoms at birth, the diagnosis of this infection is important because 5 to 15% of children with asymptomatic congenital infection will develop neurological sequelae later, and 10% born with severe symptoms that, however are not exclusive of a HCMV infection, its etiology should be clarified. The reference method for the diagnosis of congenital HCMV infection in newborns is the cell culture. However, this method has some limitations, which can significantly reduce the sensitivity of the technique. So, this work aimed to study the possibility of applying a nested PCR method for the diagnosis of congenital infection by HCMV, using samples of urine collected on filter paper. For this, were obtained 273 samples of urine from newborns between 1ª to 3ª weeks of life. A diagnosis of congenital HCMV infection was established by cell culture. Of the 273 urine samples collected into bags, eighteen (7%) were positive for HCMV and 255 were negative. The 18 positive and 100 negative urine were applied on filter paper and tested by nested PCR method and it was found a total correlation between the reference method and the method of study. Thus, the search of HCMV DNA in urine placed on filter paper revealed a sensitivity and specificity of 100% compared with cell culture. As there was a total correlation of results, it was tested a total of 155 urine, collected on filter paper placed directly on the diapers of newborns. Of all urine tested was not possible to confirm the detection of positive since it is not got none, however not detect any false positive. The results suggest that method is a reliable assay for diagnosing congenital cytomegalovirus infection when used in urines samples collected in the first three weeks of life. Thus, this procedure will be able to constitute a practical, inexpensive and easy alternative to the cell culture method for congenital infection diagnosis, principally if the samples need long transport, and make possible the samples transport and storage at room temperature.
Description
Keywords
Citomégalovirus
Citation
Publisher
Universidade da Beira Interior