RESUMEN
Human respiratory syncytial virus (HRSV) strains were isolated from nasopharyngeal aspirates collected from 965 children between 2004 and 2005, yielding 424 positive samples. We sequenced the small hydrophobic protein (SH) gene of 117 strains and compared them with other viruses identified worldwide. Phylogenetic analysis showed a low genetic variability among the isolates but allowed us to classify the viruses into different genotypes for both groups, HRSVA and HRSVB. It is also shown that the novel BA-like genotype was well segregated from the others, indicating that the mutations are not limited to the G gene.
Asunto(s)
Polimorfismo Genético , Infecciones por Virus Sincitial Respiratorio/epidemiología , Infecciones por Virus Sincitial Respiratorio/virología , Virus Sincitial Respiratorio Humano/clasificación , Virus Sincitial Respiratorio Humano/genética , Proteínas Oncogénicas de Retroviridae/genética , Preescolar , Análisis por Conglomerados , Genotipo , Humanos , Lactante , Epidemiología Molecular , Datos de Secuencia Molecular , Nasofaringe/virología , Filogenia , ARN Viral/genética , Virus Sincitial Respiratorio Humano/aislamiento & purificación , Análisis de Secuencia de ADN , Homología de Secuencia de AminoácidoRESUMEN
Human respiratory syncytial virus (HRSV) is the main cause of acute lower respiratory tract infections in infants and children. Rapid diagnosis is required to permit appropriate care and treatment and to avoid unnecessary antibiotic use. Reverse transcriptase (RT-PCR) and indirect immunofluorescence assay (IFA) methods have been considered important tools for virus detection due to their high sensitivity and specificity. In order to maximize use-simplicity and minimize the risk of sample cross-contamination inherent in two-step techniques, a RT-PCR method using only a single tube to detect HRSV in clinical samples was developed. Nasopharyngeal aspirates from 226 patients with acute respiratory illness, ranging from infants to 5 years old, were collected at the University Hospital of the University of Sao Paulo (HU-USP), and tested using IFA, one-step RT-PCR, and semi-nested RT-PCR. One hundred and two (45.1%) samples were positive by at least one of the three methods, and 75 (33.2%) were positive by all methods: 92 (40.7%) were positive by one-step RT-PCR, 84 (37.2%) by IFA, and 96 (42.5%) by the semi-nested RT-PCR technique. One-step RT-PCR was shown to be fast, sensitive, and specific for RSV diagnosis, without the added inconvenience and risk of false positive results associated with semi-nested PCR. The combined use of these two methods enhances HRSV detection.
Asunto(s)
Infecciones por Virus Sincitial Respiratorio/diagnóstico , Virus Sincitial Respiratorio Humano/aislamiento & purificación , Infecciones del Sistema Respiratorio/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Preescolar , Humanos , Lactante , Recién Nacido , Faringe/virología , Infecciones por Virus Sincitial Respiratorio/virología , Virus Sincitial Respiratorio Humano/genética , Sensibilidad y EspecificidadRESUMEN
One-step reverse transcriptase polymerase chain reaction for the diagnosis of respiratory syncytial virus in children
Asunto(s)
Humanos , Niño , Diagnóstico , Sensibilidad y Especificidad , Técnicas y Procedimientos Diagnósticos , Virus Sincitiales Respiratorios , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
The Human Respiratory Syncytial Virus (HRSV), isolated in 1955, is the main cause of hospitalization of babies and infants with respiratory illness. Several studies have been conducted worldwide aiming the development of a safe and effective vaccine against HRSV. The G2 region of glycoprotein G is used as genotyping default. In the present study, we performed a phylogenetic analysis of G protein and a comparative study between G2 region and ectodomain of attachment glycoprotein. Fifty-three nasal swab samples from children less than 5 years old and presenting symptoms of acute respiratory illness, assisted at the University Hospital (UH) of University of Sao Paulo (USP) in 2004, were submitted to sequencing by PCR and compared with GenBank sequences. We concluded that the G2 region is adequate for HRSV genotyping.
O vírus respiratório sincicial humano (HRSV), isolado em 1955, é a principal causa da hospitalização de bebês e crianças pequenas com sintomas de doença respiratória. No mundo inteiro, vários estudos para o desenvolvimento de uma vacina segura e eficiente contra o HRSV têm tido alta prioridade. A região G2 da glicoproteína G é usada como padrão para genotipagem do HRSV. Neste estudo, foi realizada a análise filogenética da glicoproteína G e o estudo comparativo entre a região G2 e o ectodomínio dessa glicoproteína. Cinquenta e três amostras de swab nasal de crianças com menos de cinco anos de idade, apresentando doença respiratória aguda, atendidas no Hospital Universitário (HU) da Universidade de São Paulo durante o ano de 2004, foram submetidas a sequenciamento por PCR e comparadas com seqüências do GenBank. A região G2 mostrou ser adequada para a genotipagem do HRSV.
