RESUMO
BACKGROUND: Although the genome of severe acute respiratory syndrome coronavirus (SARS-CoV) has been sequenced and a possible animal reservoir identified, seroprevalence studies and mass screening for detection of subclinical and non-pneumonic infections are still lacking. METHODS: We cloned and purified the nucleocapsid protein and spike polypeptide of SARS-CoV and examined their immunogenicity with serum from patients with SARS-CoV pneumonia. An ELISA based on recombinant nucleocapsid protein for IgG detection was tested with serum from 149 healthy blood donors who donated 3 years previously and with serum positive for antibodies against SARS-CoV (by indirect immunofluorescence assay) from 106 patients with SARS-CoV pneumonia. The seroprevalence of SARS-CoV was studied with the ELISA in healthy blood donors who donated during the SARS outbreak in Hong Kong, non-pneumonic hospital inpatients, and symptom-free health-care workers. All positive samples were confirmed by two separate western-blot assays (with recombinant nucleocapsid protein and recombinant spike polypeptide). FINDINGS: Western-blot analysis showed that the nucleocapsid protein and spike polypeptide of SARS-CoV are highly immunogenic. The specificity of the IgG antibody test (ELISA with positive samples confirmed by the two western-blot assays) was 100%, and the sensitivity was 94.3%. Three of 400 healthy blood donors who donated during the SARS outbreak and one of 131 non-pneumonic paediatric inpatients were positive for IgG antibodies, confirmed by the two western-blot assays (total, 0.48% of our study population). INTERPRETATION: Our findings support the existence of subclinical or non-pneumonic SARS-CoV infections. Such infections are more common than SARS-CoV pneumonia in our locality.
Assuntos
Coronavirus/isolamento & purificação , Pneumonia Viral/epidemiologia , Síndrome Respiratória Aguda Grave/epidemiologia , Doadores de Sangue , Western Blotting , China/epidemiologia , Coronavirus/genética , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/imunologia , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina G/análise , Imunoglobulina G/imunologia , Glicoproteínas de Membrana/análise , Proteínas do Nucleocapsídeo/genética , Proteínas do Nucleocapsídeo/imunologia , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Proteínas Recombinantes/análise , Proteínas Recombinantes/imunologia , Estudos Soroepidemiológicos , Síndrome Respiratória Aguda Grave/imunologia , Síndrome Respiratória Aguda Grave/virologia , Glicoproteína da Espícula de Coronavírus , Proteínas do Envelope Viral/análiseRESUMO
We describe the application of 16S rRNA gene sequencing in defining eight cases of bacteremia due to Haemophilus species other than Haemophilus influenzae (non-H. influenzae bacteremia) during a 7-year period. The first case of acute pyelonephritis due to Haemophilus segnis is also reported. In contrast to the extremely rare incidence of H. segnis infections reported previously, our results suggested that H. segnis is an important cause of non-H. influenzae bacteremia.
Assuntos
Bacteriemia/microbiologia , DNA Ribossômico/genética , Inativação Gênica , Genes Bacterianos/genética , Infecções por Haemophilus/microbiologia , Haemophilus/classificação , RNA Ribossômico 16S/genética , Bacteriemia/diagnóstico , Haemophilus/genética , Haemophilus/isolamento & purificação , Humanos , Dados de Sequência Molecular , FilogeniaRESUMO
We report the evaluation of recombinant severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) nucleocapsid protein enzyme-linked immunosorbent assay (ELISA)-based antibody tests for serodiagnosis of SARS-CoV pneumonia and compare the sensitivities and specificities of this ELISA for detection of immunoglobulin G (IgG), IgM, IgA, and their combinations with serum samples from 149 healthy blood donors who donated blood 3 years ago as controls and 106 SARS-CoV pneumonia patients in Hong Kong. The specificities of the ELISA for IgG, IgM, and IgA detection were 95.3, 96.6, and 96.6%, respectively, with corresponding sensitivities of 94.3, 59.4, and 60.4%, respectively. The present ELISA appears to be a sensitive test for serodiagnosis of SARS-CoV pneumonia, is much more economical and less labor-intensive than the indirect immunofluorescence assay, and does not require cultivation of SARS-CoV.