RESUMEN
Abstract INTRODUCTION: This study evaluated the performance of the IS6110-TaqMan® assay in different types of biological samples and tissues for laboratory diagnosis of extrapulmonary tuberculosis. METHODS: 143 biological samples and tissues from patients with suspected extrapulmonary tuberculosis from the health services of Recife/Pernambuco/Brazil were evaluated with the IS6110-TaqMan® assay. RESULTS: The sensitivities of the IS6110-TaqMan® assay calculated for blood, urine, both blood and urine samples, tissue biopsies, extrapulmonary body fluid samples, and all samples from patients calculated together were 55.9%, 33.3%, 68.8%, 43.8%, 29.6%, and 73.7%, respectively, and the specificities were 80%, 100%, 78.6%, 100%, 100%, and 84.2%, respectively. CONCLUSIONS The accuracy of qPCR was high in various clinical sample types. The analysis of more than one type of clinical sample collected from the same patient with extrapulmonary tuberculosis enhances the diagnostic power of the IS6110-TaqMan® assay when compared with the use of only one clinical sample.
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Humanos , Tuberculosis/diagnóstico , ADN Bacteriano/análisis , Mycobacterium tuberculosis/genética , ADN Bacteriano/aislamiento & purificación , ADN Bacteriano/genética , Método Doble Ciego , Estudios Prospectivos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Reacción en Cadena en Tiempo Real de la Polimerasa , Mycobacterium tuberculosis/aislamiento & purificaciónRESUMEN
Abstract: INTRODUCTION : Molecular analyses are auxiliary tools for detecting Koch's bacilli in clinical specimens from patients with suspected tuberculosis (TB). However, there are still no efficient diagnostic tests that combine high sensitivity and specificity and yield rapid results in the detection of TB. This study evaluated single-tube nested polymerase chain reaction (STNPCR) as a molecular diagnostic test with low risk of cross contamination for detecting Mycobacterium tuberculosis in clinical samples. METHODS: Mycobacterium tuberculosis deoxyribonucleic acid (DNA) was detected in blood and urine samples by STNPCR followed by agarose gel electrophoresis. In this system, reaction tubes were not opened between the two stages of PCR (simple and nested). RESULTS: STNPCR demonstrated good accuracy in clinical samples with no cross contamination between microtubes. Sensitivity in blood and urine, analyzed in parallel, was 35%-62% for pulmonary and 41%-72% for extrapulmonary TB. The specificity of STNPCR was 100% in most analyses, depending on the type of clinical sample (blood or urine) and clinical form of disease (pulmonary or extrapulmonary). CONCLUSIONS: STNPCR was effective in detecting TB, especially the extrapulmonary form for which sensitivity was higher, and had the advantage of less invasive sample collection from patients for whom a spontaneous sputum sample was unavailable. With low risk of cross contamination, the STNPCR can be used as an adjunct to conventional methods for diagnosing TB.
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Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , ADN Bacteriano , Mycobacterium tuberculosis/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Tuberculosis/diagnóstico , ADN Bacteriano/sangre , ADN Bacteriano/orina , Mycobacterium tuberculosis/genética , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
The authors report a case of a 12-year-old child with a complaint of pain and deformity in the lower thoracic region that had lasted for two years. Clinical, epidemiological and laboratory characteristics associated with images of apparent damage in the T9-T10 and T11-T12 vertebrae taken by radiography of the thoracic spine and nuclear magnetic resonance in addition to the positivity of the molecular test based on the polymerase chain reaction, led to tuberculous spondylitis being diagnosed and specific therapy was started. Culture of vertebral biopsy was positive for Mycobacterium tuberculosis after thirty days.