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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 effi cient diagnostic tests that combine high sensitivity and specifi city 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 specifi city 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.

Aim: Evaluate the IS6110-Taqman system performance in sputum samples from patients with pulmonary tuberculosis from health services in northeastern Brazil as a diagnostic laboratory tool for pulmonary tuberculosis. Methods and Results: 165 sputum samples from respiratory symptomatic patients were evaluated in the IS6110-TaqMan assay: 66 patients with pulmonary tuberculosis and 99 without TB. When the IS6110-TaqMan assay was evaluated using culture and/or clinical response to the specific treatment as the gold standard, IS6110-TaqMan assay obtained a sensitivity of 87Á9% and specificity of 98%. The performance of IS6110-TaqMan assay was also evaluated with the sputum smear microscopy, resulting in a sensitivity of 79Á7% and specificity 94Á8%. Conclusions: The IS6110-TaqMan was rapid, sensitive and specific for the diagnosis of pulmonary TB. Significance and Impact of the Study: IS6110-TaqMan assay is a promising auxiliary tool for the diagnosis of pulmonary TB when used in conjunction with routine laboratory tests, clinical and epidemiological criteria of the patient, thus increasing the sensitivity and specificity of diagnosis.

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.

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.

Aims: To analyse the performance of RT-qPCR using 85B mRNA in the diagnosis of Mycobacterium tuberculosis infection and in the assessment of the response to treatment for pulmonary tuberculosis (TB). Methods and Results: Ninety-eight patients with signs of pulmonary TB were selected: 56 were considered infected with Myco. tuberculosis and they had positive cultures or evident clinical response to anti-TB treatment. Patients with pulmonary tuberculosis were evaluated by culture and RT-qPCR for a 30-day specific treatment. It was found that both tests demonstrated a decline in viable bacilli at 15 and 30 days after the beginning of the therapy in most of the patients. The quantification of the 85B mRNA target was performed in 52 patients who had initially shown positive results by RT-qPCR and who were followed on the days 15 and 30 after the specific treatment. Thus 85B mRNA was detectable in sputum samples in 52 patients with a confirmed diagnosis of pulmonary tuberculosis on day 0. During the specific treatment the 85B mRNA was detectable in 13 patients on day 15 and in only three patients on day 30. Conclusions: Mycobacterium tuberculosis mRNA in the sputum is a useful prognostic marker and its quantification, an early and reliable indicator for monitoring response to treatment, drug resistance, re-infection and relapse. Significance and Impact of the Study: RT-qPCR is a tool that can be used in clinical and therapeutic monitoring as an indicator of bacterial resistance and indicator of the period of transmissibility of Myco. tuberculosis in patients with pulmonary TB undergoing treatment.

Introduction: Laboratory and clinical features of childhood tuberculosis (TB) are non-specific and establishing an accurate diagnosis remains a challenge. This study evaluated a Single tube nested-PCR (STNPCR) to detect genomic DNA of Mycobacterium tuberculosis complex in blood and urine. Methods: Biological samples were obtained from children (<15 years old) with clinical suspicion of pulmonary and extrapulmonary TB at public hospitals in Recife-Pernambuco, Brazil. Cultures yielded negative results in a majority of childhood TB cases, which are generally paucibacillary. A set of clinical, epidemiological, radiological, and laboratory criteria with evident clinical improvement after anti-TB treatment were frequently used to define childhood TB cases. Results: Ninety children with clinical suspicion were enrolled in this study (44 with TB and 46 without TB). The pulmonary TB group had 20 confirmed cases and 46 negative controls, while the extrapulmonary TB group had 24 confirmed cases. The STNPCR showed sensitivities to pulmonary and extrapulmonary TB of 47.4% and 52.2% (blood) and 38.8% and 20% (urine), respectively. Considering the low performance of STNPCR on separate samples, we decided to perform a combined analysis (parallel sensitivity analysis) of the results from blood and urine samples. The parallel sensitivity increased to 65% in blood and 62.5% in urine. The specificity in both samples ranged from 93.5-97.8%. Conclusions: Although STNPCR showed moderate sensitivity, the specificity is high; therefore, the test can be used as an auxiliary tool to diagnose TB in children. It is a rapid test that demonstrated better performance than other diagnostic tests in paucibacillary samples as it does in childhood tuberculosis.

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