Development and evaluation of a single-tube nested PCR with colorimetric assay for Mycobacterium tuberculosis detection.

Molecular techniques have revolutionized tuberculosis (TB) diagnosis by offering a faster and more sensitive approach, detecting Mycobacterium tuberculosis (Mtb) DNA directly from samples. Single-tube nested PCR (STNPCR) combines two PCR reactions with separate oligonucleotide sets in a single tube. Moreover, colorimetric methods in PCR products have been studied for pathogen detection. Thus, this study aimed to establish a novel system based on colorimetric STNPCR for Mtb detection using microtiter plates with IS6110-amplified fragments. The results showed a general colorimetric STNPCR detection limit of 1 pg/µl. Its general sensitivity and specificity were 76.62 and 60.53%, respectively, with kappa index agreement of 0.166.

Rapid detection of Mycobacterium tuberculosis in children using blood and urine specimens.

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.

Rapid detection of Mycobacterium tuberculosis in children using blood and urine specimens

Abstract 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.

Osteoarticular tuberculosis in an HIV-positive patient: a case report.

The authors report a case of a 38-year-old HIV-positive woman, with subcutaneous nodules on the thoracic region with 3 months of evolution. Clinical, laboratory, and epidemiological features were evaluated and associated with apparent damage to the T11-T12 vertebrae, identification by imaging tests, positivity in a polymerase chain reaction-based test, and reactivity to the Mantoux tuberculin skin test (PPD-RT 23). The patient was diagnosed with osteoarticular tuberculosis and received treatment for a year, and clinical cure was achieved.

Osteoarticular tuberculosis in an HIV-positive patient: a case report

The authors report a case of a 38-year-old HIV-positive woman, with subcutaneous nodules on the thoracic region with 3 months of evolution. Clinical, laboratory, and epidemiological features were evaluated and associated with apparent damage to the T11-T12 vertebrae, identification by imaging tests, positivity in a polymerase chain reaction-based test, and reactivity to the Mantoux tuberculin skin test (PPD-RT 23). The patient was diagnosed with osteoarticular tuberculosis and received treatment for a year, and clinical cure was achieved.