Genetic heterogeneity revealed by sequence analysis of Mycobacterium tuberculosis isolates from extra-pulmonary tuberculosis patients

Abstract Background Rapid and accurate diagnosis of extra-pulmonary tuberculosis (EPTB) is imperative for early treatment and better patient outcome. Loop-mediated Isothermal Amplification (LAMP) is a promising nucleic-acid amplification assay. LAMP assay could be carried out in simple water bath under isothermal conditions in 60 minutes, and can be performed in any laboratory even in rural setting in resource poor endemic countries. We evaluated LAMP assay using two different target regions LAMP primers specific for Mycobacterium tuberculosis complex for the diagnosis of EPTB. Methods LAMP assay using 6 primers (each for IS6110 and IS1081) specific for Mycobacterium tuberculosis complex were performed on patients suspected of EPTB on various EPTB samples(CSF, Synovial fluid, Lymaphnode and tissue biopsies and various other samples) of 150 patients (50 confirmed, 100 suspected) Clinically suspected of EPTB and 100 non-TB control subjects. Results Overall LAMP test (using any of the two targets) had sensitivity and specificity of 96% and 100% for confirmed (50 culture positive) EPTB cases. In 100 clinically suspected but unconfirmed EPTB cases, LAMP was positive in 87 out of 100 cases (87%). Sensitivity of IS6110 LAMP, 1S1081 LAMP and IS6110 PCR for clinically suspected cases was 78 (78%), 84 (84%) and 70 (70%), respectively. In total 150 EPTB patients, the overall sensitivity of microscopy, culture, IS6110 PCR, IS6110 LAMP, 1081 LAMP and the LAMP test (if any of the two targets were used) were 4%, 33.3%, 74.6%, 82.66%, 87% and 92%, respectively. Specificity of all the tests was 100%. There were 8 cases which were missed by IS6110 LAMP and 2 cases by 1081 LAMP. Conclusion LAMP assay using two targets is a promising technique for rapid diagnosis of EPTB in 60 minutes especially in a resource poor setting who are still battling with this deadly disease. Disclosures All Authors: No reported disclosures

Download Full-text

The silent pandemic in South Africa: Extra-pulmonary tuberculosis from head to heel

South African Journal of Radiology ◽

10.4102/sajr.v25i1.2026 ◽

2021 ◽

Vol 25 (1) ◽

Author(s):

Camilla E. Le Roux ◽

Sucari S.C. Vlok

Keyword(s):

South Africa ◽

Mycobacterium Tuberculosis ◽

Pulmonary Tuberculosis ◽

Communicable Disease ◽

Diagnostic Dilemma ◽

Extra Pulmonary Tuberculosis ◽

Immunodeficiency Virus ◽

Normal Chest Radiograph ◽

Normal Chest ◽

Extra Pulmonary

Extra-pulmonary tuberculosis (EPTB), caused by Mycobacterium tuberculosis, is the leading cause of communicable disease-related deaths in people with human immunodeficiency virus (HIV) worldwide and in South Africa. Mycobacterium tuberculosis disseminates haematogenously from an active primary lung focus and may affect extra-pulmonary sites in up to 15% of patients. Extra-pulmonary TB may present with a normal chest radiograph, which often causes a significant diagnostic dilemma. This review describes the main sites of involvement in EPTB, which is illustrated by local imaging examples.

Download Full-text