Evaluation of Methods for Extracting DNA of Mycobacterium Tuberculosis from Sputum Specimens and Bronchial Washing Fluids

Tuberculosis is one of the most infectious diseases causing high death rates and serious public health impact. Common TB diagnostic methods such as chest X-ray, sputum smear and culture have limited sensitivity, specificity, and time-consuming compared with molecular biology techniques. In this study, five methods of DNA extraction of Mycobacterium tuberculosis (MTB) from 25 AFB-positive sputum samples and 25 bronchial washing fluid samples were compared and evaluated the extraction efficiency. The DNA products were then performed to a polymerase chain reaction (PCR) to amplify the IS6110 and 16S rRNA genes. The results have successfully optimized the DNA extraction method of MTB by 2ndmethod, it’s using Lysis buffer (including: Tris-HCl 1M, pH 8.5; EDTA 0.5M; SDS 10%; and NaCl 5M). The obtained DNA product has high purity and integrity and the PCR reaction was successfully performed. This result creates a premise for building a real-time 16S rRNA test procedure in the diagnosis of pulmonary tuberculosis in a few medical facilities in Hanoi.