Molecular Detection of Mycobacterium Tuberculosis Complex from Sputum of Clinically Suspected Tuberculosis Cases

ABSTRACT

Background: Tuberculosis (TB) is a communicable disease and it  ranks second of all infectious agents due to co-infection with HIV . The causative agent of tuberculosis is a group of mycobacteria known as Mycobacterium tuberculosis complex. Mycobacterium tuberculosis complex consist of M. tuberculosis, M. bovis, M. africanum, M. microti, M. canetti. In PCR study, Most commonly sensitivity is higher in smear positive samples (95-100%) rather than smear negative specimens (46-63%). OBJECTIVE: To detection of Mycobacterium tuberculosis complex by Line Probe Assay. Methods: The study was done from non-interventional approaching study of 50 suspected patients of tuberculosis had visited the TB chest/ DOTS centre. Sputum sample collected early morning in a wide- mouth container from the patients having history of cough more than 2 weeks. Methodology used Z-N staining and for detection of MTB complex was done using MTBDR plus assay, multiplex PCR DNA strip assay (Hain Lifescience, Nehren, Gernamy) which is commercially available. M. tuberculosis secreted an important protein is MPT64, a 24-kDa protein. The major culture filtrate protein (24-kDa) is MPT64 encoded by the RD2 region genes and has been exposed to be an exact antigen that differentiates the M. tuberculosis complex from the mycobacteria other than tuberculosis (MOTT) Species. Results: In 50 samples, out of which 10 (20%) were smear positive & 40(80%) were smear negative. Out of 10 smear positive, 9 (90%) were MTB (Mycobacterium tuberculosis) & 01 (10%) was NTM (Non-tuberculous Mycobacteria) by PCR method. Out of 40 smear negative, 30 (75%) were positive by PCR method. Out of 30, 28(93%) were MTB & 02(7%) were NTM. Rests of the 10(25%) samples were found negative for M. tuberculosis complex. Conclusions: This study proved that PCR is a specific and sensitive method in comparison of sputum microscopy after staining with Z-N technique and it helpful  the clinicians ability to diagnose and treat the patients on time. This will ensure early treat to patients and prevent further transmission of disease.