Abstract

MDR EXTRA-PULMONARY TUBERCULOSIS: DIAGNOSTIC AND COMPARATIVE EVALUATION OF CONVENTIONAL VS. AUTOMATED TECHNIQUES

Dr. Preeti Chaudhary*, Dr. Digvijay Singh, Dr. Anil Kanga and Dr. Aneeta Kumari

ABSTRACT

Introduction: Early diagnosis of tuberculosis is an essential step in treating, curing and preventing deaths due to tuberculosis. Non-specific presentation and paucibacillary load in extra-pulmonary tuberculosis (EPTB) results in under-diagnoses leading to under treatment. This necessitates need for diagnostics which can facilitate its early and correct diagnosis. Methodology: We did comparative evaluation in extra-pulmonary samples by microscopy, conventional culture and liquid culture using mycobacterial growth indicator tube (MGIT-960). Positive cultures were differentiated as to Mycobacterium tuberculosis complex (MTBc) or non-tubercular mycobacterium (NTM) by immunochromatography assay using MPT-64 antigen. Further it was followed by drug susceptibility testing of MTBc isolates thereby identifying multi-drug resistant strains. Results: Out of 581 samples, 134 strains were isolated on MGIT-960 with 97.1% positivity and the detection time was 11 days. On Lowenstein-Jensen medium 68 strains were isolated with 49.3% positivity and detection time was 35 days. Sensitivity of the liquid media was more than the Lowenstein-Jensen medium. The rate of contamination was more in liquid medium as compared to solid medium. Mycobacterium complex isolates were 88 and Non tubercular mycobacteria were 50. Among Mycobacterium tuberculosis complex isolates 47 were sensitive to all the drugs and 41 were resistant to one or more drugs. Multiple drug resistant (MDR) isolates were 12 i.e. 13.6%. Conclusion: MDR-TB is gradually increasing in EPTB due to improper diagnosis and inadequate treatment. Differentiating mycobacterium as MTBc and NTM supported by sensitivity testing by using liquid culture has proved to be helpful in early decision for chemotherapy in MDR-EPTB patients.

Keywords: Extra-pulmonary tuberculosis (EPTB), Mycobacterial growth indicator tube (MGIT), Mycobacterium tuberculosis complex (MTBc), Non-tubercular mycobacterium (NTM) and multiple drug resistant (MDR).