Use of Cost Effective Semi-Automated (Mannual/Micro) MGIT System over BACTEC 960 to Perform First Line Anti-Tuberculosis Drugs Sensitivity Testing

Abstract

Introduction: Multi-drug resistant tuberculosis (MDR-TB) that is the tuberculosis that is resistant to at least 2 of the first line anti-tuberculosis drugs is fatal infectious disease. Cases of MDR-TB are now increasing with 30,000 cases of MDR-TB reported in 2013 by national TB programme. Rapid diagnosis of MDR-TB is extremely important for rapid treatment of patient and to prevent spread of MDR-TB to other. BACTEC 960 system helps in rapid diagnosis but purchase of expensive instrument for the same is the limitation. However, the same purpose can be solved by use of semi-automated MGIT system. Aims and Objectives: Aim of this study is to do drug sensitivity testing of the first line anti-tuberculosis drugs with the use of semi-automated MGIT systems. 350 newly registered and suspected cases of tuberculosis in tertiary care hospital were included. Samples were processed for digestion and decontamination and inoculated in MGIT tubes and also on LJ medium. Reading was taken using semi-automated MGIT system. Positive tubes were confirmed by rapid test for M. tuberculosis and then drug sensitivity was performed. Result: Out of 350 samples, 62% were sputum; 33% were pleural fluid and rest 5% were lymph node, Ascetic fluid, CSF, pus. Average day of positivity by MGIT was 13 - 20 days as compared to 25 - 37 days by solid medium, which was statistically significant with p value < 0.01. MDR cases were 2% out of 350 samples. Conclusion: Manual MGIT System is a simple, efficient, safe to use diagnostic system. It does not require any expensive/special instrumentation other than the UV lamp for detection of fluorescence. The rapidity by which mycobacteria are detected is the most important advantage of the Manual MGIT. In areas with limited resources where purchase of expensive instruments such as the MGIT960 is out of scope, the use of manual MGIT for rapid susceptibility testing for MDR-TB could be a possibility.