ORIGINAL ARTICLE |
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Year : 2012 | Volume
: 30
| Issue : 1 | Page : 64-68 |
Evaluation of the microscopic observational drug susceptibility assay for rapid and efficient diagnosis of multi-drug resistant tuberculosis
RP Lazarus1, S Kalaiselvan1, KR John2, JS Michael1
1 Department of Microbiology, Christian Medical College, Vellore, 632004, Tamil Nadu, India 2 Department of Community Medicine, Christian Medical College, Vellore, 632004, Tamil Nadu, India
Correspondence Address:
J S Michael Department of Microbiology, Christian Medical College, Vellore, 632004, Tamil Nadu India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0255-0857.93039
Purpose: Tuberculosis (TB) is endemic in India and the burden of multi-drug-resistant tuberculosis (MDR-TB) is high. Early detection of MDR-TB is of primary importance in controlling the spread of TB. The microscopic observational drug susceptibility (MODS) assay has been described as a cost-effective and rapid method by which mycobacterial culture and the drug susceptibility test (DST) can be done at the same time. Materials and Methods: A total of 302 consecutive sputum samples that were received in an accredited mycobacteriology laboratory for conventional culture and DST were evaluated by the MODS assay. Results: In comparison with conventional culture on Lowenstein Jensen (LJ) media, the MODS assay showed a sensitivity of 94.12% and a specificity of 89.39% and its concordance with the DST by the proportion method on LJ media to isoniazid and rifampicin was 90.8% and 91.5%, respectively. The turnaround time for results by MODS was 9 days compared to 21 days by culture on LJ media and an additional 42 days for DST by the 1% proportion method. The cost of performing a single MODS assay was Rs. 250/-, compared to Rs. 950/- for culture and 1st line DST on LJ. Conclusion: MODS was found to be a sensitive and rapid alternative method for performing culture and DST to identify MDR-TB in resource poor settings.
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