Author(s)

Anto Jesuraj Uday Kumar^1,2*, Hiresave Srinivasa¹

¹Department of Microbiology, St. John’s Medical College, Bangalore, India.
²Infectious Disease Unit, St. John’s Research Institute, Bangalore, India.

Background: A new rapid Immunochromatographic test (ICT) kit (MPT64 TB Ag Kit) for detection of MPT64 Antigen in M. tuberculosis (MTB) isolates used for rapid identification of MTB isolates developed by SD (Standard Diagnostics) Bio line, South Korea was evaluated. The ICT is a rapid, reliable and cheaper method that can be used instead of conventional biochemical tests for confirming MTB in culture isolates in resource limited laboratories. The study also evaluated the ability of ICT to detect MPT64-Antigen before the micro MGIT could signal positive. Material/Methods: A total of 450 sputum samples of individual patients were used for the study. 152 isolates of Mycobacteria were recovered from solid and liquid media. These strains were tested for the detection of MPT64-antigen. H37Rv strain was served as the positive reference control and also used for early detection of Antigen experiment. Findings: The development of bands on both test and sample region when H37Rv strain was tested were seen (MPT64 antigen positive). When 138 MTB isolates were tested, it showed a similar banding pattern indicating 100% sensitivity. MPT64 band formation was not detected in any of the 14 isolates indicating 100% specificity. Both PPV & NPV were 100%. All the isolates negative for MPT64 Ag were confirmed as MOTT by conventional bio-chemical PNBA. The H37Rv strain showed a faint band from the 2nd day onwards from inoculation till 3rd day in the earlier Antigen detection experiment. Conclusion: Rapid identification of MTB culture isolate is a pressing need for diagnosis and proceeding to perform drug susceptibility testing. MPT64 TB Ag detection ICT kit is a rapid, reliable method, good substitute for molecular identification methods, and conventional biochemical test which is time-consuming and technically demanding. The early detection of Antigen can be used as an effective tool in diagnosis.

MTB (M. tuberculosis) MOTT (Mycobacteria Other than M. tuberculosis), PNBA (Para Nitro Benzoic Assay), MPT64 Antigen, ICT (Immunochromatography Test), MGIT (Mycobacterium Growth Indicator Tube), SD TB Ag MPT64 Rapid (Standard Diagnostics, Seoul, South Korea)

Uday Kumar, A. and Srinivasa, H. (2015) Fast and Accurate Identification of M. tuberculosis Complex Using an Immunochromatographic MPT64 Antigen Detection Test. Journal of Tuberculosis Research, 3, 149-156. doi: 10.4236/jtr.2015.34021.