TB FISH Assays for Diagnosis of Tuberculosis & MOTT

Diagnosis and treatment are the two most challenging aspects in TB and EPTB and are the topics of interest in the research field. Accurate diagnosis of Mycobacterial infection, appropriate treatment and implementation of control measures will help in reducing the TB burden.

A study was conducted by Department of Microbiology, Kasturba Medical College, Mangalore in collaboration with ID FISH Technologies, Palo Alto, California to evaluate a novel diagnostic technique for diagnosis of tuberculosis. The teams led by Dr Shrikala Baliga Professor KMC Mangalore and Dr Jyotsna Shah, Director, Product Development, ID FISH technologies evaluated Fluorescent In Situ Hybridization (FISH), a nucleic acid based test which detects the organism directly in the clinical specimen itself could be a cost effective test when compared to other nucleic acid based tests like PCR. The proposed study aimed at developing a FISH technique which is an easy, rapid and inexpensive method to detect Mycobacterium spp. in the pulmonary and extrapulmonary samples. The study proposed to standardize the detection and differentiation of M. tuberculosis from Non Tuberculous Mycobacteria.

The results of the study were promising. The sensitivity and specificity of FISH for Pulmonary samples was 95.8% and 83.5% and for EPTB was 57.6% and 99% respectively. The study also helped in differentiating infections caused by Mycobacterium tuberculosis and Atypical Mycobacteria. This was very helpful to clinicians as the line of treatment for both is very different. The experience for the same was also published in Journal of clinical tuberculosis and other Mycobacterial Diseases in 2020.

Dr Leesha Sharon worked on the evaluation and obtained her PHD in 2020 for Evaluation of Fluorescent In Situ Hybridization (FISH) as a Diagnostic Tool for Rapid Detection of Mycobacterium tuberculosis.

The study was also presented at International Congress of Infectious Diseases at Buenos Aries, Argentina on March 1st to March 4th 2018 as a poster Fluorescent In Situ Hybridization: A Rapid diagnostic test for the detection and speciation of Mycobacterial infection. The study was supported by Dr. Dhanashree B, Associate Professor, Suchitra Shenoy, HOD, and Ms Aishwarya Raj,  Research Assistant from Department of Microbiology.


1.       Role of fluorescence in situ hybridization in detecting mycobacterium avium complex presenting as fever in treatment failure HIV. Prabhu, V., Coelho, S., Achappa, B., Baliga, S., Sharon, L. & Shah, J., 12-2020, In: Journal of Clinical Tuberculosis and Other Mycobacterial Diseases. 21, 100188

2.       Rapid method for detecting and differentiating Mycobacterium tuberculosis complex and non-tuberculous mycobacteria in sputum by fluorescence in situ hybridization with DNA probes. Baliga, S., Murphy, C., Sharon, L., Shenoy, S., Biranthabail, D., Weltman, H., Miller, S., Ramasamy, R. & Shah, J., 01-10-2018, In: International Journal of Infectious Diseases. 75, p. 1-7 7 p

3.       3Dual color fluorescence in situ hybridization (FISH) assays for detecting Mycobacterium tuberculosis and Mycobacterium avium complexes and related pathogens in cultures. Shah, J., Weltman, H., Narciso, P., Murphy, C., Poruri, A., Baliga, S., Sharon, L., York, M., Cunningham, G., Miller, S., Caviedes, L., Gilman, R., Desmond, E. & Ramasamy, R., 2017, In: PLoS One. 12, 4, p. e0174989

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