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Title

Analysis of sequence diversity among IS6110 sequence of Mycobacterium tuberculosis: possible implications for PCR based detection

 

Authors

Sathish Sankar*, Suresh Kuppanan, Babu Balakrishnan, Balaji Nandagopal

 

Affiliation

Division of Biomedical Research, Sri Narayani Hospital and Research Centre, Thirumalaikodi, Sripuram, Vellore - 632 055, Tamil Nadu, India

 

Email

sathish3107@gmail.com; *Corresponding author

 

Phone

0416-2271202

 

Article Type

Current Trends

 

Date

Received June 01, 2011; Accepted June 06, 2011; Published June 23, 2011

 

Abstract

The IS6110 belongs to the family of insertion sequences (IS) of the IS3 category. This insertion sequence was reported to be specific for Mycobacterium tuberculosis complex and hence is extensively exploited for laboratory detection of the agent of tuberculosis and for epidemiological investigations based on polymerase chain reaction. IS6110 is 1361-bp long and within this sequence different regions have been utilized as targets in the identification of M. tuberculosis by PCR. However, the results are not always consistent, specific and sensitive. In recent years, a few clinical investigations raised concerns over IS6110 specificity and sensitivity in the diagnosis of tuberculosis due to false-positive (homology with other target DNA besides M. tuberculosis) or false negative (due to absence of copies of IS6110) results with IS6110 specific primers. To unravel the variations in IS6110 sequences, an insilico analysis of IS6110 sequence of different strains of M. tuberculosis was carried out. Our results of comparative analysis of IS6110 insertion sequences of M. tuberculosis complex suggests that, IS6110 insertion sequences harbored variations in its sequence, which is evident from the phylogenetic analysis. Importantly, IS6110 sequence has divergence within the copies of same strain and formed different clusters. A list of IS6110 specific primers used in various clinical investigation of tuberculosis was obtained from the literature and their performance scrutinized. Our study emphasizes the need to develop PCR assays (multiplex format) targeting more than one region of the genome of M. tuberculosis.

 

Keywords

IS6110, Mycobacterium tuberculosis, Phylogenetic analysis, Tuberculosis diagnosis
 

Citation

Sankar et al. Bioinformation 6(7): 283-285 (2011)
 

Edited by

P Kangueane

 

ISSN

0973-2063

 

Publisher

Biomedical Informatics

 

License

This is an Open Access article which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. This is distributed under the terms of the Creative Commons Attribution License.