Advances in Molecular Diagnosis of Tuberculosis.

Abstract

Acccurate and early diagnosis of tuberculosis is important for its effective management. Several methods for the diagnosis of tuberculosis are available which include tuberculin test, radiological examination and other imaging methods and sputum smear microscopy. Characteristic histopathology is a very important approach but there could be problems to get representative specimen and non specific features could be a problem. The immunology is often not conclusive as antibodies and delayed type hypersensitivity response persist long after the subsidence of sub-clinical or clinical disease. Sputum smear microscopy has both the problems of sensitivity and specificity. Culture is more sensitive and is presently the yardstick for diagnosis, but the time required and frequent negative results in paucibacillary specimens are important limitations. During the last decade, major advances in understanding the genetic structure of mycobacteria have been made. Based on this newer knowledge about the specific gene sequences, several gene probes/gene amplification systems for tuberculosis have been developed [1, 2]. These molecular tools and methods can be used for the confirmation of identity of isolates, direct detection of gene sequences from the clinical specimens and also molecular detection of drug resistance.