Standardisation and evaluation of DNA-lanthanide fluorescence spectroscopy for determining rifampicin resistance in Mycobacterium tuberculosis clinical isolates.

Setting: Tuberculosis Research Centre, Chennai.

Objective: To rapidly identify multidrug-resistant Mycobacterium tuberculosis using a novel method.

Design: A new assay, based on DNA-lanthanide fluorescence, was standardised and evaluated using 93 each of coded rifampicin-resistant and rifampicin-sensitive M. tuberculosis clinical isolates for the correct identification of rifampicin resistance. The results obtained by the new assay were compared with the conventional results.

Results And Conclusion: The new assay gave a sensitivity and specificity of 88% and 85%, respectively. It is simple, easy to perform and requires 48 hours for the drug susceptibility results to be available after obtaining the primary culture.