Hong Kong Med J 2015;21(Suppl 4):S4-7
Molecular tests for rapid detection of rifampicin and isoniazid resistance in Mycobacterium tuberculosis
PL Ho, WC Yam, CC Leung, WW Yew, TYW Mok, KS Chan, CM Tam
Department of Microbiology, University of Hong Kong
1. In patients suspected to have tuberculosis, a valid molecular test result was obtained in 94.3% and 88.3% of patients for the rpoB and katG loci, respectively, for prediction of drug susceptibility.
2. Molecular testing based on katG and rpoB enabled rapid detection of Mycobacterium tuberculosis resistance in 46.8% and 87.5% of patients infected with isoniazid- and rifampicin-resistant strains, respectively. The same number of patients infected with resistant strains with mutations in katG and rpoB were detected using the MTBDRplus line probe assay. The combined use of katG and inhA regulatory region in the MTBDRplus line probe assay increased the proportion of patients identified with INH-resistant MTB strains to 72.3%.
3. The rapid tests improved patient management by enabling earlier admission, more timely use of World Health Organization category IV anti-tuberculosis regimens and discontinuation of ineffective drugs.