Tuberculosis remains a major public health issue globally, with an estimated 9.2 million new cases in 2006. A new threat to TB control is the emergence of drug resistant strains. These strains are harder to cure as standard anti-tuberculosis first line treatments are ineffective. Multi Drug Resistant Tuberculosis (MDR-TB) is defined as Mycobacterium tuberculosis that has developed resistance to at least rifampicin and isoniazid, and these strains now account for greater than 5% of worldwide cases. Mutations within the Rifampicin Resistance Determining Region (RRDR) of the rpoB gene are present in greater than 95% of strains that show rifampicin resistance by conventional drug susceptibility testing. As rifampicin mono resistance is extremely rare, and rifampicin resistance is usually associated with isoniaizd resistance, the RRDR region of the rpoB gene is a very useful surrogate marker for MDR-TB. Many molecular assays have been attempted based on this theory and have had varied levels of success. The three methods evaluated in this study are DNA sequencing of the rpoB, katG and inhA genes, the Genotype MTBDRplus line probe assay (Hain Lifesciences) and a novel method incorporating Real-Time PCR with High Resolution Melt analysis targeted at the RRDR using the Rotorgene 6000 (Corbett Lifesciences). The sensitivity for the detection of rifampicin resistance was far better using DNA sequencing or the commercially available line probe assay than detection by the Real-Time PCR method developed in this study.
| Identifer | oai:union.ndltd.org:ADTP/265837 |
| Date | January 2008 |
| Creators | Hansen, Tarrant William |
| Publisher | Queensland University of Technology |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
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