TABLE 14

Summary of some molecular methods for M. tuberculosis complex AST

Molecular methodFormatDescription
Xpert MTB/RIF (Cepheid)Real-time PCR; detects mutations in the rpoB gene; turnaround time of 2 hFDA cleared; rifampin resistance only; ease of use
GenoType MTBDRplus and MTBDRsl (Hain Lifescience)Line probe assay; MTBDRplus detects mutations in the rpoB, inhA, and katG genes; MTBDRsl detects mutations in the gyrA, gyrB, rrs, and eis genes; turnaround time of 6 hResearch use only (U.S.); rifampin and isoniazid on the same line probe assay; additional assay for fluoroquinolones and aminoglycosides (amikacin or kanamycin)-cyclic peptides (capreomycin); interpretation of test results and result reporting require laboratory expertise; type of mutation is important and may direct additional testing necessary for patient treatment
Sequencing (Sanger sequencing and pyrosequencing)DNA sequencing; detects mutations in target genes; turnaround time of <24 hLaboratory-developed test; able to detect mutations in any targeted genes; pyrosequencing for shorter sequences only (e.g., not pncA); interpretation of test results and result reporting require laboratory expertise; type of mutation is important and may direct additional testing necessary for patient treatment