New Anyplex™ II MTB/MDR/XDR kit for detection of resistance mutations in M. tuberculosis cultures

Abstract

Settings: The new Anyplex™ II MTB/MDR/XDR PCR assay enables the joint analysis of mutations conferring resistance to first- and second-line anti-tuberculosis drugs and the detection of Mycobacterium tuberculosis.

Objectives: To evaluate the performance of the new Anyplex assay in detecting mutations that confer resistance to first- and second-line drugs in M. tuberculosis cultures.

Design: Results obtained using the new technique were compared with those obtained by phenotypic drug susceptibility testing (DST) and with two GenoType tests for the detection of mutations: GenoType(®) MTBDRplus and GenoType(®) MTBDRsl.

Results: For rifampicin resistance mutations, Anyplex displayed 97% sensitivity and 100% specificity compared with 100% and 100% for MTBDRplus. For isoniazid (INH) resistance, Anyplex displayed 61% sensitivity and 98% specificity compared with 62% and 98% for MTBDRplus. For second-line drugs, Anyplex recorded 95% sensitivity and 99% specificity in the detection of resistance to quinolones compared with 100% and 98% for the MTBDRsl. While both techniques displayed 100% specificity for aminoglycoside resistance mutations, sensitivity was 100% for Anyplex and 88% for MTBDRsl.

Conclusions: Results obtained using Anyplex agreed strongly with those obtained using the two GenoType molecular techniques and with phenotypic DST, except in the case of INH, due to the large number of genes involved in resistance to this drug.