Evaluation of a new automated Abbott RealTime MTB RIF/INH assay for qualitative detection of rifampicin/isoniazid resistance in pulmonary and extra-pulmonary clinical samples of Mycobacterium tuberculosis

Abstract

A new automated real-time PCR assay for the detection of rifampicin (RIF) and isoniazid (INH) resistance in Mycobacterium tuberculosis (MTB) was evaluated. A total of 163 clinical samples (128 pulmonary and 35 extra-pulmonary) were processed using four PCR assay kits: Abbott RealTime MTB RIF/INH, Genotype MTBDRplus, Xpert/MTB RIF, and Anyplex MTB/MDR. The results of phenotypic drug-susceptibility testing using BACTECMGIT 960 were used as reference. The sensitivity and specificity of the new Abbott RealTime MTB RIF/INH assay in comparison with phenotypic testing was 96.3% (95%CI 87.32%–100%) for RIF and 100% (95%CI 99.3%–100%) for INH; the sensitivity was 78.8% (95%CI 66.8%–90.9%) and the specificity was 100% (95%CI 98.9%–100%). The Abbott RealTime MTB RIF/INH test could be a valid method for detecting the most common mutations in strains resistant to RIF and INH.

Keywords:

• Abbott RealTime MTB RIF/INH Resistance assay
• M. tuberculosis
• mutations

Acknowledgments

This work was supported by the Spanish Ministry of Health and Consumer Affairs, Institute de Health Carlos III-ERDF, Spanish Network for Research into Infectious Diseases (REIPI RD06/0008).

Author contributions

All authors contributed toward data analysis, drafting and critically revising the paper and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.