Evaluation of the Abbott RealTime MTB and RealTime MTB INH/RIF Assays for Direct Detection of Mycobacterium tuberculosis Complex and Resistance Markers in Respiratory and Extrapulmonary Specimens

The Abbott RealTime MTB (RT MTB) assay is a new automated nucleic acid amplification test for the detection of Mycobacterium tuberculosis complex (MTBC) in clinical specimens. In combination with the RealTime MTB INH/RIF (RT MTB INH/RIF) resistance assay, which can be applied to RT MTB-positive spec...

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Bibliographic Details
Published in:Journal of clinical microbiology 2016-12, Vol.54 (12), p.3022-3027
Main Authors: Hofmann-Thiel, Sabine, Molodtsov, Nikolay, Antonenka, Uladzimir, Hoffmann, Harald
Format: Article
Language:English
Subjects:
Antitubercular Agents - therapeutic use
Drug Resistance, Multiple, Bacterial - genetics
Humans
Isoniazid - therapeutic use
Microbial Sensitivity Tests
Molecular Diagnostic Techniques - methods
Mycobacteriology and Aerobic Actinomycetes
Mycobacterium tuberculosis - drug effects
Mycobacterium tuberculosis - genetics
Mycobacterium tuberculosis - isolation & purification
Nontuberculous Mycobacteria - isolation & purification
Nucleic Acid Amplification Techniques - methods
Rifampin - therapeutic use
Sensitivity and Specificity
Tuberculosis, Pulmonary - diagnosis
Tuberculosis, Pulmonary - drug therapy
Tuberculosis, Pulmonary - microbiology
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Summary:The Abbott RealTime MTB (RT MTB) assay is a new automated nucleic acid amplification test for the detection of Mycobacterium tuberculosis complex (MTBC) in clinical specimens. In combination with the RealTime MTB INH/RIF (RT MTB INH/RIF) resistance assay, which can be applied to RT MTB-positive specimens as an add-on assay, the tests also indicate the genetic markers of resistance to isoniazid (INH) and rifampin (RIF). We aimed to evaluate the diagnostic sensitivity and specificity of RT MTB using different types of respiratory and extrapulmonary specimens and to compare performance characteristics directly with those of the FluoroType MTB assay. The resistance results obtained by RT MTB INH/RIF were compared to those from the GenoType MTBDRplus and from phenotypic drug susceptibility testing. A total of 715 clinical specimens were analyzed. Compared to culture, the overall sensitivity of RT MTB was 92.1%; the sensitivity rates for smear-positive and smear-negative samples were 100% and 76.2%, respectively. The sensitivities of smear-negative specimens were almost identical for respiratory (76.3%) and extrapulmonary (76%) specimens. Specificity rates were 100% and 95.8% for culture-negative specimens and those that grew nontuberculous mycobacteria, respectively. RT MTB INH/RIF was applied to 233 RT MTB-positive samples and identified resistance markers in 7.7% of samples. Agreement with phenotypic and genotypic drug susceptibility testing was 99.5%. In conclusion, RT MTB and RT MTB INH/RIF allow for the rapid and accurate diagnosis of tuberculosis (TB) in different types of specimens and reliably indicate resistance markers. The strengths of this system are the comparably high sensitivity with paucibacillary specimens, its ability to detect INH and RIF resistance, and its high-throughput capacities.
ISSN:0095-1137
1098-660X
DOI:10.1128/JCM.01144-16