Faculty Opinions recommendation of GenoType MTBDRplus assay for molecular detection of rifampin and isoniazid resistance in Mycobacterium tuberculosis strains and clinical samples.

ABSTRACT For Mycobacterium tuberculosis complex (MTBC), the rapid and accurate diagnosis of drug resistance is crucial to ensure early initiation of appropriate therapy. Recently, a new molecular diagnostic test, the FluoroType MTBDR, aimed at detecting rifampin and isoniazid resistance has become available. This study aimed to evaluate the FluoroType MTBDR in comparison to phenotypic drug susceptibility testing (DST) using M. tuberculosis complex isolates. MTBC isolates underwent phenotypic DST and were tested using the FluoroType MTBDR and Genotype MTBDRplus. Sanger sequencing of the key regions of rpoB, katG, inhA, and aphC was performed for isolates with discordant phenotypic and molecular results. Furthermore, isolates with specific wild-type bands missing in the Genotype MTBDRplus, indicating the presence of a mutation, were investigated by Sanger sequencing. Specificity and sensitivity, defined as the proportions of isolates correctly determined as susceptible and resistant by the FluoroType MTBDR compared to phenotypic DST, were calculated. A total of 180 culture isolates were included; phenotypic DST showed 85 isolates susceptible to isoniazid and rifampin, 7 with isoniazid monoresistance, 7 with rifampin monoresistance, and 81 with multidrug resistance. The specificity of the FluoroType MTBDR was 100% (95% confidence interval [CI], 96.0 to 100%) for both rifampin and isoniazid. The sensitivity was 91.7% (95% CI, 83.6 to 96.6%) for isoniazid and 98.9% (95% CI, 93.8 to 100.0%) for rifampin. The FluoroType MTBDR has a high sensitivity and specificity for the detection of rifampin and isoniazid resistance when using culture isolates.

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Pyrosequencing for Rapid Molecular Detection of Rifampin and Isoniazid Resistance in Mycobacterium tuberculosis Strains and Clinical Specimens

Journal of Clinical Microbiology ◽

10.1128/jcm.01239-11 ◽

2011 ◽

Vol 49 (10) ◽

pp. 3683-3686 ◽

Cited By ~ 27

Author(s):

N. Garcia-Sierra ◽

A. Lacoma ◽

C. Prat ◽

L. Haba ◽

J. Maldonado ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Molecular Detection ◽

Isoniazid Resistance ◽

Clinical Specimens

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Development of Au-Nanoprobes Combined with Loop-Mediated Isothermal Amplification for Detection of Isoniazid Resistance in Mycobacterium tuberculosis

Journal of Chemistry ◽

10.1155/2016/3474396 ◽

2016 ◽

Vol 2016 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Jutturong Ckumdee ◽

Thongchai Kaewphinit ◽

Kosum Chansiri ◽

Somchai Santiwatanakul

Keyword(s):

Mycobacterium Tuberculosis ◽

Multidrug Resistant ◽

Isothermal Amplification ◽

Clinical Samples ◽

Isoniazid Resistance ◽

Loop Mediated Isothermal Amplification ◽

Specificity And Sensitivity ◽

Mdr Tb ◽

Induced Aggregation ◽

Specific Sequences

Multidrug resistant tuberculosis (MDR-TB) is Mycobacterium tuberculosis that does not respond to isoniazid and rifampicin, so the condition worsens continuously and creates difficulties for treatment by public health control programmes, especially in developing countries. The real time polymerase chain reaction (PCR) combined with agarose gel electrophoresis or strip tests is useful molecular tools for diagnosis of MDR-TB. Novel loop-mediated isothermal amplification (LAMP) can also detect drug resistance, which is a one-point mutation, by designing inner primers of 5′ end specific with the mutant. Au-nanoprobes on hybridisation with LAMP products containing target-specific sequences remain red, whereas test samples without specific sequences in the probe turn purple due to salt-induced aggregation of the Au-nanoprobes. In this study, a strategy was designed based on the LAMP of a DNA sample coupled to specific Au-nanoprobes, which showed the potential to provide a rapid and sensitive method for detecting isoniazid resistance at katG gene position 315 (G→C). 46 clinical samples were tested and showed 100% specificity and sensitivity compared with Genotype® MDR-TB Plus. This method was advantageous because it is rapid, cheap, specific, and sensitive. Further, it does not require thermal cycles for MDR-TB detection.

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