Performance of the Roche cobas MTB Assay for the Molecular Diagnosis of Pulmonary Tuberculosis in a High HIV Burden Setting

Scott, Lesley; David, Anura; Govender, Lyndel; Furrer, Jan; Rakgokong, Modiehi; Waja, Ziyaad; Martinson, Neil; Eisenberg, G. M.; Marlowe, Elizabeth M.; Stevens, Wendy

doi:10.1016/j.jmoldx.2020.06.018

Cited by 11 publications

(10 citation statements)

References 41 publications

(45 reference statements)

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“…Our study demonstrates that the cobas MTB assay meets the minimal performance characteristics stated in the WHO target product profile for a same-day diagnostic test detecting pulmonary TB as an alternative to smear microscopy, which is a sensitivity of >80% (smear-negative samples, >60%; smear-positive samples, 99%) and a specificity of >98% compared with culture ( 22 ). We observed that the overall sensitivity of cobas MTB (89.2%; 95% CI, 81.7 to 93.9%) was lower than in a study by Scott et al, who reported an overall sensitivity of 94.7% (95% CI, 88.1 to 98.3%) using decontaminated sputum sediments from individuals with presumptive or confirmed TB in South Africa ( 16 ). However, the proportion of smear-negative, culture-positive samples in our study was significantly larger (26.5% versus 7%) ( 16 ).…”

Section: Discussioncontrasting

confidence: 82%

“…MTBC DNA-positive samples are subsequently tested for resistance-associated mutations, which allows for diagnosis of RIF or INH monoresistance as well as MDR-TB. Limited data are available for the performance of the cobas MTB and MTB-RIF/INH assays compared to culture and other commercially available NAATs ( 16 , 17 ).…”

Section: Introductionmentioning

confidence: 99%

“…5% versus 7%)(16). In addition, Scott et al reported a sensitivity of 81.8% (95% CI 59.7-94.8%) for cobas MTB in smear-negative samples compared to 63.0% (95% CI 44.2-78.5%) in this study, which is likely a reflection of a lower bacterial burden even among smear-negative patients in Germany compared to smear-negative patients in South Africa(16).Both sensitivity and specificity of the cobas MTB assay for detection of MTBC DNA in clinical samples were comparable to or superior to that of five other platforms mentioned in the "WHO consolidated guidelines on tuberculosis (Module 3: Diagnosis)" (11). Therein, performance data were reported for Xpert MTB/RIF, Xpert MTB/RIF Ultra, Truenat TM MTB and Truenat TM MTB plus (Molbio Diagnostics India), and a loop-mediated isothermal amplification assay, with overall sensitivities and specificities ranging from 73-90% and 96-98%, respectively (11).…”

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confidence: 97%

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Evaluation of the Roche cobas MTB and MTB-RIF/INH Assays in Samples from Germany and Sierra Leone

et al. 2021

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Objective: The cobas® MTB and MTB-RIF/INH assays allow for detection of Mycobacterium tuberculosis complex (MTBC) nucleic acid, and rifampicin (RIF) and isoniazid (INH) resistance-associated mutations in an automated, high-throughput workflow. Here, we evaluated the performance of these assays, employing samples from low and high tuberculosis (TB) burden settings. Methods: 325 frozen, leftover respiratory samples collected from treatment-naïve patients with presumptive TB in Germany (n=280) and presumptive RIF resistant TB in Sierra Leone (n=45) were used in this study. Cobas MTB results for detection of MTBC DNA from N-acetyl-l-cysteine-sodium hydroxide (NALC-NaOH)-treated samples were compared to culture. Predictions of RIF and INH resistance by the cobas MTB-RIF/INH assay were compared to a composite reference standard (phenotypic drug susceptibility testing and line probe assay). Whole-genome sequencing was used to resolve discordances. Results: The overall sensitivity of cobas MTB for detection of MTBC DNA in culture-positive samples (n=102) was 89.2% (95% confidence interval [CI] 81.7–93.9%). The specificity of cobas MTB was 98.6% (95% CI 96.1–99.5%). Sensitivity and specificity for detection of RIF and INH resistance were 88.4% (95% CI 75.5–94.9%) and 97.6% (95% CI 87.4–99.6%), and 76.6% (95% CI 62.8–86.4%) and 100.0% (95% CI 90.8–100.0%), respectively. Discordant results for RIF and INH resistance were mainly due to uncommon mutations in samples from Sierra Leone that were not covered by the cobas MTB-RIF/INH assay. Conclusions: cobas MTB and MTB-RIF/INH provide accurate detection of MTBC DNA and resistance-associated mutations in respiratory samples. The influence of regional variations in the prevalence of resistance-conferring mutations requires further investigation.

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Section: Discussioncontrasting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

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confidence: 97%

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Evaluation of the Roche cobas MTB and MTB-RIF/INH Assays in Samples from Germany and Sierra Leone

et al. 2021

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“…A study in South Africa, in a high-HIV-burden setting, also reported that the Roche cobas MTB, Abbott RealTi m e MTB, and Xpert MTB/RIF assays ( n = 294) have similar performances of 94.7% (95% CI, 88% to 98%), 92.6% (95% CI, 85% to 97%), and 91.6% (95% CI, 84% to 96%), respectively. These assays also performed similarly among smear-negative, culture-positive individuals ( n = 221): 81.8% (95% CI, 60% to 95%), 72.7% (50% to 89%), and 72.7% (50% to 89%), respectively ( 11 ).…”

Section: Discussionmentioning

confidence: 87%

“…Published data from clinical studies to date demonstrate promising diagnostic performances of these assays when used in the appropriate scenarios ( 8 – 11 ). However, most of the available studies have important limitations.…”

Section: Introductionmentioning

confidence: 99%

Comparative Analytical Evaluation of Four Centralized Platforms for the Detection of Mycobacterium tuberculosis Complex and Resistance to Rifampicin and Isoniazid

et al. 2021

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Failure to rapidly identify drug-resistant tuberculosis (TB) increases the risk of patient mismanagement, the amplification of drug resistance and ongoing transmission. We generated comparative analytical data for four automated assays for detection of TB and multidrug-resistant (MDR) TB: Abbott RealTime MTB and MTB RIF/INH (Abbott), Hain Lifescience FluoroType® MTBDR (Hain), BD MAX™ MDR-TB (BD) and Roche cobas® MTB and MTB-RIF/INH (Roche). We included Xpert MTB/RIF (Xpert) and GenoType MTBDRplus as comparators for TB and drug resistance detection, respectively. We assessed analytical sensitivity for the detection of Mycobacterium tuberculosis complex using inactivated strains (M. tuberculosis H37Rv and M. bovis) spiked into TB-negative sputa and computed the 95% limit of detection (LOD95). We assessed the accuracy for rifampicin and isoniazid resistance detection using well characterized M. tuberculosis strains with high-confidence mutations accounting for >85% of first-line resistance mechanisms globally. For H37Rv and M. bovis, respectively, we measured LOD95 values of 3,781 and 2,926 (Xpert); 322 and 2,182 (Abbott); 826 and 4,301 (BD); 10,398 and 23,139 (Hain); 2,416 and 2,136 (Roche) genomes/mL. Assays targeting multi-copy genes or targets (Abbott, BD and Roche) showed increased analytical sensitivity compared to Xpert. Quantification of the panel by quantitative real-time PCR prevents the determination of absolute values and results reported here can only be interpreted for comparison purposes. All assays showed accuracy comparable to Genotype MTBDRplus for the detection of rifampicin and isoniazid resistance. The data from this analytical study suggest that the assays may have similar clinical performance to WHO-recommended molecular TB and MDR-TB assays.

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Mycobacterium tuberculosis Complex

Rowlinson,

Musser,

Khare

2023

ClinMicroNow

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Tuberculosis (TB) is caused by a group of closely related slowly growing mycobacteria, collectively named the Mycobacterium tuberculosis complex (MTBC). Members of the MTBC have undergone several taxonomic reclassifications, which has resulted in confusing nomenclature. Mycobacterial culture is currently considered the reference standard for MTBC detection. Until the early 1990s, typing of MTBC strains was limited to mycobacterial phage typing and drug resistance patterns, methods which have low discriminatory power that have been replaced by molecular genotypic methods. Antimicrobial susceptibility testing is a critical element of the MTBC laboratory workup. While cell‐based immunodiagnostics, such as tuberculin skin testing or interferon‐gamma release assays, can be used as part of establishing a diagnosis of active TB disease, they are mainly used as tests for latent TB infection and to determine exposure to TB.

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Performance of the Roche cobas MTB Assay for the Molecular Diagnosis of Pulmonary Tuberculosis in a High HIV Burden Setting

Cited by 11 publications

References 41 publications

Evaluation of the Roche cobas MTB and MTB-RIF/INH Assays in Samples from Germany and Sierra Leone

Evaluation of the Roche cobas MTB and MTB-RIF/INH Assays in Samples from Germany and Sierra Leone

Comparative Analytical Evaluation of Four Centralized Platforms for the Detection of Mycobacterium tuberculosis Complex and Resistance to Rifampicin and Isoniazid

Mycobacterium tuberculosis Complex

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