Effectiveness of GenoType MTBDRsl in excluding TB drug resistance in a clinical trial

2021 ◽  
Vol 25 (10) ◽  
pp. 839-845
Author(s):  
M. Ejo ◽  
A. Van Deun ◽  
A. Nunn ◽  
S. Meredith ◽  
S. Ahmed ◽  
...  

OBJECTIVES: To assess the performance of the GenoType MTBDRsl v1, a line-probe assay (LPA), to exclude baseline resistance to fluoroquinolones (FQs) and second-line injectables (SLIs) in the Standard Treatment Regimen of Anti-tuberculosis Drugs for Patients With MDR-TB 1 (STREAM 1) trial.METHODS: Direct sputum MTBDRsl results in the site laboratories were compared to indirect phenotypic drug susceptibility testing (pDST) results in the central laboratory, with DNA sequencing as a reference standard.RESULTS: Of 413 multidrug-resistant TB (MDR-TB) patients tested using MTBDRsl and pDST, 389 (94.2%) were FQ-susceptible and 7 (1.7%) FQ-resistant, while 17 (4.1%) had an inconclusive MTBDRsl result. For SLI, 372 (90.1%) were susceptible, 5 (1.2%) resistant and 36 (8.7%) inconclusive. There were 9 (2.3%) FQ discordant pDST/MTBDRsl results, of which 3 revealed a mutation and 5 (1.3%) SLI discordant pDST/MTBDRsl results, none of which were mutants on sequencing. Among the 17 FQ- and SLI MTBDRsl-inconclusive samples, sequencing showed 1 FQ- and zero SLI-resistant results, similar to frequencies among the conclusive MTBDRsl. The majority of inconclusive MTBDRsl results were associated with low bacillary load samples (acid-fast bacilli smear-negative or scantily positive) compared to conclusive results (P < 0.001).CONCLUSION: MTBDRsl can facilitate the rapid exclusion of FQ and SLI resistances for enrolment in clinical trials.

2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Margaretha de Vos ◽  
Brigitta Derendinger ◽  
Tania Dolby ◽  
John Simpson ◽  
Paul D. van Helden ◽  
...  

ABSTRACT Most cases of multidrug-resistant (MDR) tuberculosis (TB) are never diagnosed (328,300 of the ∼490,000 cases in 2016 were missed). The Xpert MTB/RIF assay detects resistance only to rifampin, despite ∼20% of rifampin-resistant cases being susceptible to isoniazid (a critical first-line drug). Consequently, many countries require further testing with the GenoType MTBDRplus assay. However, MTBDRplus is not recommended for use on smear-negative specimens, and thus, many specimens require culture-based drug susceptibility testing. Furthermore, MTBDRplus requires specialized expertise, lengthy hands-on time, and significant laboratory infrastructure and interpretation is not automated. To address these gaps, we evaluated the accuracy of the FluoroType MTBDR (FluoroType) assay. Sputa from 244 smear-positive and 204 smear-negative patients with presumptive TB (Xpert MTB positive, n = 343) were tested. Culture and MTBDRplus on isolates served as reference standards (for active TB and MDR-TB, respectively). Sanger sequencing and MTBDRplus, both of which were performed on sputa, were used to resolve discrepancies. The sensitivity of FluoroType for the detection of M. tuberculosis complex was 98% (95% confidence interval [CI], 95 to 99%) and 92% (95% CI, 84 to 96%) for smear-positive and smear-negative specimens, respectively (232/237 versus 90/98 specimens; P < 0.009). The sensitivity and specificity for smear-negative specimens were 100% and 97%, respectively, for rifampin resistance; 100% and 98%, respectively, for isoniazid resistance; and 100% and 100%, respectively, for MDR-TB. FluoroType identified 98%, 97%, and 97% of the rpoB, katG, and inhA promoter mutations, respectively. FluoroType has excellent sensitivity with sputa equivalent to that of MTBDRplus with the isolates and can provide rapid drug susceptibility testing for rifampin and isoniazid. In addition, the capacity of FluoroType to simultaneously identify virtually all mutations in the rpoB, katG, and inhA promoter may be useful for individualized treatment regimens.


2019 ◽  
Vol 147 ◽  
Author(s):  
R. S. Salvato ◽  
S. Schiefelbein ◽  
R. B. Barcellos ◽  
B. M. Praetzel ◽  
I. S. Anusca ◽  
...  

AbstractTuberculosis (TB) is the leading cause of death among infectious diseases worldwide. Among the estimated cases of drug-resistant TB, approximately 60% occur in the BRICS countries (Brazil, Russia, India, China and South Africa). Among Brazilian states, primary and acquired multidrug-resistant TB (MDR-TB) rates were the highest in Rio Grande do Sul (RS). This study aimed to perform molecular characterisation of MDR-TB in the State of RS, a high-burden Brazilian state. We performed molecular characterisation of MDR-TB cases in RS, defined by drug susceptibility testing, using 131Mycobacterium tuberculosis (M.tb)DNA samples from the Central Laboratory. We carried out MIRU-VNTR 24loci, spoligotyping, sequencing of thekatG,inhA andrpoB genes and RDRiosublineage identification. The most frequent families found were LAM (65.6%) and Haarlem (22.1%). RDRiodeletion was observed in 42 (32%) of theM.tbisolates. Among MDR-TB cases, eight (6.1%) did not present mutations in the studied genes. In 116 (88.5%)M.tbisolates, we found mutations associated with rifampicin (RIF) resistance inrpoB gene, and in 112 isolates (85.5%), we observed mutations related to isoniazid resistance inkatG andinhA genes. An insertion of 12 nucleotides (CCAGAACAACCC) at the 516 codon in therpoB gene, possibly responsible for a decreased interaction of RIF and RNA polymerase, was found in 19/131 of the isolates, belonging mostly to LAM and Haarlem families. These results enable a better understanding of the dynamics of transmission and evolution of MDR-TB in the region.


2019 ◽  
Vol 45 (2) ◽  
Author(s):  
Angela Pires Brandao ◽  
Juliana Maira Watanabe Pinhata ◽  
Rosangela Siqueira Oliveira ◽  
Vera Maria Neder Galesi ◽  
Helio Hehl Caiaffa-Filho ◽  
...  

ABSTRACT Objective: To evaluate the rapid diagnosis of multidrug-resistant tuberculosis, by using a commercial line probe assay for rifampicin and isoniazid detection (LPA-plus), in the routine workflow of a tuberculosis reference laboratory. Methods: The LPA-plus was prospectively evaluated on 341 isolates concurrently submitted to the automated liquid drug susceptibility testing system. Results: Among 303 phenotypically valid results, none was genotypically rifampicin false-susceptible (13/13; 100% sensitivity). Two rifampicin-susceptible isolates harboured rpoB mutations (288/290; 99.3% specificity) which, however, were non-resistance-conferring mutations. LPA-plus missed three isoniazid-resistant isolates (23/26; 88.5% sensitivity) and detected all isoniazid-susceptible isolates (277/277; 100% specificity). Among the 38 (11%) invalid phenotypic results, LPA-plus identified 31 rifampicin- and isoniazid-susceptible isolates, one isoniazid-resistant and six as non-Mycobacterium tuberculosis complex. Conclusions: LPA-plus showed excellent agreement (≥91%) and accuracy (≥99%). Implementing LPA-plus in our setting can speed up the diagnosis of multidrug-resistant tuberculosis, yield a significantly higher number of valid results than phenotypic drug susceptibility testing and provide further information on the drug-resistance level.


2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Elina Maharjan ◽  
Narayan Dutt Pant ◽  
Sanjeev Neupane ◽  
Jyoti Amatya ◽  
Bhawana Shrestha

The main aims of this study were to study the patterns of mutations in rpoB, katG, and inhA genes in Mycobacterium tuberculosis strains isolated from patients from Nepal and to evaluate the performance of genotype MTBDRplus assay, taking conventional drug susceptibility testing as gold standard for diagnosis of MDR-TB. A total of 69 Mycobacterium tuberculosis strains isolated from 73 smear positive sputum samples from patients suspected of suffering from multidrug-resistant tuberculosis were used in our study. The drug susceptibility pattern of Mycobacterium tuberculosis isolated from these sputum specimens was determined by using genotype MTBDRplus assay taking conventional drug susceptibility testing as reference. The sensitivity and specificity of the genotype MTBDRplus assay for the detection of MDR-TB were found to be 88.7% and 100%, respectively. 88.7% of the rifampicin resistant isolates had mutations in rpoB gene. Similarly, 79.7% and 9.4% of isoniazid resistant isolates had mutations in katG and inhA genes, respectively. Genotype MTBDRplus assay was found to be very rapid and highly sensitive and specific method for diagnosis of MDR-TB and will be very helpful for early diagnosis of MDR-TB in high tuberculosis burden countries.


Biomedicine ◽  
2021 ◽  
Vol 41 (2) ◽  
pp. 472-476
Author(s):  
Chandan Kumar Poddar ◽  
Narmata Kumari ◽  
Rakesh Kumar ◽  
Shivendra Kumar Shahi ◽  
Naresh Kumar ◽  
...  

Introduction and Aim: India has the uppermost trouble of Multidrug resistant tuberculosis (MDR-TB) is a major challenge controlling resistance, reducing transmission and improving handling outcomes in MDR-TB patients is dependent on susceptibility testing. Isoniazid (INH) and rifampicin (Rif) are the key first-line antituberculosis drugs, and resistance to these drugs i.e., MDR-TB, is likely to result in treatment failure and poor clinical outcomes. The present study was done to compare the performance of line probe assay test (GenoType® MTBDRplus) with liquid culture (MGIT 960) system for the detection of resistance to first-line drugs.   Materials and Methods: We estimate the performance of LPAs to BACTEC MGIT 960 system for susceptibility testing of bacterial resistance to first-line drugs: rifampicin (RIF), isoniazid (INH).   Results: We performing Drug susceptibility testing (DST), 219/258 MTB cultures were viable after subculture the results of DST using the MGIT 960 system were compared to those obtained by line probe assay. LPA detected a total 46/258 (17.81%) samples as drug resistant, of which 35/258 (13.70%) were resistant to both rifampicin and isoniazid (MDR), 6/258 (2.28%) were rifampicin mono?resistant samples and 11/258 (4.11%) were isoniazid mono?resistant. Out of the culture?positive samples (219), LPA detected 39/219 (17.83%) as drug?resistant, of which 31/219 (14.2%) were resistant to both rifampicin and isoniazid, 5/193 (2.08%) were rifampicin mono?resistant and 8/219 (3.7%) were isoniazid mono?resistant. Conclusion: Drug resistant TB poses an enormous threat to TB control programs worldwide. Effective treatment of MDR-TB is very expensive, particularly in middle income countries such as India.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yong Chen ◽  
Zhengan Yuan ◽  
Xin Shen ◽  
Jie Wu ◽  
Zheyuan Wu ◽  
...  

Introduction. Second-line antituberculosis drugs (SLDs) are used for treating multidrug-resistant tuberculosis (MDR-TB). Prolonged delays before confirming MDR-TB with drug susceptibility testing (DST) could result in transmission of drug-resistant strains and inappropriate use of SLDs, thereby increasing the risk of resistance to SLDs. This study investigated the diagnostic delay in DST and prevalence of baseline SLD resistance in Shanghai and described the distribution of SLD resistance with varied delays to DST.Methods. All registered patients from 2011 to 2013 in Shanghai were enrolled. Susceptibility to ofloxacin, amikacin, kanamycin, and capreomycin was tested. Total delay in DST completion was measured from the onset of symptoms to reporting DST results.Results. Resistance to SLDs was tested in 217 of the 276 MDR-TB strains, with 118 (54.4%) being resistant to at least one of the four SLDs. The median total delay in DST was 136 days. Patients with delay longer than median days were roughly twice more likely to have resistance to at least one SLD (OR 2.22, 95% CI 1.19–4.11).Conclusions. During prolonged delay in DST, primary and acquired resistance to SLDs might occur more frequently. Rapid diagnosis of MDR-TB, improved nosocomial infection controls, and regulated treatment are imperative to prevent SLD resistance.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yang Che ◽  
Dingyi Bo ◽  
Xiang Lin ◽  
Tong Chen ◽  
Tianfeng He ◽  
...  

Abstract Background Detection of pyrazinamide (PZA) resistance in Mycobacterium tuberculosis (TB) patients is critical, especially in dealing with multidrug-resistant Mycobacterium tuberculosis (MDR-TB) case. Up to date, PZA drug susceptibility testing (DST) has not been regularly performed in China. The prevalence and molecular characteristics of PZA resistance in M.tuberculosis isolates, especially MDR-TB have not been studied in Ningbo, China. This study aimed to analyze the phenotypic and molecular characterization of PZA resistance among MDR-TB isolates in Ningbo. Methods A total of 110 MDR-TB isolates were collected from the TB patients who were recorded at local TB dispensaries in Ningbo. All clinical isolates were examined by drug susceptibility testing and genotyping. DNA sequencing was used to detect mutations in the pncA gene associated with PZA resistance. Results The prevalence of PZA resistance among MDR-TB strains in Ningbo was 59.1%. With regard to the history and the outcome of treatments among MDR-TB cases, the percentages of re-treated MDR-TB patients in the PZA-resistant group and of successful patients in PZA-susceptible group were significantly higher than the ones in the PZA-susceptible group and in the PZA-resistant group, respectively (P = 0.027, P = 0.020). The results showed that the resistance of streptomycin (67.7% vs 46.7%, P = 0.027), ethambutol (56.9% vs 33.3%, P = 0.015), ofloxacin (43.1% vs 11.1%, P = 0.000), levofloxacin (43.1% vs 11.1%, P = 0.000), pre-XDR (pre-Xtensively Drug Resistance) (38.5% vs 15.6%, P = 0.009), were more frequently adverted among PZA-resistant isolates compared with PZA-susceptible isolates. In addition, 110 MDR-TB was composed of 87 (PZA resistant, 78.5%) Beijing strains and 23 (PZA resistant, 21.5%) non-Beijing strains. Fifty-four out of 65 (83.1%) PZA-resistant MDR strains harbored a mutation located in the pncA gene and the majority (90.7%) were point mutations. Compared with the phenotypic characterization, DNA sequencing of pncA has sensitivity and specificity of 83.1 and 95.6%. Conclusion The mutations within pncA gene was the primary mechanism of PZA resistance among MDR-TB and DNA sequencing of pncA gene could provide a rapid detection evidence in PZA drug resistance of MDR-TB in Ningbo.


2021 ◽  
Vol 30 (3) ◽  
pp. 143-151
Author(s):  
Noha S. Soliman ◽  
Sahar M. Khairat ◽  
Mohamed Abdullah ◽  
Yasmin Adel El-Mahdy

Background: Multidrug-resistant tuberculosis (MDR-TB) and infections by nontuberculous mycobacteria (NTM) are diseases of major public health concern. Objective: The aim of the present work is to study the prevalence and patterns of MDRTB as well as the characterization of isolated NTM species. Methodology: All samples (1069) were subjected to smear microscopy, culture on Lowenstein-Jensen (LJ) media, and phenotypic drug susceptibility testing (DST) of MTB to isoniazid (INH), rifampin (RF), streptomycin (S), and ethambutol (E). GeneXpert was used for direct detection of MTB and RF resistance. Matrix-assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry (MS) was utilized for characterizing isolated NTM species. Results: M.tuberculosis (MTB) was isolated at a rate of 95.3% (1019/1069). MDR-TB was detected at rate of 7.16% with significant patterns for INH + RF + S + E (46.5%) and INR + RF (24.6%) (P-value <0.001). RF resistance was detected at a rate of 27.2% by GeneXpert. Seven NTM species (0.6%) were isolated in culture of which M.porcinum and M.fortuitum had confident identification by MALDI-TOF (score ≥1.8). Conclusion: MDR-TB rate was found to be 7.16% with significant dominance for INH + RF + S + E and INR + RF resistance patterns, while NTM rate was 0.6%.


2020 ◽  
Vol 14 (03) ◽  
pp. 268-276
Author(s):  
Krairerk Suthum ◽  
Worada Samosornsuk ◽  
Seksun Samosornsuk

Introduction: Multidrug-resistant tuberculosis (MDR-TB) is commonly found in Thailand especially in the public health region 5, the Western region of Thailand. This study’s aim was to characterize katG, inhA, rpoB and pncA genes in Mycobacterium tuberculosis. Methodology: One hundred strains of Mycobacterium tuberculosis (MTB) were isolated from sputum samples of MDR-TB risk patients in the laboratory of the Office of Disease Prevention and Control 5th Ratchaburi province, Thailand from January to December 2015. Drug susceptibility testing (DST) was performed using a BACTEC MGIT 960 system. Furthermore, the genes katG, inhA, rpoB and pncA were characterized by DNA sequencing. Results: Of a total of 100 MTB samples which underwent drug susceptibility testing, 42% showed isoniazid (INH) and rifampicin (RIF) resistance, and a further 25% showed INH mono-resistance (25%). The most common gene mutations found using DNA sequencing were katG_Ser315Thr (70%), rpoB_Ser531leu (81%) and pncA_Ile31Thr (84%). The common mutation of pncA_Ile31Thr substitution was detected in 26 of 91 (29%) pyrazinamide (PZA) susceptible isolates. Conclusion: Using DNA sequencing to screen for gene mutations conferring drug resistance may be feasible and use less time than using DST to detect resistance patterns.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Bijay Kumar Sharma ◽  
Shiva Bhandari ◽  
Bhagwan Maharjan ◽  
Bhawana Shrestha ◽  
Megha Raj Banjara

Rapid line probe assay (LPA) can be a practical and rapid alternative to the slow conventional phenotypic drug susceptibility testing (DST) for detection of drug resistant tuberculosis (TB). The purpose of this study is to determine the diagnostic accuracy of Genotype MTBDRplus, LPA for TB, and compare its performance with conventional DST. A total of 54 culture samples were analyzed for DST using both conventional proportion method and MTBDRplus, where conventional DST identified 43 isolates (79.6%) as drug resistant. Among these 43 drug resistant isolates, 30 isolates (69.7%) were found to be multidrug resistant (MDR). Of all observed mutations using MTBDRplus, codon 531 of rpoB gene and codon 315 of katG gene were found to have highest mutational frequency for RIF resistance (64.7%) and INH resistance (96.8%), respectively. In the present study, MTBDRplus assay was shown to have excellent specificity (100%) for both RIF and INH resistance while sensitivity of the assay was little lower with value of 89.4% for RIF resistance and 91.4% for INH resistance. Therefore, the assay can be a rapid, reliable, and promising molecular test for early detection of MDR-TB in Nepal.


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