Assessing the utility of three TaqMan probes for the diagnosis of tuberculosis and resistance to rifampin and isoniazid in Veracruz, México

2012 ◽  
Vol 58 (3) ◽  
pp. 318-325 ◽  
Author(s):  
Roberto Zenteno-Cuevas ◽  
Betzaida Cuevas-Cordoba ◽  
Antonio Enciso ◽  
Leonor Enciso ◽  
Aremy Cuellar
Keyword(s):  
Drug Resistance ◽  
Molecular Mechanisms ◽  
Rpob Gene ◽  
Diagnostic Value ◽  
Multidrug Resistant ◽  
Molecular Probes ◽  
Clinical Isolates ◽  
Drug Resistant ◽  
Taqman Probes ◽  
Resistant Tuberculosis

Mutations at codons 526 and 531 in the rpoB gene and at 315 in the katG gene are considered diagnostic markers for resistance to rifampin and isoniazid in tuberculosis. The aim of this study was to design and evaluate three TaqMan probes for the identification of these mutations in 138 respiratory samples positive for acid-fast bacilli, and 32 clinical isolates from a region with considerable levels of drug resistance. The specificities of the probes for the diagnosis of resistance to both drugs were 100%; however, the sensitivities were calculated to be 50% for isoniazid and 56% for rifampin. DNA sequencing of rpoB and katG; and the spoligotyping assay of the clinical isolates, confirmed the diversity of the mutations and the presence of 11 spoligotypes with a shared international type and eight unique spoligotypes. Analysis of the respiratory samples identified 22 (16%) as drug-resistant and 4 (3%) as multidrug-resistant tuberculosis. The diagnostic value of the TaqMan probes was compromised by the diversity of mutations found in the clinical isolates. This highlights the need for better understanding of the molecular mechanisms responsible for drug resistance prior to the use of molecular probes, especially in regions with significant levels of drug-resistant tuberculosis.

scholarly journals Association between embB Codon 306 Mutations and Drug Resistance in Mycobacterium tuberculosis

2007 ◽  
Vol 51 (7) ◽  
pp. 2618-2620 ◽  
Author(s):  
Xin Shen ◽  
Guo-miao Shen ◽  
Jie Wu ◽  
Xiao-hong Gui ◽  
Xia Li ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Odds Ratio ◽  
Rapid Detection ◽  
Multidrug Resistant ◽  
Drug Resistant ◽  
Drug Resistant Tuberculosis ◽  
Candidate Marker ◽  
Resistant Tuberculosis

ABSTRACT embB306 mutants were detected in both ethambutol (EMB)-resistant and EMB-susceptible strains of Mycobacterium tuberculosis. Multidrug-resistant (MDR) strains had a higher proportion of embB306 mutants than non-MDR strains (odds ratio, 6.78; P < 0.001). The embB306 locus is a candidate marker for rapid detection of MDR and extremely drug resistant tuberculosis.

scholarly journals Drug-Resistant Tuberculosis 2020: Where We Stand

2020 ◽  
Vol 10 (6) ◽  
pp. 2153 ◽  
Author(s):  
Angelo Iacobino ◽  
Lanfranco Fattorini ◽  
Federico Giannoni
Keyword(s):  
Molecular Mechanisms ◽  
Drug Distribution ◽  
Multidrug Resistant ◽  
Diagnostic Methods ◽  
World Health ◽  
Drug Resistant ◽  
Comprehensive Overview ◽  
Resistant Tuberculosis ◽  
Health Organization ◽  
Incident Cases

The control of tuberculosis (TB) is hampered by the emergence of multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb) strains, defined as resistant to at least isoniazid and rifampin, the two bactericidal drugs essential for the treatment of the disease. Due to the worldwide estimate of almost half a million incident cases of MDR/rifampin-resistant TB, it is important to continuously update the knowledge on the mechanisms involved in the development of this phenomenon. Clinical, biological and microbiological reasons account for the generation of resistance, including: (i) nonadherence of patients to their therapy, and/or errors of physicians in therapy management, (ii) complexity and poor vascularization of granulomatous lesions, which obstruct drug distribution to some sites, resulting in resistance development, (iii) intrinsic drug resistance of tubercle bacilli, (iv) formation of non-replicating, drug-tolerant bacilli inside the granulomas, (v) development of mutations in Mtb genes, which are the most important molecular mechanisms of resistance. This review provides a comprehensive overview of these issues, and releases up-dated information on the therapeutic strategies recently endorsed and recommended by the World Health Organization to facilitate the clinical and microbiological management of drug-resistant TB at the global level, with attention also to the most recent diagnostic methods.

scholarly journals Diagnostic Value of GeneChip for Detection of Resistant Mycobacterium tuberculosis in Patients with Differing Treatment Histories

2014 ◽  
Vol 53 (1) ◽  
pp. 131-135 ◽  
Author(s):  
Limei Zhu ◽  
Qiao Liu ◽  
Leonardo Martinez ◽  
Jinyan Shi ◽  
Cheng Chen ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Diagnostic Value ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Standard Drug ◽  
Related Data ◽  
Resistant Tuberculosis ◽  
Mdr Tb ◽  
Previously Treated

The increasing burden of drug-resistant tuberculosis (TB) poses an escalating threat to national TB control programs. To assist appropriate treatment for TB patients, accurate and rapid detection of drug resistance is critical. The GeneChip test is a novel molecular tool for the diagnosis of TB drug resistance. Performance-related data on GeneChip are limited, and evaluation in new and previously treated TB cases has never been performed. We evaluated the diagnostic performance of GeneChip in detecting resistance to rifampin (RMP) and isoniazid (INH) and in detecting multidrug-resistant tuberculosis (MDR-TB) in comparison with standard drug susceptibility testing (DST) and compared the results in a group of previously treated and newly detected TB patients in an urban area in southeastern China. One thousand one hundred seventy-three (83.8%) new cases and 227 (16.2%) previously treated cases were collected between January 2011 and September 2013. The GeneChip showed a specificity of 97.8% and a sensitivity of 94.8% for detection of RMP resistance and 97.3% and 70.9%, respectively, for INH resistance in new cases. For previously treated cases, the overall sensitivity, specificity, and agreement rate are 94.6%, 91.3%, and 92.1%, respectively, for detection of RMP resistance and 69.7%, 95.4%, and 86.8%, respectively, for INH resistance. The sensitivity and specificity of MDR-TB were 81.8% and 99.0% in new cases and 77.8% and 93.4% in previously treated cases, respectively. The GeneChip system provides a simple, rapid, reliable, and accurate clinical assay for the detection of TB drug resistance, and it is a potentially important diagnostic tool in a high-prevalence area.

scholarly journals Diagnosis of Multidrug-Resistant Tuberculosis and Extensively Drug-Resistant Tuberculosis: Current Standards and Challenges

2008 ◽  
Vol 19 (2) ◽  
pp. 169-172 ◽  
Author(s):  
Giovanni Battista Migliori ◽  
Alberto Matteelli ◽  
Daniela Cirillo ◽  
Madhukar Pai
Keyword(s):  
Drug Resistance ◽  
Rapid Determination ◽  
Scale Up ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Resistant ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Extensively Drug Resistant ◽  
Mdr Tb

INTRODUCTION: The emergence of multidrug-resistant tuberculosis (MDR-TB) and, more recently, extensively drug-resistant TB (XDR-TB) is widely considered a serious threat to global TB control. Over 400,000 new cases of MDR-TB occur each year and, although their rates are currently unknown, XDR-TB cases have been detected in every country where there is capacity to detect them (including Canada).METHODS: The present article provides a narrative overview of the various diagnostic options available for XDR-TB, including conventional tools and newer rapid tests for drug resistance. Available data suggest that automated liquid cultures are highly accurate and their use is rapidly expanding. Newly developed phenotypic tests include TK Medium (Salubris Inc, USA), microscopic-observation drug-susceptibility assay, FASTPlaque-Response bacteriophage assay (Biotec Laboratories Ltd, UK), colorimetric redox indicator methods and the microcolony method. These tests are usually cheaper but not always simple to perform, with some requiring high standards of biosafety and quality control. Among the newly developed phenotypic methods, reverse hybridization-based assays, referred to as line probe assays, represent a useful tool because of their superior accuracy and cost-effectiveness.CONCLUSIONS: To effectively address the threats of MDR-TB and XDR-TB, global initiatives are required to scale-up culture and drug susceptibility testing capacities, especially in high-burden countries where such capacity is scarce. In parallel, efforts are needed to expand the use of novel and emerging technologies (ie, molecular diagnostics) for the rapid determination of drug resistance.

Drug Resistance in Newly Presenting and Previously Treated Tuberculosis Patients in Guangxi Province, People’s Republic of China

2017 ◽  
Vol 29 (4) ◽  
pp. 296-303 ◽  
Author(s):  
Dan Luo ◽  
Jinming Zhao ◽  
Mei Lin ◽  
Feiying Liu ◽  
Shuhai Huang ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Multidrug Resistant ◽  
Beijing Strain ◽  
Drug Resistant ◽  
Republic Of China ◽  
Randomized Sampling ◽  
Multiple Treatment ◽  
Resistant Tuberculosis ◽  
Treatment Interruptions ◽  
Cluster Randomized

Drug-resistant Mycobacterium tuberculosis strains are a major threat to the control of tuberculosis (TB), but the prevalence of drug-resistant TB is still unknown in the southern ethnic region of China. A cluster-randomized sampling method was used to include the study population. Isolates were tested for resistance to 6 antituberculosis drugs, and genotyped to identify Beijing strains. Overall, 11.3% (139/1229) of new cases and 33.0% (126/382) of retreated cases had drug-resistant tuberculosis. Multiple previous TB treatment episodes and multiple treatment interruptions were risk factors for both drug-resistant and multidrug-resistant TB among retreated cases. A total of 53.2% of the patients were infected with a Beijing strain of M tuberculosis. Infection with a Beijing strain was significantly associated with drug resistance among new cases (odds ratio, 1.44; 95% CI, 1.01-2.07). Novel strategies to rapid diagnosis and effective treatment are urgently needed to prevent the development of drug resistance.

scholarly journals The Structural Modeling of the Interaction between Levofloxacin and theMycobacterium tuberculosisGyrase Catalytic Site Sheds Light on the Mechanisms of Fluoroquinolones Resistant Tuberculosis in Colombian Clinical Isolates

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
N. Alvarez ◽  
E. Zapata ◽  
G. I. Mejía ◽  
T. Realpe ◽  
P. Araque ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Multidrug Resistant ◽  
Catalytic Site ◽  
Clinical Isolates ◽  
Isopropyl Group ◽  
Acid Base ◽  
Base Interaction ◽  
Resistant Tuberculosis ◽  
Acetyl Group ◽  
Acid Base Interaction

We compared the prevalence of levofloxacin (LVX) resistance with that of ofloxacin (OFX) and moxifloxacin (MFX) among multidrug resistant (MDR)MTBclinical isolates collected in Medellin, Colombia, between 2004 and 2009 and aimed at unraveling the underlying molecular mechanisms that explain the correlation between QRDR-A mutations and LVX resistance phenotype. We tested 104 MDR isolates for their susceptibility to OFX, MFX, and LVX. Resistance to OFX was encountered in 10 (9.6%) of the isolates among which 8 (7.7%) were also resistant to LVX and 6 (5.7%) to MFX. Four isolates resistant to the 3 FQ were harboring the Asp94Gly substitution, whilst 2 other isolates resistant to OFX and LVX presented the Ala90Val mutation. No mutations were found in the QRDR-B region. The molecular modeling of the interaction between LVX and the DNA-DNA gyrase complex indicates that the loss of an acetyl group in the Asp94Gly mutation removes the acid base interaction with LVX necessary for the quinolone activity. The Ala90Val mutation that substitutes a methyl for an isopropyl group induces a steric modification that blocks the LVX access to the gyrase catalytic site.

scholarly journals Issues of Tuberculosis Drug-Resistance in Kharkiv Region and in Ukraine

2019 ◽  
pp. 24-28
Author(s):  
O.S. Shevchenko ◽  
O.O. Pohorielova
Keyword(s):  
Drug Resistance ◽  
Statistical Processing ◽  
Multidrug Resistant ◽  
Study Data ◽  
Drug Resistant ◽  
Drug Resistant Tuberculosis ◽  
Resistant Tuberculosis ◽  
Extensively Drug Resistant ◽  
Mdr Tb ◽  
Microsoft Office

Background. Multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis remain severe epidemic problems in the world. That’s why the purpose of our study was to investigate the dynamics of the incidence of multidrug-resistant and extensively drug-resistant tuberculosis, the structure of cases and the effectiveness of treatment in this category of patients in the Kharkiv region and in Ukraine. Materials and methods. To perform the study, data from reporting forms No. 4-2 (TB 07 – MDR TB), No. 8-6 (TB 08) and data from analytical and statistical reference books “Tuberculosis in Ukraine” were used. Statistical processing of information was carried out using Statistica 7.0, Microsoft Office Excel 2007. Results. We found a relatively consistently high incidence rate, prevalence of tuberculosis recurrences among patients with drug-resistant tuberculosis, an increase in the proportion of extensively-drug resistance in patients with treatment failure and interrupted treatment, and low effectiveness of treatment of multidrug-resistant and extensively drug-resistant tuberculosis in patients with repeated cases of treatment. Conclusions. The obtained data once again emphasizes the need for the selection of adequate schemes for antituberculosis chemotherapy and control of anti-tuberculosis drugs.

scholarly journals Whole genomic sequencing as a tool for diagnosis of drug and multidrug-resistance tuberculosis in an endemic region in Mexico

2019 ◽  
Author(s):  
Carlos Francisco Madrazo-Moya ◽  
Irving Cancino-Muñoz ◽  
Betzaida Cuevas-Cordoba ◽  
Vanessa Gonzalez-Covarrubias ◽  
Martín Barbosa-Amezcua ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Multidrug Resistance ◽  
Multidrug Resistant ◽  
Genetic Distances ◽  
Clinical Isolates ◽  
Epidemiological Surveillance ◽  
Drug Resistant ◽  
Second Line ◽  
Endemic Region ◽  
Phenotypic Profile

AbstractBackgroundWhole genome sequencing (WGS) has been proposed as a tool for diagnosing drug resistance in tuberculosis. However, reports of its effectiveness in endemic countries with important numbers of drug resistance are scarce. The goal of this study was to evaluate the effectiveness of this procedure in isolates from a tuberculosis endemic region in Mexico.MethodsWGS analysis was performed in 81 tuberculosis positive clinical isolates with a known phenotypic profile of resistance against first-line drugs (isoniazid, rifampin, ethambutol, pyrazinamide and streptomycin). Mutations related to drug resistance were identified for each isolate; drug resistant genotypes were predicted and compared with the phenotypic profile. Genotypes and transmission clusters based on genetic distances were also characterized.FindingsPrediction by WGS analysis of resistance against isoniazid, rifampicin, ethambutol, pyrazinamide and streptomycin showed sensitivity values of 84%, 96%, 71%, 75% and 29%, while specificity values were 100%, 94%, 90%, 90% and 98%, respectively. Prediction of multidrug resistance showed a sensitivity of 89% and specificity of 97%. Moreover, WGS analysis revealed polymorphisms related to second-line drug resistance, enabling classification of eight and two clinical isolates as pre- and extreme drug-resistant cases, respectively.Four lineages were identified in the population (L1, L2, L3 and L4). The most frequent of these was L4, which included 90% (77) of the isolates. Six transmission clusters were identified; the most frequent was TC6, which included 13 isolates with a L4.1.1 and a predominantly multidrug-resistant condition.ConclusionThe results illustrate the utility of WGS for establishing the potential for prediction of resistance against first and second line drugs in isolates of tuberculosis from the region. They also demonstrate the feasibility of this procedure for use as a tool to support the epidemiological surveillance of drug- and multidrug-resistant tuberculosis.

scholarly journals Drug Resistance Mechanisms in Tuberculosis

2020 ◽  
Author(s):  
Lanfranco Fattorini ◽  
Angelo Iacobino ◽  
Federico Giannoni
Keyword(s):  
Drug Resistance ◽  
Molecular Mechanisms ◽  
Drug Distribution ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Diagnostic Methods ◽  
Drug Resistant ◽  
Resistance Development ◽  
Intrinsic Drug Resistance ◽  
Incident Cases

The increased incidence of multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb) strains, defined as resistant to at least isoniazid and rifampin, the two highly bactericidal first-line drugs, is a major concern for tuberculosis (TB) control. The worldwide estimate of almost half a million incident cases of MDR/rifampin-resistant TB, is causing increasing concern. In this view, it is important to continuously update the knowledge on the mechanisms involved in the development of drug-resistant TB. Clinical, biological and microbiological reasons account for the generation of resistance, including: (i) nonadherence of patients to their therapy, and/or errors of physicians in therapy management, (ii) complexity and poor vascularization of granulomatous lesions, which obstruct drug distribution to some sites, resulting in resistance development, (iii) intrinsic drug resistance of tubercle bacilli, (iv) formation of non-replicating, drug-tolerant bacilli inside the granulomas, (v) development of mutations in Mtb genes, which are the most important molecular mechanisms of resistance. Here, a piece of information on the interplay of these factors is provided, to facilitate the clinical and microbiological management of drug-resistant TB at the global level, with attention also to the most recent diagnostic methods.

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