Role of embB Codon 306 Mutations in Mycobacterium tuberculosis Revisited: a Novel Association with Broad Drug Resistance and IS6110 Clustering Rather than Ethambutol Resistance

ABSTRACT Mutations at position 306 of embB (embB306) have been proposed as a marker for ethambutol resistance in Mycobacterium tuberculosis; however, recent reports of embB306 mutations in ethambutol-susceptible isolates caused us to question the biological role of this mutation. We tested 1,020 clinical M. tuberculosis isolates with different drug susceptibility patterns and of different geographical origins for associations between embB306 mutations, drug resistance patterns, and major genetic group. One hundred isolates (10%) contained a mutation in embB306; however, only 55 of these mutants were ethambutol resistant. Mutations in embB306 could not be uniquely associated with any particular type of drug resistance and were found in all three major genetic groups. A striking association was observed between these mutations and resistance to any drug (P < 0.001), and the association between embB306 mutations and resistance to increasing numbers of drugs was highly significant (P < 0.001 for trend). We examined the association between embB306 mutations and IS6110 clustering (as a proxy for transmission) among all drug-resistant isolates. Mutations in embB306 were significantly associated with clustering by univariate analysis (odds ratio, 2.44; P = 0.004). In a multivariate model that also included mutations in katG315, katG463, gyrA95, and kasA269, only mutations in embB306 (odds ratio, 2.14; P = 0.008) and katG315 (odds ratio, 1.99; P = 0.015) were found to be independently associated with clustering. In conclusion, embB306 mutations do not cause classical ethambutol resistance but may predispose M. tuberculosis isolates to the development of resistance to increasing numbers of antibiotics and may increase the ability of drug-resistant isolates to be transmitted between subjects.

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Evaluation the Expression of Efflux Pump Genes “Tap & P55 in Mycobacterium Tuberculosis Clinical Isolates in Fars, Iran

10.21203/rs.3.rs-107737/v1 ◽

2020 ◽

Author(s):

Fardis Khoob ◽

Milad Shahini Shams Abadi ◽

Nahal Hadi ◽

Farzaneh Avazzadeh ◽

Zahra Zarei

Keyword(s):

Drug Resistance ◽

Mycobacterium Tuberculosis ◽

Target Genes ◽

Efflux Pump ◽

Expression Level ◽

Genetic Mutations ◽

Antimicrobial Sensitivity ◽

Probable Role ◽

Tuberculosis Therapy

Abstract BackgroundThe increasing drug resistance in Mycobacterium tuberculosis isolates has become a global problem for tuberculosis therapy programs. Genetic mutations in rifampin (RIF), one of the key drugs in the treatment of tuberculosis are main mechanism of resistant to this drug in M. tuberculosis. Absence of mutation in target genes, other mechanisms such as efflux pump suggests possible role of drug resistant.The objective of this study was to find out mutations in rpoB genes in rifampin resistant isolates and to compare the expression level of tap and p55 efflux pump genes in non mutated isolates, mutated isolates in rpoB genes and susceptible isolates.MethodsIn this study, antimicrobial sensitivity test on first line drugs was performed on 200 M. tuberculosis isolates, obtained from TB center in Shiraz (IRAN) and genetic mutations were evaluated in rpoB gene in RIF resistant isolates by multiplex PCR, followed expression level evaluated by Real-time PCR.Resultsout of the 200 isolates tested, 23 (34.33%) showed resistant to RIF. 12 of 23 RIF resistant isolates have mutation in rpoB gene, and frequency of mutations in codons 516, 526 and 531 were 3 (25%), 4 (33.33%) and 5 (41.67%) respectively. The expression level of tap and p55 genes was considerably higher in resistant isolates which had no mutation compared to the expression level of genes in the isolates which had mutation in target genes.ConclusionThe accumulating data suggest the probable role of efflux pump in M. tuberculosis drug resistance, the validation of data needs further phenotypic assays of these pumps.

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The role of chemotherapy drugs in the formation of resistant populations of mycobacterium tuberculosis

Kazan medical journal ◽

10.17816/kazmj64336 ◽

1980 ◽

Vol 61 (5) ◽

pp. 58

Author(s):

O. A. Irtuganova

Keyword(s):

Drug Resistance ◽

Mycobacterium Tuberculosis ◽

Laboratory Strain ◽

Chemotherapy Drugs ◽

Lowenstein Jensen ◽

Strain H37rv

The aim of the work was to select variants of mycobacterium tuberculosis with altered drug resistance under the influence of anti-tuberculosis drugs. The laboratory strain H37RV was selected by 15 passages of one colony on solid Lowenstein-Jensen medium. In the obtained genetically homogeneous variant of mycobacteria for 1012 individuals, there was not a single one resistant to rifampicin, isoniazid, streptomycin, ethionamide and ethambutol.

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Sensitivities of ciprofloxacin-resistant Mycobacterium tuberculosis clinical isolates to fluoroquinolones: role of mutant DNA gyrase subunits in drug resistance

International Journal of Antimicrobial Agents ◽

10.1016/j.ijantimicag.2012.01.007 ◽

2012 ◽

Vol 39 (5) ◽

pp. 435-439 ◽

Cited By ~ 15

Author(s):

Yasuhiko Suzuki ◽

Chie Nakajima ◽

Aki Tamaru ◽

Hyun Kim ◽

Takashi Matsuba ◽

...

Keyword(s):

Drug Resistance ◽

Mycobacterium Tuberculosis ◽

Dna Gyrase ◽

Clinical Isolates

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Role of Mutations in Dihydrofolate Reductase DfrA (Rv2763c) and Thymidylate Synthase ThyA (Rv2764c) in Mycobacterium tuberculosis Drug Resistance

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00422-10 ◽

2010 ◽

Vol 54 (10) ◽

pp. 4522-4525 ◽

Cited By ~ 5

Author(s):

C. U. Koser ◽

R. N. Veerapen-Pierce ◽

D. K. Summers ◽

J. A. C. Archer ◽

P. Bifani ◽

...

Keyword(s):

Drug Resistance ◽

Mycobacterium Tuberculosis ◽

Dihydrofolate Reductase ◽

Thymidylate Synthase

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Molecular Mechanisms of Drug Resistance in Mycobacterium tuberculosis: Role of Nanoparticles Against Multi-drug-Resistant Tuberculosis (MDR-TB)

NanoBioMedicine ◽

10.1007/978-981-32-9898-9_12 ◽

2020 ◽

pp. 285-314

Author(s):

Amit Singh ◽

Anil Kumar Gupta ◽

Sarman Singh

Keyword(s):

Drug Resistance ◽

Mycobacterium Tuberculosis ◽

Molecular Mechanisms ◽

Drug Resistant ◽

Drug Resistant Tuberculosis ◽

Resistant Tuberculosis ◽

Multi Drug Resistant Tuberculosis ◽

Mdr Tb

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Role of line probe assay in diagnosis and detection of drug resistance in Mycobacterium tuberculosis

International Journal of Research and Development in Pharmacy and Life Sciences ◽

10.21276/ijrdpl.2278-0238.2019.8(2).46-49 ◽

2019 ◽

Vol 8 (2) ◽

pp. 46-49

Author(s):

Phalguni Malhotra ◽

Deepinder Chhina ◽

Veenu Gupta ◽

Akashdeep Singh ◽

Diljot Sandhu

Keyword(s):

Drug Resistance ◽

Mycobacterium Tuberculosis ◽

Line Probe Assay ◽

Probe Assay

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Simultaneous detection of drug-resistant mutations in Mycobacterium tuberculosis and determining their role through in silico docking

Infectious Disorders - Drug Targets ◽

10.2174/1871526520666200318111140 ◽

2020 ◽

Vol 20 ◽

Author(s):

Somanna Nachappa ◽

Sumana Neelambike ◽

Ahmad Sarikhani ◽

Nallur Ramachandra

Keyword(s):

Drug Resistance ◽

Mycobacterium Tuberculosis ◽

Dna Sequencing ◽

In Silico ◽

Sequence Data ◽

Simultaneous Detection ◽

Fluoroquinolone Resistance ◽

Drug Resistant ◽

In Silico Docking

: A molecular method for diagnosis of drug-resistant Tuberculosis is Multiplex allele-specific PCR (MAS-PCR), which is more time-efficient. Also, understanding the role of mutations when translated to protein, in causing resistance helps better drug designing. Aims: To study MAS-PCR in the detection of drug resistance in comparison to DNA sequencing, and understand the mechanism of interaction of drugs with mutant proteins in Mycobacterium tuberculosis. Methods: Detection of drug-resistant mutations using MAS-PCR and validation through DNA sequencing. MAS-PCR targeted four genes, iniA for the drug Ethambutol, rpsL and rrs for Streptomycin, and gyrA for Fluoroquinolone resistance, respectively. Further, the sequence data was analysed and modelled to study the effect on interaction of the anti-TB drug molecule with the target protein using in silico docking. Results: We identified drug-resistant mutations in four out of 95 isolates with one of them carrying a mutation at codon iniA501, two at gyrA94, and one for both iniA501 and gyrA94 using MAS-PCR. DNA sequencing confirmed drug-resistant mutations in only two isolates, whereas two others had mutation adjacent to the target allele. Molecular docking showed Estimated Free Energy of Binding (ΔG) being higher for Fluoroquinolone binding with GyrA D94V mutant. Both, wild and mutant IniA interact with EMB but had no significant effect on binding energy. Conclusions: DNA sequencing-based drug resistance detection of TB is more accurate than MAS-PCR. Understanding the role of mutations in influencing the drug-protein interaction will help in designing effective drug alternatives.

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