<i>Mycobacterium tuberculosis embB</i>
            Codon 306 Mutations Confer Moderately Increased Resistance to Ethambutol In Vitro and In Vivo

Plinke, Claudia; Walter, Kerstin; Aly, Sahar; Ehlers, Stefan; Niemann, Stefan

doi:10.1128/aac.00007-10

Cited by 34 publications

(28 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has also been shown that there is a narrow range between the MICs of EMB-susceptible and EMBresistant isolates of M. tuberculosis (15,47). Some mutations, e.g., the M306I substitution, give rise to a modest increase in the MIC (37,44,52), which may explain why this particular mutation was found in so many EMB-susceptible isolates in this study. It is likely that the EMB MIC increases only moderately for the embB A313V substitution, as we detected it in a phenotypically resistant isolate, and others have found it in EMB-susceptible isolates (6).…”

Section: Discussionsupporting

confidence: 53%

Detection of First- and Second-Line Drug Resistance in Mycobacterium tuberculosis Clinical Isolates by Pyrosequencing

Engström

Morcillo²,

Imperiale³

et al. 2012

J Clin Microbiol

View full text Add to dashboard Cite

Conventional phenotypic drug susceptibility testing (DST) methods for Mycobacterium tuberculosis are laborious and very time-consuming. Early detection of drug-resistant tuberculosis (TB) is essential for prevention and control of TB transmission. We have developed a pyrosequencing method for simultaneous detection of mutations associated with resistance to rifampin, isoniazid, ethambutol, amikacin, kanamycin, capreomycin, and ofloxacin. Seven pyrosequencing assays were optimized for following loci: rpoB , katG , embB , rrs , gyrA , and the promoter regions of inhA and eis . The molecular method was evaluated on a panel of 290 clinical isolates of M. tuberculosis . In comparison to phenotypic DST, the pyrosequencing method demonstrated high specificity (100%) and sensitivity (94.6%) for detection of multidrug-resistant M. tuberculosis as well as high specificity (99.3%) and sensitivity (86.9%) for detection of extensively drug-resistant M. tuberculosis . The short turnaround time combined with multilocus sequencing of several isolates in parallel makes pyrosequencing an attractive method for drug resistance screening in M. tuberculosis .

show abstract

Section: Discussionsupporting

confidence: 53%

Detection of First- and Second-Line Drug Resistance in Mycobacterium tuberculosis Clinical Isolates by Pyrosequencing

Engström

Morcillo²,

Imperiale³

et al. 2012

J Clin Microbiol

View full text Add to dashboard Cite

show abstract

“…This mutation has been observed to cause both low-level and high-level resistance to ethambutol and so may lead to a borderline phenotype (21,22). The isolate from patient 15 was phenotypically ethambutol sensitive but had a Q497R mutation in the embB gene, which has previously been associated with sensitivity both in clinical isolates (23) and through the construction of isogenic mutants (24), and so was discounted.…”

Section: Resultsmentioning

confidence: 99%

Rapid Whole-Genome Sequencing of Mycobacterium tuberculosis Isolates Directly from Clinical Samples

et al. 2015

View full text Add to dashboard Cite

The rapid identification of antimicrobial resistance is essential for effective treatment of highly resistant Mycobacterium tuberculosis. Whole-genome sequencing provides comprehensive data on resistance mutations and strain typing for monitoring transmission, but unlike for conventional molecular tests, this has previously been achievable only from cultures of M. tuberculosis. Here we describe a method utilizing biotinylated RNA baits designed specifically for M. tuberculosis DNA to capture full M. tuberculosis genomes directly from infected sputum samples, allowing whole-genome sequencing without the requirement of culture. This was carried out on 24 smear-positive sputum samples, collected from the United Kingdom and Lithuania where a matched culture sample was available, and 2 samples that had failed to grow in culture. M. tuberculosis sequencing data were obtained directly from all 24 smear-positive culture-positive sputa, of which 20 were of high quality (>20؋ depth and >90% of the genome covered). Results were compared with those of conventional molecular and culture-based methods, and high levels of concordance between phenotypical resistance and predicted resistance based on genotype were observed. High-quality sequence data were obtained from one smear-positive culture-negative case. This study demonstrated for the first time the successful and accurate sequencing of M. tuberculosis genomes directly from uncultured sputa. Identification of known resistance mutations within a week of sample receipt offers the prospect for personalized rather than empirical treatment of drug-resistant tuberculosis, including the use of antimicrobial-sparing regimens, leading to improved outcomes.T he global incidence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and totally drug-resistant tuberculosis (TB) has risen over the last decade (1), making it increasingly important to rapidly and accurately detect resistance. The gold standard for antimicrobial resistance testing relies on bacterial culture, which can take upwards of several weeks for Mycobacterium tuberculosis. Molecular tests, such as the Xpert (MTB/RIF) and line probe assays, which can be used directly on sputum have improved identification of MDR M. tuberculosis but are able to identify only limited numbers of specific resistance mutations (2, 3).Whole-genome sequencing (WGS) of bacterial genomes allows simultaneous identification of all known resistance mutations as well as markers with which transmission can be monitored (4). WGS of M. tuberculosis provides resolution superior to that of other current methods such as spoligotyping and mycobacterial interspersed repetitive-unit-variable-number tandemrepeat (MIRU-VNTR) analysis for strain genotyping (5), and its usefulness in defining outbreaks has been demonstrated previously (6-9). Currently, however, WGS of M. tuberculosis requires prior bacterial enrichment by culturing and most outbreak studies have therefore been retrospective (6-8). Recently, WGS of M. tuberculosis has been achieved ...

show abstract

“…These genes are ubiquitous in mycobacteria and have no sequence similarity to any identified protein family in other bacteria. Consequently, the accumulation of mycolic acids due to a lack of arabinan receptors for mycolic acids results in cell death [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Frequency of mutational changes in the embB among the ethambutol-resistant strains of Mycobacterium tuberculosis in Iran

Rezaei

Haeili

Mohajeri

et al. 2016

J Infect Dev Ctries

View full text Add to dashboard Cite

Introduction: Early detection of drug resistant tuberculosis is one of the main priorities of TB control program. Ethambutol (EMB) is a firstline anti-TB drug that is effective for preventing treatment failures caused by Mycobacterium tuberculosis strains that are resistant to other drugs. The aim of this study was to sequence the embB gene to characterize the mutations causing resistance to EMB and to analyze the relationship between bacterial genotype and EMB resistance among M. tuberculosis isolates in Iran. Methodology: A total of 20 M. tuberculosis isolates comprising 10 multidrug-resistant (MDR) and 10 non-MDR isolates, recovered from TB patients in four regions: Tehran, Isfahan, Zahedan, Khorasan, were analyzed. Mutational profiling was performed by amplifying and sequencing the embB gene. Spoligotyping was carried out to characterize the bacterial genotype. Results: Phenotypic EMB resistance was found in 13 strains. Mutations affecting ethambutol resistance-determining region (ERDR) of the embB were identified in 6 of 13 EMB-resistant isolates. The majority of these mutations resulted in amino acid substitution at position 306 (M306V). A novel mutation at codon 366 was identified (S366L) in one isolate. Ural was the most predominant genotype in the studied population. Beijing genotype was associated with both MDR and EMB resistance in which all mutations occurred at codon 306 of the embB gene. Conclusion: A significant association between Beijing genotype and EMB resistance was found, mainly due to mutations at embB306. Results of this study can be used as a basis to develop or improve rapid molecular tests to monitor drug-resistant strains in this country.

show abstract

Mycobacterium tuberculosis embB Codon 306 Mutations Confer Moderately Increased Resistance to Ethambutol In Vitro and In Vivo

Cited by 34 publications

References 28 publications

Detection of First- and Second-Line Drug Resistance in Mycobacterium tuberculosis Clinical Isolates by Pyrosequencing

Detection of First- and Second-Line Drug Resistance in Mycobacterium tuberculosis Clinical Isolates by Pyrosequencing

Rapid Whole-Genome Sequencing of Mycobacterium tuberculosis Isolates Directly from Clinical Samples

Frequency of mutational changes in the embB among the ethambutol-resistant strains of Mycobacterium tuberculosis in Iran

Contact Info

Product

Resources

About