Enhancement of drug susceptibility of multi-drug resistant strains of Mycobacterium tuberculosis by ethambutol and dimethyl sulphoxide

1995 ◽  
Vol 35 (3) ◽  
pp. 381-390 ◽  
Author(s):  
Chinnaswamy Jagannath ◽  
Venkata M. Reddy ◽  
Pattisapu R. J. Gangadharam
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Susceptibility ◽  
Dimethyl Sulphoxide ◽  
Drug Resistant ◽  
Resistant Strains ◽  
Drug Resistant Strains

scholarly journals Morphologic characterization of Mycobacterium tuberculosis circulating strains in a Lisbon hospital.

2013 ◽  
Vol 19 (S4) ◽  
pp. 11-12
Author(s):  
C. Silva ◽  
E. Alverca ◽  
A.P. Alves de Matos ◽  
P.A. Carvalho ◽  
I. Portugal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mycobacterium Tuberculosis ◽  
Cell Envelope ◽  
Drug Susceptibility ◽  
Drug Resistant ◽  
Lowenstein Jensen ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
Surface Figure

Tuberculosis (TB) is one of the major causes of mortality and morbidity worldwide accounting for 3.1 million deaths per year. This disease, caused by Mycobacterium tuberculosis (M. tuberculosis) made a deadly comeback, during the 1990’s, triggered mainly by the emergence of acquired immunodeficiency syndrome (AIDS). More recently, the emergence of multidrug resistant (MDR) and extensively drug resistant (XDR) M. tuberculosis strains, uncovered the most freighting face of this disease an incurable infection with the currently available therapeutic tools. Although Portugal is considered a medium incidence setting, annually are reported MDR and even XDR TB cases. The majority of these cases occur in the Lisbon area and the strains involved are genetically related being known as Lisboa family.In the present work a group of 283 M. tuberculosis isolates collected in a Lisbon hospital during a two years period (2008-2009) were studied. The morphology of colonies grown on Lowenstein-Jensen slants was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) using previously described procedures. The aim of the study was the establishment of a link between mycobacteria drug susceptibility and structure. In the first part of the study approximately 20 isolates, with different drug susceptibility profiles ranging from pan-susceptible to XDR, were grown on Lowenstein-Jensen slants and their morphology was compared. Although all mycobacteria originated rough colonies their size differ with the drug susceptibility profile. The pan-susceptible strains generated larger colonies than drug resistant strains as shown in figure 1.These colonies were then processed for SEM analysis. The results obtained show that mycobacteria surface are distinct in susceptible and drug resistant strains as shown in figure 2.A and B. While drug susceptible mycobacteria have a homogenous surface (Figure 1A), drug resistant bacteria present a heterogeneous surface (Figure 2B) with small protrusions (Fig. 2B inset). In order to evaluate the existence of differences in the ultrastructure of circulating M. tuberculosis strains the colonies were processed and analysed by TEM. For this approach were selected only two isolates: the pan-susceptible R188/09 and the XDR HPV108/09.The results obtained by the analysis of at least 300 bacteria present in non consecutive sections show that mycobacteria cell width (0 350 nm) is similar for both bacteria (Table 1). Nevertheless, their cell length and cell envelope width are significantly different. The XDR strain is shorter (p=0.009) and has a ticker cell envelope (p=0.004) than the pan-susceptible strain. These results are in agreement with those published in the literature.Altogether our data clearly shows the existence of a link between mycobacteria ultrastructure and drug susceptibility. In order to better evaluate these differences a larger number of isolates must be studied. The use of other electron microscopy techniques, such as CEMOVIS, will avoid the formation of undesirable artefacts (e.g. mesosome) produced by dehydration and room temperature sectioning allowing a better characterization of mycobacteria ultrastructure.The authors acknowledge the funding by Fundação para a Ciência e Tecnologia (SFRH/BD/73579/2010, C2008-C2008_P2 and PEst-OE/CTM-UI0084/2011 grants.)

Evaluation of efflux pump gene expression among drug susceptible and drug resistant strains of Mycobacterium tuberculosis from Iran

2015 ◽  
Vol 36 ◽  
pp. 23-26 ◽  
Author(s):  
Jalil Kardan Yamchi ◽  
Mehri Haeili ◽  
Seifu Gizaw Feyisa ◽  
Hossein Kazemian ◽  
Abdolrazagh Hashemi Shahraki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mycobacterium Tuberculosis ◽  
Efflux Pump ◽  
Drug Resistant ◽  
Resistant Strains ◽  
Drug Resistant Strains

Mycobacterium tuberculosis topoisomerases and EthR as the targets for new anti-TB drugs development

2019 ◽  
Vol 11 (16) ◽  
pp. 2193-2203
Author(s):  
Rafal Sawicki ◽  
Grazyna Ginalska
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Short Review ◽  
Drug Resistant ◽  
Dna Topoisomerases ◽  
Antituberculosis Drugs ◽  
Drug Candidates ◽  
Computational Sciences ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
New Strategies

The significant increase in the detection of drug-resistant strains of Mycobacterium tuberculosis caused an urgent need for the discovery new antituberculosis drugs. Development of bioinformatics and computational sciences enabled the progress of new strategies leading to design, discovery and identification of a series of interesting drug candidates. In this short review, we would like to present recently discovered compounds targeting important mycobacterial proteins: DNA topoisomerases and the transcriptional repressor of EthA monooxygenase – EthR.

scholarly journals In Vitro Activity and MIC of Sitafloxacin against Multidrug-Resistant and Extensively Drug-Resistant Mycobacterium tuberculosis Isolated in Thailand

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Manoon Leechawengwongs ◽  
Therdsak Prammananan ◽  
Sarinya Jaitrong ◽  
Pamaree Billamas ◽  
Nampueng Makhao ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Critical Concentration ◽  
Multidrug Resistant ◽  
Quinolone Resistance ◽  
Drug Resistant ◽  
Content Type ◽  
Extensively Drug Resistant ◽  
Resistant Strains ◽  
Drug Resistant Strains

ABSTRACT New fluoroquinolones (FQs) have been shown to be more active against drug-resistant Mycobacterium tuberculosis strains than early FQs, such as ofloxacin. Sitafloxacin (STFX) is a new fluoroquinolone with in vitro activity against a broad range of bacteria, including M. tuberculosis. This study aimed to determine the in vitro activity of STFX against all groups of drug-resistant strains, including multidrug-resistant M. tuberculosis (MDR M. tuberculosis), MDR M. tuberculosis with quinolone resistance (pre-XDR), and extensively drug-resistant (XDR) strains. A total of 374 drug-resistant M. tuberculosis strains were tested for drug susceptibility by the conventional proportion method, and 95 strains were randomly submitted for MIC determination using the microplate alamarBlue assay (MABA). The results revealed that all the drug-resistant strains were susceptible to STFX at a critical concentration of 2 μg/ml. Determination of the MIC90s of the strains showed different MIC levels; MDR M. tuberculosis strains had a MIC90 of 0.0625 μg/ml, whereas pre-XDR and XDR M. tuberculosis strains had identical MIC90s of 0.5 μg/ml. Common mutations within the quinolone resistance-determining region (QRDR) of gyrA and/or gyrB did not confer resistance to STFX, except that double mutations of GyrA at Ala90Val and Asp94Ala were found in strains with a MIC of 1.0 μg/ml. The results indicated that STFX had potent in vitro activity against all the groups of drug-resistant M. tuberculosis strains and should be considered a new repurposed drug for treatment of multidrug-resistant and extensively drug-resistant TB.

scholarly journals GENETIC DIVERSITY OF DRUG RESISTANT STRAINS OF MYCOBACTERIUM TUBERCULOSIS IN OMSK REGION

2017 ◽  
Vol 95 (7) ◽  
pp. 33-39
Author(s):  
O. A. Pasechnik ◽  
◽  
A. M. Dymova ◽  
V. L. Stasenko ◽  
M. P. Tatarintseva ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Mycobacterium Tuberculosis ◽  
Drug Resistant ◽  
Resistant Strains ◽  
Drug Resistant Strains

scholarly journals Snapshot of Mycobacterium tuberculosis Phylogenetics from an Indian State of Arunachal Pradesh Bordering China

2021 ◽  
Author(s):  
Rashmi S Mudliar ◽  
Umay Kulsum ◽  
Syed Beenish Rufai ◽  
Mika Umpo ◽  
Moi Nyori ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Drug Resistant ◽  
Second Line ◽  
Arunachal Pradesh ◽  
Tuberculosis Programme ◽  
Indian State ◽  
Northeastern State ◽  
Resistant Strains ◽  
Drug Resistant Strains

Uncontrolled transmission of Mycobacterium tuberculosis (M. tuberculosis, MTB) drug resistant strains is a challenge to control efforts of global tuberculosis programme. Due to increasing multi-drug resistant (MDR) cases in Arunachal Pradesh, a northeastern state of India, the tracking and tracing of these resistant MTB strains is crucial for infection control and spread of drug resistance. This study aims to correlate the phenotypic DST, genomic DST (gDST) and phylogenetic analysis of MDR-MTB strains in the region. Of total 200 suspected MDR-MTB isolates, 125(62.5%) were identified as MTB. MGIT-960 SIRE DST detected 71/125(56.8%) isolates as MDR/RR-MTB of which 22(30.9%) were detected resistant to second line drugs. Whole genome sequencing of 65 isolates and their gDST found Ser315Thr mutation in katG (35/45;77.8%) and Ser531Leu mutation in rpoB (21/41;51.2%) associated with drug resistance. SNP barcoding categorized the dataset with Lineage2 (41;63.1%) being predominant followed by Lineage3 (10;15.4%), Lineage1 (8;12.3%) and Lineage4 (6;9.2%) respectively. Phylogenetic assignment by cgMLST gave insights of two Beijing sub-lineages viz; 2.2.1 (SNP difference < 19) and 2.2.1.2 (SNP difference < 9) associated with recent ongoing transmission in Arunachal Pradesh. This study provides first insight in identifying the ongoing transmission of two virulent Beijing sub-lineages associated with TB drug resistance.

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