scholarly journals Microevolution of Mycobacterium tuberculosis hetero-resistance subpopulations in a patient receiving 27 years of tuberculosis treatment in Germany

2021 ◽  
Author(s):  
Lindsay Sonnenkalb ◽  
Gerald Strohe ◽  
Viola Dreyer ◽  
Sönke Andres ◽  
Doris Hillemann ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Treatment Failure ◽  
Evolutionary Dynamics ◽  
Drug Susceptibility ◽  
Drug Resistant ◽  
Sequencing Data ◽  
Resistance Mutations ◽  
Treatment Regimens ◽  
Resistance Evolution ◽  
Potential Risk Factors

Pre-existing and newly emerging resistant pathogen subpopulations (hetero-resistance) are potential risk factors for treatment failure of multi/extensively drug resistant (MDR/XDR) tuberculosis (TB). Intra-patient evolutionary dynamics of Mycobacterium tuberculosis complex (Mtbc) strains and their implications on treatment outcomes are still not completely understood. Methods To elucidate how Mtbc strains escape therapy, we analysed 13 serial isolates by whole genome sequencing from a German patient. Sequencing data was compared to phenotypic drug susceptibility profiles, and the patient’s collective 27-year treatment history, to further elucidate factors fostering intra-patient resistance evolution. Results The patient endured five distinct TB episodes, ending in resistances to 16 drugs and a nearly untreatable XDR-TB infection. The first isolate obtained, during the patient’s 5th TB episode, presented fixed resistance mutations to seven anti-TB drugs including isoniazid, rifampicin, streptomycin, pyrazinamide, prothionamide, para-aminosalicyclic acid and cycloserin/terizidone. Over the next 13 years a dynamic evolution with co-existing, heterogeneous subpopulations was observed in six out of 13 sequential bacterial isolates. The emergence of drug-resistant subpopulations coincided with frequent changes in treatment regimens, which often included two or less active compounds. This evolutionary arms race between competing sub-populations, ultimately resulted in the fixation of a single XDR variant. Conclusion Our data demonstrates the complex intra-patient microevolution of Mtbc subpopulations during failing MDR/XDR-TB treatment. Designing effective treatment regimens based on rapid detection of (hetero-) resistance is key to avoid resistance development and treatment failure.

scholarly journals Dynamics of Extensive Drug Resistance Evolution of Mycobacterium tuberculosis in a Single Patient During 9 Years of Disease and Treatment

2020 ◽  
Author(s):  
Karin Hjort ◽  
Pontus Jurén ◽  
Juan Carlos Toro ◽  
Sven Hoffner ◽  
Dan I Andersson ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Selection Pressure ◽  
High Capacity ◽  
Single Patient ◽  
Resistance Mutations ◽  
Dynamic Nature ◽  
Treatment Regimens ◽  
Resistance Evolution ◽  
Extensive Drug Resistance ◽  
Susceptibility Tests

Abstract Mycobacterium tuberculosis is one of the hardest to treat bacterial pathogens with a high capacity to develop antibiotic resistance by mutations. Here we have performed whole-genome sequencing of consecutive M. tuberculosis isolates obtained during 9 years from a patient with pulmonary tuberculosis. The infecting strain was isoniazid resistant and during treatment it stepwise accumulated resistance mutations to 8 additional antibiotics. Heteroresistance was common and subpopulations with up to 3 different resistance mutations to the same drug coexisted. Sweeps of different resistant clones dominated the population at different time points, always coupled to resistance mutations coinciding with changes in the treatment regimens. Resistance mutations were predominant and no hitch-hiking, compensatory, or virulence-increasing mutations were detected, showing that the dominant selection pressure was antibiotic treatment. The results highlight the dynamic nature of M. tuberculosis infection, population structure, and resistance evolution and the importance of rapid antibiotic susceptibility tests to battle this pathogen.

scholarly journals Whole-genome sequence analysis and comparisons between drug-resistance mutations and minimum inhibitory concentrations of Mycobacterium tuberculosis isolates causing M/XDR-TB

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244829
Author(s):  
Ditthawat Nonghanphithak ◽  
Orawee Kaewprasert ◽  
Pratchakan Chaiyachat ◽  
Wipa Reechaipichitkul ◽  
Angkana Chaiprasert ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Drug Resistant ◽  
Resistance Mutations ◽  
Tb 34 ◽  
Susceptibility Tests

Drug resistance (DR) remains a major challenge for tuberculosis (TB) control. Whole-genome sequencing (WGS) provides the highest genetic resolution for genotypic drug-susceptibility tests (DST). We compared DST profiles of 60 Mycobacterium tuberculosis isolates which were drug resistant according to agar proportion tests (one poly DR-TB, 34 multidrug-resistant TB and 25 extensively drug-resistant TB). We additionally performed minimum inhibitory concentration (MIC) tests using Sensititre MYCOTBI plates (MYCOTB) and a WGS-based DST. Agreement between WGS-based DST and MYCOTB was high for all drugs except ethambutol (65%) and ethionamide (62%). Isolates harboring the -15 c/t inhA promoter mutation had a significantly lower MIC for isoniazid than did isolates with the katG Ser315Thr mutation (p < 0.001). Similar patterns were seen for ethambutol (embB Gly406Asp vs. embB Met306Ile), streptomycin (gid Gly73Ala vs. rpsL Lys43Arg), moxifloxacin (gyrA Ala90Val vs. gyrA Asp94Gly) and rifabutin (rpoB Asp435Phe/Tyr/Val vs. rpoB Ser450Leu). For genotypic heteroresistance, isolates with lower proportion of mapped read tended to has lower MIC of anti-TB drugs than those with higher proportion. These results emphasize the high applicability of WGS for determination of DR-TB and the association of particular mutations with MIC levels.

scholarly journals Use of fluorescein diacetate (FDA) staining to detect viable Mycobacterium tuberculosis

2012 ◽  
Vol 11 (4) ◽  
pp. 322-330 ◽  
Author(s):  
Shamima Islam ◽  
Farjana Rahman ◽  
Saurab Kisore Munshi ◽  
Jewel Ahmed ◽  
S M Mostafa Kamal ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Treatment Failure ◽  
Medical Science ◽  
Multidrug Resistant ◽  
Fluorescein Diacetate ◽  
Drug Resistant ◽  
Drug Resistant Tuberculosis ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Auramine O

Objective: Drug resistant tuberculosis has long been a common problem prevailing in developing countries including Bangladesh. Present study focused on the rapid identification of live Mycobacterium tuberculosis among treatment failure cases.Materials and Methods: Sputum samples from a total of 100 category-I and category-II treatment failure cases, assumed as multidrug resistant tuberculosis, were studied through fluorescein diacetate (FDA) staining under light emitting diode (LED) fluorescence microscope. Considering culture method as gold standard, we also compared the results of FDA staining with that of auramine O staining.Results: A total of 85% acid-fast bacilli were detected by FDA staining, 82% by auramine O staining and a total of 85% isolates were detected in Lowenstein-Jensen (LJ) culture. The sensitivity of FDA staining (96.47%) was estimated to be slightly higher than that of auramine O staining (91.76%). Moreover,76.47% cases were detected as multidrug resistant tuberculosis (MDR-TB). Conclusion: Taken together, FDA staining method has been proposed to be appropriate for the rapid diagnosis of drug resistant tuberculosis. DOI: http://dx.doi.org/10.3329/bjms.v11i4.12605 Bangladesh Journal of Medical Science Vol. 11 No. 04 Oct’12

scholarly journals Genetic diversity and drug susceptibility patterns of the Mycobacterium tuberculosis complex in Yunnan, China

2019 ◽  
Vol 39 (5) ◽  
Author(s):  
Ruolan Bai ◽  
Shuijing Chi ◽  
Xiaofei Li ◽  
Xiting Dai ◽  
Zhenhua Ji ◽  
...  
Keyword(s):  
Public Health ◽  
Genetic Diversity ◽  
Mycobacterium Tuberculosis ◽  
Public Health Problem ◽  
Drug Susceptibility ◽  
Drug Resistant ◽  
Global Public Health ◽  
High Genetic Diversity ◽  
Dominant Feature ◽  
Mdr Tb

AbstractTuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb) which has been threatening global public health for many years. High genetic diversity is dominant feature of Mtb. Increasing cases of multidrug-resistant (MDR) tuberculosis (MDR-TB) is a serious public health problem to TB control in China. Spontaneous mutations in the Mtb genome can alter proteins which are the target of drugs, making the bacteria drug resistant. The purpose of the present study was to analyze the genotype of Mtb isolates from some areas in Yunnan, China and explore the association between genotypes and MDR-TB. Using spoligotyping, we identified Beijing genotypes, six non-Beijing genotypes and a number of orphan genotypes from 270 Mtb isolates from patients in Yunnan Province during 2014–2016. Of 270 Mtb isolates, 102 clinical Mtb strains were identified as drug-resistant (DR) by drug susceptibility testing (DST), among them, 52 MDR strains. Beijing genotypes occupied the highest MDR proportion (78.85%) followed by the orphan genotypes (15.38%). The characteristics of MDR strains showed high genetic diversity. The results will help to efficiently improve diagnosis and treatment and provide valuable information for Mtb molecular epidemiology.

scholarly journals Distinct Bacterial Pathways Influence the Efficacy of Antibiotics against Mycobacterium tuberculosis

mSystems ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Michelle M. Bellerose ◽  
Megan K. Proulx ◽  
Clare M. Smith ◽  
Richard E. Baker ◽  
Thomas R. Ioerger ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Treatment Outcome ◽  
Mouse Model ◽  
Genetic Variants ◽  
Drug Efficacy ◽  
Drug Susceptibility ◽  
Clinical Isolates ◽  
Drug Resistant ◽  
Bacterial Clearance

ABSTRACT Effective tuberculosis treatment requires at least 6 months of combination therapy. Alterations in the physiological state of the bacterium during infection are thought to reduce drug efficacy and prolong the necessary treatment period, but the nature of these adaptations remain incompletely defined. To identify specific bacterial functions that limit drug effects during infection, we employed a comprehensive genetic screening approach to identify mutants with altered susceptibility to the first-line antibiotics in the mouse model. We identified many mutations that increase the rate of bacterial clearance, suggesting new strategies for accelerating therapy. In addition, the drug-specific effects of these mutations suggested that different antibiotics are limited by distinct factors. Rifampin efficacy is inferred to be limited by cellular permeability, whereas isoniazid is preferentially affected by replication rate. Many mutations that altered bacterial clearance in the mouse model did not have an obvious effect on drug susceptibility using in vitro assays, indicating that these chemical-genetic interactions tend to be specific to the in vivo environment. This observation suggested that a wide variety of natural genetic variants could influence drug efficacy in vivo without altering behavior in standard drug-susceptibility tests. Indeed, mutations in a number of the genes identified in our study are enriched in drug-resistant clinical isolates, identifying genetic variants that may influence treatment outcome. Together, these observations suggest new avenues for improving therapy, as well as the mechanisms of genetic adaptations that limit it. IMPORTANCE Understanding how Mycobacterium tuberculosis survives during antibiotic treatment is necessary to rationally devise more effective tuberculosis (TB) chemotherapy regimens. Using genome-wide mutant fitness profiling and the mouse model of TB, we identified genes that alter antibiotic efficacy specifically in the infection environment and associated several of these genes with natural genetic variants found in drug-resistant clinical isolates. These data suggest strategies for synergistic therapies that accelerate bacterial clearance, and they identify mechanisms of adaptation to drug exposure that could influence treatment outcome.

scholarly journals Genome Sequencing of Polydrug-, Multidrug-, and Extensively Drug-Resistant Mycobacterium tuberculosis Strains from South India

2019 ◽  
Vol 8 (12) ◽  
Author(s):  
Sivakumar Shanmugam ◽  
Narender Kumar ◽  
Dina Nair ◽  
Mohan Natrajan ◽  
Srikanth Prasad Tripathy ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
South India ◽  
Sequence Data ◽  
Whole Genome ◽  
Drug Resistant ◽  
Resistance Mutations ◽  
Content Type ◽  
Extensively Drug Resistant

The genomes of 16 clinical Mycobacterium tuberculosis isolates were subjected to whole-genome sequencing to identify mutations related to resistance to one or more anti-Mycobacterium drugs. The sequence data will help in understanding the genomic characteristics of M. tuberculosis isolates and their resistance mutations prevalent in South India.

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

2005 ◽  
Vol 49 (9) ◽  
pp. 3794-3802 ◽  
Author(s):  
Manzour Hernando Hazbón ◽  
Miriam Bobadilla del Valle ◽  
Marta Inírida Guerrero ◽  
Mandira Varma-Basil ◽  
Ingrid Filliol ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Odds Ratio ◽  
Univariate Analysis ◽  
Drug Susceptibility ◽  
Drug Resistant ◽  
Development Of Resistance ◽  
Resistance Patterns ◽  
Novel Association

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.

scholarly journals Low-Frequency Drug Resistance in HIV-Infected Ugandans on Antiretroviral Treatment Is Associated with Regimen Failure

2016 ◽  
Vol 60 (6) ◽  
pp. 3380-3397 ◽  
Author(s):  
Fred Kyeyune ◽  
Richard M. Gibson ◽  
Immaculate Nankya ◽  
Colin Venner ◽  
Samar Metha ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Treatment Failure ◽  
Sanger Sequencing ◽  
Antiretroviral Treatment ◽  
Low Frequency ◽  
Drug Resistant ◽  
Viral Quasispecies ◽  
Resistance Mutations ◽  
Drug Resistance Mutations ◽  
Hiv 1

Most patients failing antiretroviral treatment in Uganda continue to fail their treatment regimen even if a dominant drug-resistant HIV-1 genotype is not detected. In a recent retrospective study, we observed that approximately 30% of HIV-infected individuals in the Joint Clinical Research Centre (Kampala, Uganda) experienced virologic failure with a susceptible HIV-1 genotype based on standard Sanger sequencing. Selection of minority drug-resistant HIV-1 variants (not detectable by Sanger sequencing) under antiretroviral therapy pressure can lead to a shift in the viral quasispecies distribution, becoming dominant members of the virus population and eventually causing treatment failure. Here, we used a novel HIV-1 genotyping assay based on deep sequencing (DeepGen) to quantify low-level drug-resistant HIV-1 variants in 33 patients failing a first-line antiretroviral treatment regimen in the absence of drug-resistant mutations, as screened by standard population-based Sanger sequencing. Using this sensitive assay, we observed that 64% (21/33) of these individuals had low-frequency (or minority) drug-resistant variants in the intrapatient HIV-1 population, which correlated with treatment failure. Moreover, the presence of these minority HIV-1 variants was associated with higher intrapatient HIV-1 diversity, suggesting a dynamic selection or fading of drug-resistant HIV-1 variants from the viral quasispecies in the presence or absence of drug pressure, respectively. This study identified low-frequency HIV drug resistance mutations by deep sequencing in Ugandan patients failing antiretroviral treatment but lacking dominant drug resistance mutations as determined by Sanger sequencing methods. We showed that these low-abundance drug-resistant viruses could have significant consequences for clinical outcomes, especially if treatment is not modified based on a susceptible HIV-1 genotype by Sanger sequencing. Therefore, we propose to make clinical decisions using more sensitive methods to detect minority HIV-1 variants.

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