scholarly journals Advanced Molecular Detection of Malarone Resistance

2016 ◽  
Vol 60 (6) ◽  
pp. 3821-3823 ◽  
Author(s):  
Eldin Talundzic ◽  
Mateusz M. Plucinski ◽  
Shweta Biliya ◽  
Luciana M. Silva-Flannery ◽  
Paul M. Arguin ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Treatment Failure ◽  
Molecular Detection ◽  
Treatment Guidelines ◽  
Malaria Treatment ◽  
Drug Resistant ◽  
Accurate Treatment ◽  
Generation Sequencing ◽  
Rapid Emergence ◽  
Selection Of

The rapid emergence of drug-resistant malaria parasites during the course of an infection remains a major challenge for providing accurate treatment guidelines. This is particularly important in cases of malaria treatment failure. Using a previously well-characterized case of malaria treatment failure, we show the utility of using next-generation sequencing for early detection of the rise and selection of a previously reported atovaquone-proguanil (malarone) drug resistance-associated mutation.

scholarly journals A microfluidic device enabling drug resistance analysis of leukemia cells via coupled dielectrophoretic detection and impedimetric counting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yağmur Demircan Yalçın ◽  
Taylan Berkin Töral ◽  
Sertan Sukas ◽  
Ender Yıldırım ◽  
Özge Zorlu ◽  
...  
Keyword(s):  
Drug Resistance ◽  
K562 Cells ◽  
Leukemia Cells ◽  
Drug Resistant ◽  
Wild Type ◽  
Gene Expressions ◽  
Before And After ◽  
The Difference ◽  
Selection Of ◽  
Resistant Cells

AbstractWe report the development of a lab-on-a-chip system, that facilitates coupled dielectrophoretic detection (DEP-D) and impedimetric counting (IM-C), for investigating drug resistance in K562 and CCRF-CEM leukemia cells without (immuno) labeling. Two IM-C units were placed upstream and downstream of the DEP-D unit for enumeration, respectively, before and after the cells were treated in DEP-D unit, where the difference in cell count gave the total number of trapped cells based on their DEP characteristics. Conductivity of the running buffer was matched the conductivity of cytoplasm of wild type K562 and CCRF-CEM cells. Results showed that DEP responses of drug resistant and wild type K562 cells were statistically discriminative (at p = 0.05 level) at 200 mS/m buffer conductivity and at 8.6 MHz working frequency of DEP-D unit. For CCRF-CEM cells, conductivity and frequency values were 160 mS/m and 6.2 MHz, respectively. Our approach enabled discrimination of resistant cells in a group by setting up a threshold provided by the conductivity of running buffer. Subsequent selection of drug resistant cells can be applied to investigate variations in gene expressions and occurrence of mutations related to drug resistance.

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.

scholarly journals Relationship between Ceftolozane-Tazobactam Exposure and Drug Resistance Amplification in a Hollow-Fiber Infection Model

2013 ◽  
Vol 57 (9) ◽  
pp. 4134-4138 ◽  
Author(s):  
Brian VanScoy ◽  
Rodrigo E. Mendes ◽  
Mariana Castanheira ◽  
Jennifer McCauley ◽  
Sujata M. Bhavnani ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Hollow Fiber ◽  
Drug Exposure ◽  
Resistant Bacteria ◽  
Infection Model ◽  
Drug Resistant ◽  
Dose Ratio ◽  
Bacterial Drug Resistance ◽  
Dosing Regimens ◽  
Selection Of

ABSTRACTIn an era of rapidly emerging antimicrobial-resistant bacteria, it is critical to understand the importance of the relationships among drug exposure, duration of therapy, and selection of drug resistance. Herein we describe the results of studies designed to determine the ceftolozane-tazobactam exposure necessary to prevent the amplification of drug-resistant bacterial subpopulations in a hollow-fiber infection model. The challenge isolate was a CTX-M-15-producingEscherichia coliisolate genetically engineered to transcribe a moderate level ofblaCTX-M-15. This organism'sblaCTX-M-15transcription level was confirmed by relative quantitative reverse transcription-PCR (qRT-PCR), β-lactamase hydrolytic assays, and a ceftolozane MIC value of 16 mg/liter. In these studies, the experimental duration (10 days), ceftolozane-tazobactam dose ratio (2:1), and dosing interval (every 8 h) were selected to approximate those expected to be used clinically. The ceftolozane-tazobactam doses studied ranged from 125-62.5 to 1,500-750 mg. Negative- and positive-control arms included no treatment and piperacillin-tazobactam at 4.5 g every 6 h, respectively. An inverted-U-shaped function best described the relationship between bacterial drug resistance amplification and drug exposure. The least- and most-intensive ceftolozane-tazobactam dosing regimens, i.e., 125-62.5, 750-375, 1,000-500, and 1,500-750 mg, did not amplify drug resistance, while drug resistance amplification was observed with intermediate-intensity dosing regimens (250-125 and 500-250 mg). For the intermediate-intensity ceftolozane-tazobactam dosing regimens, the drug-resistant subpopulation became the dominant population by days 4 to 6. The more-intensive ceftolozane-tazobactam dosing regimens (750-375, 1,000-500, and 1,500-750 mg) not only prevented drug resistance amplification but also virtually sterilized the model system. These data support the selection of ceftolozane-tazobactam dosing regimens that minimize the potential for on-therapy drug resistance amplification.

scholarly journals Relationship between Ceftolozane-Tazobactam Exposure and Selection for Pseudomonas aeruginosa Resistance in a Hollow-Fiber Infection Model

2014 ◽  
Vol 58 (10) ◽  
pp. 6024-6031 ◽  
Author(s):  
Brian D. VanScoy ◽  
Rodrigo E. Mendes ◽  
Mariana Castanheira ◽  
Jennifer McCauley ◽  
Sujata M. Bhavnani ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Infection Model ◽  
Drug Resistant ◽  
Wild Type ◽  
Resistance Selection ◽  
Atcc Strain ◽  
Dosing Regimens ◽  
Selection For ◽  
The Relationship ◽  
Selection Of

ABSTRACTIt is important to understand the relationship between antibiotic exposure and the selection of drug resistance in the context of therapy exposure. We sought to identify the ceftolozane-tazobactam exposure necessary to prevent the amplification of drug-resistant bacterial subpopulations in a hollow-fiber infection model. TwoPseudomonas aeruginosachallenge isolates were selected for study, a wild-type ATCC strain (ceftolozane-tazobactam MIC, 0.5 mg/liter) and a clinical isolate (ceftolozane-tazobactam MIC, 4 mg/liter). The experiment duration was 10 days, and the ceftolozane-tazobactam dose ratio (2:1) and dosing interval (every 8 h) were selected to approximate those expected to be used clinically. The studied ceftolozane-tazobactam dosing regimens ranged from 62.5/31.25 to 2,000/1,000 mg per dose in step fold dilutions. Negative-control arms included no treatment and tazobactam at 500 mg every 8 h. Positive-control arms included ceftolozane at 1 g every 8 h and piperacillin-tazobactam dosed at 4.5 g every 6 h. For the wild-type ATCC strain, resistance was not selected by any ceftolozane-tazobactam regimen evaluated. For the clinical isolate, an inverted-U-shaped function best described the relationship between the amplification of a drug-resistant subpopulation and drug exposure. The least (62.5/31.25 mg) and most (2,000/1,000 mg) intensive ceftolozane-tazobactam dosing regimens did not select for drug resistance. Drug resistance selection was observed with intermediately intensive dosing regimens (125/62.5 through 1,000/500 mg). For the intermediately intensive ceftolozane-tazobactam dosing regimens, the duration until the selection for drug resistance increased with dose regimen intensity. These data support the selection of ceftolozane-tazobactam dosing regimens that minimize the potential for on-therapy drug resistance selection.

scholarly journals Determinants of Multi-drug resistant Tuberculosis in four treatment centers of Eastern Amhara, Ethiopia: A case-control study

2021 ◽  
Vol 15 (05) ◽  
pp. 687-695
Author(s):  
Nuredin Oumer ◽  
Desta Debalkie Atnafu ◽  
Getasew Taddesse Worku ◽  
Asmamaw Ketemaw Tsehay
Keyword(s):  
Drug Resistance ◽  
Treatment Failure ◽  
Case Control Study ◽  
Case Control ◽  
Tuberculosis Treatment ◽  
Multi Drug Resistance ◽  
Drug Resistant ◽  
Tuberculosis Patients ◽  
History Of ◽  
Control Study

Introduction: Tuberculosis is the major global burden of disease contributing about 2% of the global challenges. Poor tuberculosis treatment increased risk of multi-drug resistance tuberculosis occurence. Thus, we aimed to identify determinants of mult-drug resistant tuberclosis in treatment centers of Eastern Amhara, Ethiopia. Methodology: Facility based unmatched case-control study was employed in East Amhara, Ethiopia. Cases were tuberculosis patients confirmed for mult-drug resistant tuberclosis while controls were tuberculosis patients with confirmed tuberculosis but susceptible to first line drugs. Respondents were selected using simple random sampling technique. Bivariable and multivariable analysis was conducted to identify diterminants at level of statistical significance p < 0.05. Results: We enrolled 450 tuberculosis patients. Rural residents (AOR = 3, 95% CI: 1.4-6.0; p = 0.024), family size greater than five (AOR = 3.7, 95% CI: 1.6–8.6; p = 0.0098), having single room (AOR = 4.1, 95% CI:1.8-9.0; p = 0.027), room without window (AOR = 3.8, 95% CI: 1.6-8.5); p = 0.043), contact history of known mult-drug resistant tuberclosis patient (AOR = 5.1, 95% CI: 2.2-12.0; p = 0.02), history of tuberculosis treatment (AOR = 5.7, 95%CI: 2.6-12.9; p = 0.008), window opening practice (AOR = 3.7, 95% CI: 1.4-9.8; p = 0.005), tuberculosis treatment failure (AOR = 7.3, 95% CI: 5.2-7.8; p = 0.035) and tuberculosis relapse (AOR = 5,95% CI: 1.6-15.2; p = 0.019) were determinants of mult-drug resistant tuberclosis. Conclusions: Socio-demographic (residence, family size), environmental (number of rooms, number of windows in a room, opening window practice) and clinical (history of tuberculosis treatment, treatment failure and having contact with known tuberculosis patient) variables were the identified determinants for increased multi-drug resistance tuberculosis.

scholarly journals Within-Host Selection of Drug Resistance in a Mouse Model Reveals Dose-Dependent Selection of Atovaquone Resistance Mutations

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Suci Nuralitha ◽  
Lydia S. Murdiyarso ◽  
Josephine E. Siregar ◽  
Din Syafruddin ◽  
Jessica Roelands ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Body Weight ◽  
Host Selection ◽  
Therapeutic Dose ◽  
Critical Role ◽  
Malaria Treatment ◽  
Resistance Mutations ◽  
Content Type ◽  
Number Of Treatment ◽  
Selection Of

ABSTRACT The evolutionary selection of malaria parasites within an individual host plays a critical role in the emergence of drug resistance. We have compared the selection of atovaquone resistance mutants in mouse models reflecting two different causes of failure of malaria treatment, an inadequate subtherapeutic dose and an incomplete therapeutic dose. The two models are based on cycles of insufficient treatment of Plasmodium berghei-infected mice: repeated inadequate treatment associated with a subtherapeutic dose (RIaT) (0.1 mg kg−1 of body weight) and repeated incomplete treatment with a therapeutic dose (RIcT) (14.4 mg kg−1 of body weight). The number of treatment cycles for the development of a stable resistance phenotype during RIaT was 2.00 ± 0.00 cycles (n = 9), which is not statistically different from that during RIcT (2.57 ± 0.85 cycles; combined n = 14; P = 0.0591). All mutations underlying atovaquone resistance selected by RIaT (M133I, T142N, and L144S) were found to be in the Qo1 (quinone binding 1) domain of the mitochondrial cytochrome b gene, in contrast to those selected by RIcT (Y268N/C, L271V, K272R, and V284F) in the Qo2 domain or its neighboring sixth transmembrane region. Exposure of mixed populations of resistant parasites from RIaT to the higher therapeutic dose of RIcT revealed further insights into the dynamics of within-host selection of resistance to antimalarial drugs. These results suggest that both inadequate subtherapeutic doses and incomplete therapeutic doses in malaria treatment pose similar threats to the emergence of drug resistance. RIcT and RIaT could be developed as useful tools to predict the potential emergence of resistance to newly introduced and less-understood antimalarials.

Tumor Evolutionary Principles: How Intratumor Heterogeneity Influences Cancer Treatment and Outcome

2016 ◽  
pp. e141-e149 ◽  
Author(s):  
Subramanian Venkatesan ◽  
Charles Swanton
Keyword(s):  
Drug Resistance ◽  
Clinical Trials ◽  
Advanced Disease ◽  
Phylogenetic Reconstruction ◽  
Cancer Therapeutics ◽  
Therapeutic Strategies ◽  
Intratumor Heterogeneity ◽  
Cancer Evolution ◽  
Generation Sequencing ◽  
Selection Of

Recent studies have shown that intratumor heterogeneity contributes to drug resistance in advanced disease. Intratumor heterogeneity may foster the selection of a resistant subclone, sometimes detectable prior to treatment. Next-generation sequencing is enabling the phylogenetic reconstruction of a cancer's life history and has revealed different modes of cancer evolution. These studies have shown that cancer evolution is not always stochastic and has certain constraints. Consideration of cancer evolution may enable the better design of clinical trials and cancer therapeutics. In this review, we summarize the different modes of cancer evolution and how this might impact clinical outcomes. Furthermore, we will discuss several therapeutic strategies for managing emergent intratumor heterogeneity.

scholarly journals Adaptation Through Lifestyle Switching Sculpts the Fitness Landscape of Evolving Populations: Implications for the Selection of Drug-Resistant Bacteria at Low Drug Pressures

Genetics ◽  
2019 ◽  
Vol 211 (3) ◽  
pp. 1029-1044 ◽  
Author(s):  
Nishad Matange ◽  
Sushmitha Hegde ◽  
Swapnil Bodkhe
Keyword(s):  
Drug Resistance ◽  
Drug Exposure ◽  
Fitness Landscape ◽  
Rifampicin Resistance ◽  
Resistant Bacteria ◽  
Type I ◽  
Drug Resistant ◽  
The Impact ◽  
Selection Of ◽  
Evolving Populations

Novel genotypes evolve under selection through mutations in pre-existing genes. However, mutations have pleiotropic phenotypic effects that influence the fitness of emerging genotypes in complex ways. The evolution of antimicrobial resistance is mediated by selection of mutations in genes coding for antibiotic-target proteins. Drug-resistance is commonly associated with a fitness cost due to the impact of resistance-conferring mutations on protein function and/or stability. These costs are expected to prohibit the selection of drug-resistant mutations at low drug pressures. Using laboratory evolution of rifampicin resistance in Escherichia coli, we show that when exposed intermittently to low concentration (0.1 × minimal inhibitory concentration) of rifampicin, the evolution of canonical drug resistance was indeed unfavorable. Instead, these bacterial populations adapted by evolving into small-colony variants that displayed enhanced pellicle-forming ability. This shift in lifestyle from planktonic to pellicle-like was necessary for enhanced fitness at low drug pressures, and was mediated by the genetic activation of the fim operon promoter, which allowed expression of type I fimbriae. Upon continued low drug exposure, these bacteria evolved exclusively into high-level drug-resistant strains through mutations at a limited set of loci within the rifampicin-resistance determining region of the rpoB gene. We show that our results are explained by mutation-specific epistasis, resulting in differential impact of lifestyle switching on the competitive fitness of different rpoB mutations. Thus, lifestyle-alterations that are selected at low selection pressures have the potential to modify the fitness effects of mutations, change the genetic structure, and affect the ultimate fate of evolving populations.

scholarly journals Next-generation sequencing of drug resistant Mycobacterium tuberculosis clinical isolates in low-incidence countries

2020 ◽  
Vol 9 (5-6) ◽  
pp. 773-778
Author(s):  
E. Sodja ◽  
N. Toplak ◽  
S. Koren ◽  
M. Kovač ◽  
S. Truden ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Next Generation Sequencing ◽  
Clinical Samples ◽  
Gene Variants ◽  
Drug Resistant ◽  
Ion Torrent ◽  
Next Generation ◽  
Low Incidence ◽  
Generation Sequencing

Drug resistant tuberculosis (TB), especially multidrug (MDR) and extensively drug-resistant (XDR) TB, is still a serious problem in global TB control. Slovenia and North Macedonia are low-incidence countries with TB incidence rates of 5.4 and 10.4 in 2017, respectively. In both countries, the percentage of drug resistant TB is very low with sporadic cases of MDR-TB. However, global burden of drug-resistant TB continues to increase imposing huge impact on public health systems and strongly stimulating the detection of gene variants related with drug resistance in TB. Next-generation sequencing (NGS) can provide comprehensive analysis of gene variants linked to drug resistance in Mycobacterium tuberculosis. Therefore, the aim of our study was to examine the feasibility of a full-length gene analysis for the drug resistance related genes (inhA, katG, rpoB, embB) using Ion Torrent technology and to compare the NGS results with those obtained from conventional phenotypic drug susceptibility testing (DST) in TB isolates. Between 1996 and 2017, we retrospectively selected 56 TB strains from our National mycobacterial culture collection. Of those, 33 TB isolates from Slovenian patients were isolated from various clinical samples and subjected to phenotypic DST testing in Laboratory for Mycobacteria (University Clinic Golnik, Slovenia). The remaining 23 TB isolates were isolated from Macedonian patients and sent to our laboratory for assistance in phenotypic DST testing. TB strains included were either mono-, poly- or multidrug resistant. For control purposes, we also randomly selected five TB strains susceptible to first-line anti-TB drugs. High concordance between genetic (Ion Torrent technology) and standard phenotypic DST testing for isoniazid, rifampicin and ethambutol was observed, with percent of agreement of 77%, 93.4% and 93.3%, sensitivities of 68.2%, 100% and 100%, and specificities of 100%, 80% and 88.2%, respectively. In conclusion, the genotypic DST using Ion Torrent semiconductor NGS successfully predicted drug resistance with significant shortening of time needed to obtain the resistance profiles from several weeks to just a few days.

scholarly journals Antibiotic Susceptibility Pattern of Mycobacterium tuberculosis

1970 ◽  
Vol 7 (1) ◽  
pp. 33-41
Author(s):  
S Subba ◽  
S Singh ◽  
AR Khagi ◽  
R Tuladhar ◽  
B Lekhak ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Treatment Failure ◽  
Significant Relationship ◽  
Drug Resistant ◽  
Susceptibility Pattern ◽  
Antibiotic Susceptibility Pattern ◽  
Tb Control ◽  
Mdr Tb

Background: The emergence and spread of DR and MDR-TB threat global TB control. The susceptibility patterns of M. tuberculosis isolates against anti-tuberculosis drugs informs an important aspect of TB controls and surveillance and analysis of local rates of TB drug resistance helps in the detection and monitoring of the extent of DR and MDR strains, indicating the quality of TB control in the country. Methods: A cross sectional study was conducted to find out antibiotic susceptibility pattern of Mycobacterium tuberculosis in pulmonary tuberculosis patients at national tuberculosis center. All the samples were stained by auramine fluorochrome method; processed by NaOH Ogawa Method; primary cultured; subcultured in 2% Ogawa media; cultured in drug LJ media and finally results observed and interpreted. Here Drug susceptibility test was done on M. tuberculosis isolate from each patient by Proportion method as standard protocol. Results: Ethambutol (66.10%) was found to be the most effective anti-TB drug according to the susceptibility test followed by RMP (60.33%), SM (59.66%) and INH (41.69%) against M. tuberculosis. Among 45 isolated untreated patients, primary drug resistance was observed in 20%, to two drugs in 17.77%, to three drugs in 11.11%, to four drugs in 6.66% and primary Multi-drug resistant in 22.22%. Among 250 isolated from previous treated patients, acquired resistance to one drug was found in 23.60%, to two drugs in 12.40%, to three drugs in 16.40%, to four drugs in 18.80% an acquired Multi-drug resistant in 37.20%. Among 250 treated 68.40% (n=171) were relapse,18% ( n=45) were chronic, 7.6% (n=19) were follow-up, 3.2% (n=8) were defaulter, and 2.8% (n=7) were treatment failure. MDR-TB was found the highest in chronic cases (64.44%) followed by follow-up case (47.36%), treatment failure cases (42.85%), relapse cases (27.48%) and default cases (12.5%). A statistical analysis reveals significant relationship between prior history of treatment and the development of drug resistance. However, no significant relationship between age and sex with the emergence of drug resistance isolates. Conclusion: MDR-TB was found the highest in chronic cases (64.44%) followed by follow-up case (47.36%), treatment failure cases (42.85%), relapse cases (27.48%) and Default cases (12.5%). Key words: multi drug, relapse, resistant, sensitivity, tuberculosis   DOI: 10.3126/jnhrc.v7i1.2277 Journal of Nepal Health Research Council Vol. 7, No. 1, 2009 April 33-41

Sign in / Sign up

Export Citation Format

Share Document