Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
1.
Heliyon ; 10(6): e27852, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38560672

RESUMO

Antimicrobial peptides (AMPs) have emerged as promising candidates in combating antimicrobial resistance - a growing issue in healthcare. However, to develop AMPs into effective therapeutics, a thorough analysis and extensive investigations are essential. In this study, we employed an in silico approach to design cationic AMPs de novo, followed by their experimental testing. The antibacterial potential of de novo designed cationic AMPs, along with their synergistic properties in combination with conventional antibiotics was examined. Furthermore, the effects of bacterial inoculum density and metabolic state on the antibacterial activity of AMPs were evaluated. Finally, the impact of several potent AMPs on E. coli cell envelope and genomic DNA integrity was determined. Collectively, this comprehensive analysis provides insights into the unique characteristics of cationic AMPs.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38616847

RESUMO

The world health organization's global tuberculosis (TB) report for 2022 identifies TB, with an estimated 1.6 million, as a leading cause of death. The number of new cases has risen since 2020, particularly the number of new drug-resistant cases, estimated at 450,000 in 2021. This is concerning, as treatment of patients with drug resistant TB is complex and may not always be successful. The NIAID TB Portals program is an international consortium with a primary focus on patient centric data collection and analysis for drug resistant TB. The data includes images, their associated radiological findings, clinical records, and socioeconomic information. This work describes a TB Portals' Chest X-ray based image retrieval system which enables precision medicine. An input image is used to retrieve similar images and the associated patient specific information, thus facilitating inspection of outcomes and treatment regimens from comparable patients. Image similarity is defined using clinically relevant biomarkers: gender, age, body mass index (BMI), and the percentage of lung affected per sextant. The biomarkers are predicted using variations of the DenseNet169 convolutional neural network. A multi-task approach is used to predict gender, age and BMI incorporating transfer learning from an initial training on the NIH Clinical Center CXR dataset to the TB portals dataset. The resulting gender AUC, age and BMI mean absolute errors were 0.9854, 4.03years and 1.67kgm2. For the percentage of sextant affected by lesions the mean absolute errors ranged between 7% to 12% with higher error values in the middle and upper sextants which exhibit more variability than the lower sextants. The retrieval system is currently available from https://rap.tbportals.niaid.nih.gov/find_similar_cxr.

3.
Emerg Infect Dis ; 30(4): 831-833, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38526186

RESUMO

In 2021, the World Health Organization recommended new extensively drug-resistant (XDR) and pre-XDR tuberculosis (TB) definitions. In a recent cohort of TB patients in Eastern Europe, we show that XDR TB as currently defined is associated with exceptionally poor treatment outcomes, considerably worse than for the former definition (31% vs. 54% treatment success).


Assuntos
Tuberculose Resistente a Múltiplos Medicamentos , Humanos , Ucrânia/epidemiologia , Moldávia/epidemiologia , Cazaquistão/epidemiologia , Quirguistão/epidemiologia , República da Geórgia/epidemiologia , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia
4.
ACS Omega ; 8(48): 46218-46226, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38075802

RESUMO

Antiviral peptides (AVPs) are bioactive peptides that exhibit the inhibitory activity against viruses through a range of mechanisms. Virus entry inhibitory peptides (VEIPs) make up a specific class of AVPs that can prevent envelope viruses from entering cells. With the growing number of experimentally verified VEIPs, there is an opportunity to use machine learning to predict peptides that inhibit the virus entry. In this paper, we have developed the first target-specific prediction model for the identification of new VEIPs using, along with the peptide sequence characteristics, the attributes of the envelope proteins of the target virus, which overcomes the problem of insufficient data for particular viral strains and improves the predictive ability. The model's performance was evaluated through 10 repeats of 10-fold cross-validation on the training data set, and the results indicate that it can predict VEIPs with 87.33% accuracy and Matthews correlation coefficient (MCC) value of 0.76. The model also performs well on an independent test set with 90.91% accuracy and MCC of 0.81. We have also developed an automatic computational tool that predicts VEIPs, which is freely available at https://dbaasp.org/tools?page=linear-amp-prediction.

5.
Eur J Radiol Open ; 11: 100518, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37808069

RESUMO

Purpose: This study compares performance of Timika Score to standardized, detailed radiologist observations of Chest X rays (CXR) for predicting early infectiousness and subsequent treatment outcome in drug sensitive (DS) or multi-drug resistant (MDR) tuberculosis cases. It seeks improvement in prediction of these clinical events through these additional observations. Method: This is a retrospective study analyzing cases from the NIH/NIAID supported TB Portals database, a large, trans-national, multi-site cohort of primarily drug-resistant tuberculosis patients. We analyzed patient records with sputum microscopy readings, radiologist annotated CXR, and treatment outcome including a matching step on important covariates of age, gender, HIV status, case definition, Body Mass Index (BMI), smoking, drug use, and Timika Score across resistance type for comparison. Results: 2142 patients with tuberculosis infection (374 with poor outcome and 1768 with good treatment outcome) were retrospectively reviewed. Bayesian ANOVA demonstrates radiologist observations did not show greater predictive ability for baseline infectiousness (0.77 and 0.74 probability in DS and MDR respectively); however, the observations provided superior prediction of treatment outcome (0.84 and 0.63 probability in DS and MDR respectively). Estimated lung abnormal area and cavity were identified as important predictors underlying the Timika Score's performance. Conclusions: Timika Score simplifies the usage of baseline CXR for prediction of early infectiousness of the case and shows comparable performance to using detailed, standardized radiologist observations. The score's utility diminishes for treatment outcome prediction and is exceeded by the usage of the detailed observations although prediction performance on treatment outcome decreases especially in MDR TB cases.

6.
Microbiol Spectr ; : e0453122, 2023 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-37671895

RESUMO

Whole-genome sequencing has created a revolution in tuberculosis management by providing a comprehensive picture of the various genetic polymorphisms with unprecedented accuracy. Studies mapping genomic heterogeneity in clinical isolates of Mycobacterium tuberculosis using a whole-genome sequencing approach from high tuberculosis burden countries are underrepresented. We report whole-genome sequencing results of 242 clinical isolates of culture-confirmed M. tuberculosis isolates from tuberculosis patients referred to a tertiary care hospital in Southern India. Phylogenetic analysis revealed that the isolates in our study belonged to five different lineages, with Indo-Oceanic (lineage 1, n = 122) and East-African Indian (lineage 3, n = 80) being the most prevalent. We report several mutations in genes conferring resistance to first and second line antitubercular drugs including the genes rpoB, katG, ahpC, inhA, fabG1, embB, pncA, rpsL, rrs, and gyrA. The majority of these mutations were identified in relatively high proportions in lineage 1. Our study highlights the utility of whole-genome sequencing as a potential supplemental tool to the existing genotypic and phenotypic methods, in providing expedited comprehensive surveillance of mutations that may be associated with antitubercular drug resistance as well as lineage characterization of M. tuberculosis isolates. Further larger-scale whole-genome datasets with linked minimum inhibition concentration testing are imperative for resolving the discrepancies between whole-genome sequencing and phenotypic drug sensitivity testing results and quantifying the level of the resistance associated with the mutations for optimization of antitubercular drug and precise dose selection in clinics. IMPORTANCE Studies mapping genetic heterogeneity of clinical isolates of M. tuberculosis for determining their strain lineage and drug resistance by whole-genome sequencing are limited in high tuberculosis burden settings. We carried out whole-genome sequencing of 242 M. tuberculosis isolates from drug-sensitive and drug-resistant tuberculosis patients, identified and collected as part of the TB Portals Program, to have a comprehensive insight into the genetic diversity of M. tuberculosis in Southern India. We report several genetic variations in M. tuberculosis that may confer resistance to antitubercular drugs. Further wide-scale efforts are required to fully characterize M. tuberculosis genetic diversity at a population level in high tuberculosis burden settings for providing precise tuberculosis treatment.

7.
Brief Bioinform ; 23(4)2022 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-35724561

RESUMO

The evolution of drug-resistant pathogenic microbial species is a major global health concern. Naturally occurring, antimicrobial peptides (AMPs) are considered promising candidates to address antibiotic resistance problems. A variety of computational methods have been developed to accurately predict AMPs. The majority of such methods are not microbial strain specific (MSS): they can predict whether a given peptide is active against some microbe, but cannot accurately calculate whether such peptide would be active against a particular MS. Due to insufficient data on most MS, only a few MSS predictive models have been developed so far. To overcome this problem, we developed a novel approach that allows to improve MSS predictive models (MSSPM), based on properties, computed for AMP sequences and characteristics of genomes, computed for target MS. New models can perform predictions of AMPs for MS that do not have data on peptides tested on them. We tested various types of feature engineering as well as different machine learning (ML) algorithms to compare the predictive abilities of resulting models. Among the ML algorithms, Random Forest and AdaBoost performed best. By using genome characteristics as additional features, the performance for all models increased relative to models relying on AMP sequence-based properties only. Our novel MSS AMP predictor is freely accessible as part of DBAASP database resource at http://dbaasp.org/prediction/genome.


Assuntos
Peptídeos Catiônicos Antimicrobianos , Aprendizado de Máquina , Algoritmos , Peptídeos Catiônicos Antimicrobianos/genética , Bases de Dados Factuais
8.
Tuberculosis (Edinb) ; 133: 102171, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35101846

RESUMO

The TB Portals program is an international collaboration for the collection and dissemination of tuberculosis data from patient cases focused on drug resistance. The central database is a patient-oriented resource containing both patient and pathogen clinical and genomic information. Herein we provide a summary of the pathogen genomic data available through the TB Portals and show one potential application by examining patterns of genomic pairwise distances. Distributions of pairwise distances highlight overall patterns of genome variability within and between Mycobacterium tuberculosis phylogenomic lineages. Closely related isolates (based on whole-genome pairwise distances and time between sample collection dates) from different countries were identified as potential evidence of international transmission of drug-resistant tuberculosis. These high-level views of genomic relatedness provide information that can stimulate hypotheses for further and more detailed research.


Assuntos
Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Tuberculose , Antituberculosos/uso terapêutico , Bases de Dados Factuais , Farmacorresistência Bacteriana Múltipla/genética , Genômica , Humanos , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/genética , Tuberculose/diagnóstico , Tuberculose/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/diagnóstico , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/genética
9.
Nat Commun ; 12(1): 2716, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976135

RESUMO

Polyclonal infections occur when at least two unrelated strains of the same pathogen are detected in an individual. This has been linked to worse clinical outcomes in tuberculosis, as undetected strains with different antibiotic resistance profiles can lead to treatment failure. Here, we examine the amount of polyclonal infections in sputum and surgical resections from patients with tuberculosis in the country of Georgia. For this purpose, we sequence and analyse the genomes of Mycobacterium tuberculosis isolated from the samples, acquired through an observational clinical study (NCT02715271). Access to the lung enhanced the detection of multiple strains (40% of surgery cases) as opposed to just using a sputum sample (0-5% in the general population). We show that polyclonal infections often involve genetically distant strains and can be associated with reversion of the patient's drug susceptibility profile over time. In addition, we find different patterns of genetic diversity within lesions and across patients, including mutational signatures known to be associated with oxidative damage; this suggests that reactive oxygen species may be acting as a selective pressure in the granuloma environment. Our results support the idea that the magnitude of polyclonal infections in high-burden tuberculosis settings is underestimated when only testing sputum samples.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano , Granuloma/patologia , Mycobacterium tuberculosis/genética , Tuberculose Resistente a Múltiplos Medicamentos/patologia , Tuberculose Pulmonar/patologia , Antituberculosos/uso terapêutico , Biópsia , Células Clonais , Estudos de Coortes , Variação Genética , República da Geórgia , Granuloma/tratamento farmacológico , Granuloma/microbiologia , Granuloma/cirurgia , Humanos , Pulmão/microbiologia , Pulmão/patologia , Pulmão/cirurgia , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/patogenicidade , Espécies Reativas de Oxigênio/metabolismo , Escarro/microbiologia , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Tuberculose Resistente a Múltiplos Medicamentos/cirurgia , Tuberculose Pulmonar/tratamento farmacológico , Tuberculose Pulmonar/microbiologia , Tuberculose Pulmonar/cirurgia
10.
PLoS One ; 16(3): e0247906, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33730021

RESUMO

The TB Portals program provides a publicly accessible repository of TB case data containing multi-modal information such as case clinical characteristics, pathogen genomics, and radiomics. The real-world resource contains over 3400 TB cases, primarily drug resistant cases, and CT images with radiologist annotations are available for many of these cases. The breadth of data collected offers a patient-centric view into the etiology of the disease including the temporal context of the available imaging information. Here, we analyze a cohort of new TB cases with available radiologist observations of CTs taken around the time of initial registration of the case into the database and with available follow up to treatment outcome of cured or died. Follow up ranged from 5 weeks to a little over 2 years consistent with the longest treatment regimens for drug resistant TB and cases were registered within the years 2008 to 2019. The radiologist observations were incorporated into machine learning pipelines to test various class balancing strategies on the performance of predictive models. The modeling results support that the radiologist observations are predictive of treatment outcome. Moreover, inferential statistical analysis identifies markers of TB disease spread as having an association with poor treatment outcome including presence of radiologist observations in both lungs, swollen lymph nodes, multiple cavities, and large cavities. While the initial results are promising, further data collection is needed to incorporate methods to mitigate potential confounding such as including additional model covariates or matching cohorts on covariates of interest (e.g. demographics, BMI, comorbidity, TB subtype, etc.). Nonetheless, the preliminary results highlight the utility of the resource for hypothesis generation and exploration of potential biomarkers of TB disease severity and support these additional data collection efforts.


Assuntos
Pulmão/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Tuberculose/diagnóstico por imagem , Antituberculosos/uso terapêutico , Gerenciamento de Dados , Bases de Dados Factuais , Humanos , Aprendizado de Máquina , Radiologistas , Resultado do Tratamento , Tuberculose/tratamento farmacológico
11.
J Mol Biol ; 433(4): 166763, 2021 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-33359098

RESUMO

Mycobacterium tuberculosis (Mtb) infection is among top ten causes of death worldwide, and the number of drug-resistant strains is increasing. The direct interception of human immune signaling molecules by Mtb remains elusive, limiting drug discovery. Oxysterols and secosteroids regulate both innate and adaptive immune responses. Here we report a functional, structural, and bioinformatics study of Mtb enzymes initiating cholesterol catabolism and demonstrated their interrelation with human immunity. We show that these enzymes metabolize human immune oxysterol messengers. Rv2266 - the most potent among them - can also metabolize vitamin D3 (VD3) derivatives. High-resolution structures show common patterns of sterols binding and reveal a site for oxidative attack during catalysis. Finally, we designed a compound that binds and inhibits three studied proteins. The compound shows activity against Mtb H37Rv residing in macrophages. Our findings contribute to molecular understanding of suppression of immunity and suggest that Mtb has its own transformation system resembling the human phase I drug-metabolizing system.


Assuntos
Metabolismo Energético , Interações Hospedeiro-Patógeno , Mycobacterium tuberculosis/imunologia , Tuberculose/imunologia , Tuberculose/metabolismo , 3-Hidroxiesteroide Desidrogenases/química , 3-Hidroxiesteroide Desidrogenases/metabolismo , Catálise , Sistema Enzimático do Citocromo P-450/química , Sistema Enzimático do Citocromo P-450/metabolismo , Ativação Enzimática , Interações Hospedeiro-Patógeno/imunologia , Humanos , Imunidade , Isoenzimas , Modelos Moleculares , Oxisteróis/química , Oxisteróis/metabolismo , Proteínas Recombinantes , Relação Estrutura-Atividade , Tuberculose/microbiologia
12.
J Am Med Inform Assoc ; 28(1): 71-79, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33150354

RESUMO

OBJECTIVE: Clinical research informatics tools are necessary to support comprehensive studies of infectious diseases. The National Institute of Allergy and Infectious Diseases (NIAID) developed the publicly accessible Tuberculosis Data Exploration Portal (TB DEPOT) to address the complex etiology of tuberculosis (TB). MATERIALS AND METHODS: TB DEPOT displays deidentified patient case data and facilitates analyses across a wide range of clinical, socioeconomic, genomic, and radiological factors. The solution is built using Amazon Web Services cloud-based infrastructure, .NET Core, Angular, Highcharts, R, PLINK, and other custom-developed services. Structured patient data, pathogen genomic variants, and medical images are integrated into the solution to allow seamless filtering across data domains. RESULTS: Researchers can use TB DEPOT to query TB patient cases, create and save patient cohorts, and execute comparative statistical analyses on demand. The tool supports user-driven data exploration and fulfills the National Institute of Health's Findable, Accessible, Interoperable, and Reusable (FAIR) principles. DISCUSSION: TB DEPOT is the first tool of its kind in the field of TB research to integrate multidimensional data from TB patient cases. Its scalable and flexible architectural design has accommodated growth in the data, organizations, types of data, feature requests, and usage. Use of client-side technologies over server-side technologies and prioritizing maintenance have been important lessons learned. Future directions are dynamically prioritized and key functionality is shared through an application programming interface. CONCLUSION: This paper describes the platform development methodology, resulting functionality, benefits, and technical considerations of a clinical research informatics application to support increased understanding of TB.


Assuntos
Internet , Aplicações da Informática Médica , Tuberculose , Biologia Computacional , Bases de Dados como Assunto , Genômica , Humanos , National Institute of Allergy and Infectious Diseases (U.S.) , Radiologia , Software , Tuberculose/diagnóstico , Tuberculose/tratamento farmacológico , Tuberculose/genética , Tuberculose/prevenção & controle , Estados Unidos
13.
Nucleic Acids Res ; 49(D1): D288-D297, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33151284

RESUMO

The Database of Antimicrobial Activity and Structure of Peptides (DBAASP) is an open-access, comprehensive database containing information on amino acid sequences, chemical modifications, 3D structures, bioactivities and toxicities of peptides that possess antimicrobial properties. DBAASP is updated continuously, and at present, version 3.0 (DBAASP v3) contains >15 700 entries (8000 more than the previous version), including >14 500 monomers and nearly 400 homo- and hetero-multimers. Of the monomeric antimicrobial peptides (AMPs), >12 000 are synthetic, about 2700 are ribosomally synthesized, and about 170 are non-ribosomally synthesized. Approximately 3/4 of the entries were added after the initial release of the database in 2014 reflecting the recent sharp increase in interest in AMPs. Despite the increased interest, adoption of peptide antimicrobials in clinical practice is still limited as a consequence of several factors including side effects, problems with bioavailability and high production costs. To assist in developing and optimizing de novo peptides with desired biological activities, DBAASP offers several tools including a sophisticated multifactor analysis of relevant physicochemical properties. Furthermore, DBAASP has implemented a structure modelling pipeline that automates the setup, execution and upload of molecular dynamics (MD) simulations of database peptides. At present, >3200 peptides have been populated with MD trajectories and related analyses that are both viewable within the web browser and available for download. More than 400 DBAASP entries also have links to experimentally determined structures in the Protein Data Bank. DBAASP v3 is freely accessible at http://dbaasp.org.


Assuntos
Anti-Infecciosos/química , Peptídeos Catiônicos Antimicrobianos/química , Citotoxinas/química , Bases de Dados de Proteínas , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Citotoxinas/farmacologia , Humanos , Simulação de Dinâmica Molecular , Anotação de Sequência Molecular , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta
14.
PLoS One ; 15(1): e0224445, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978149

RESUMO

Availability of trained radiologists for fast processing of CXRs in regions burdened with tuberculosis always has been a challenge, affecting both timely diagnosis and patient monitoring. The paucity of annotated images of lungs of TB patients hampers attempts to apply data-oriented algorithms for research and clinical practices. The TB Portals Program database (TBPP, https://TBPortals.niaid.nih.gov) is a global collaboration curating a large collection of the most dangerous, hard-to-cure drug-resistant tuberculosis (DR-TB) patient cases. TBPP, with 1,179 (83%) DR-TB patient cases, is a unique collection that is well positioned as a testing ground for deep learning classifiers. As of January 2019, the TBPP database contains 1,538 CXRs, of which 346 (22.5%) are annotated by a radiologist and 104 (6.7%) by a pulmonologist-leaving 1,088 (70.7%) CXRs without annotations. The Qure.ai qXR artificial intelligence automated CXR interpretation tool, was blind-tested on the 346 radiologist-annotated CXRs from the TBPP database. Qure.ai qXR CXR predictions for cavity, nodule, pleural effusion, hilar lymphadenopathy was successfully matching human expert annotations. In addition, we tested the 12 Qure.ai classifiers to find whether they correlate with treatment success (information provided by treating physicians). Ten descriptors were found as significant: abnormal CXR (p = 0.0005), pleural effusion (p = 0.048), nodule (p = 0.0004), hilar lymphadenopathy (p = 0.0038), cavity (p = 0.0002), opacity (p = 0.0006), atelectasis (p = 0.0074), consolidation (p = 0.0004), indicator of TB disease (p = < .0001), and fibrosis (p = < .0001). We conclude that applying fully automated Qure.ai CXR analysis tool is useful for fast, accurate, uniform, large-scale CXR annotation assistance, as it performed well even for DR-TB cases that were not used for initial training. Testing artificial intelligence algorithms (encapsulating both machine learning and deep learning classifiers) on diverse data collections, such as TBPP, is critically important toward progressing to clinically adopted automatic assistants for medical data analysis.


Assuntos
Tuberculose Extensivamente Resistente a Medicamentos/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Derrame Pleural/diagnóstico por imagem , Tuberculose/diagnóstico por imagem , Algoritmos , Inteligência Artificial , Gerenciamento de Dados , Bases de Dados Factuais , Aprendizado Profundo , Tuberculose Extensivamente Resistente a Medicamentos/diagnóstico , Tuberculose Extensivamente Resistente a Medicamentos/fisiopatologia , Feminino , Humanos , Pulmão/fisiopatologia , Masculino , Derrame Pleural/diagnóstico , Derrame Pleural/fisiopatologia , Radiografia Torácica/métodos , Radiologistas , Tuberculose/diagnóstico , Tuberculose/fisiopatologia
15.
BMC Infect Dis ; 20(1): 17, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31910804

RESUMO

BACKGROUND: Recurrence of drug-resistant tuberculosis (DR-TB) after treatment occurs through relapse of the initial infection or reinfection by a new drug-resistant strain. Outbreaks of DR-TB in high burden regions present unique challenges in determining recurrence status for effective disease management and treatment. In the Republic of Moldova the burden of DR-TB is exceptionally high, with many cases presenting as recurrent. METHODS: We performed a retrospective analysis of Mycobacterium tuberculosis from Moldova to better understand the genomic basis of drug resistance and its effect on the determination of recurrence status in a high DR-burden environment. To do this we analyzed genomes from 278 isolates collected from 189 patients, including 87 patients with longitudinal samples. These pathogen genomes were sequenced using Illumina technology, and SNP panels were generated for each sample for use in phylogenetic and network analysis. Discordance between genomic resistance profiles and clinical drug-resistance test results was examined in detail to assess the possibility of mixed infection. RESULTS: There were clusters of multiple patients with 10 or fewer differences among DR-TB samples, which is evidence of person-to-person transmission of DR-TB. Analysis of longitudinally collected isolates revealed that many infections exhibited little change over time, though 35 patients demonstrated reinfection by divergent (number of differences > 10) lineages. Additionally, several same-lineage sample pairs were found to be more divergent than expected for a relapsed infection. Network analysis of the H3/4.2.1 clade found very close relationships among 61 of these samples, making differentiation of reactivation and reinfection difficult. There was discordance between genomic profile and clinical drug sensitivity test results in twelve samples, and four of these had low level (but not statistically significant) variation at DR SNPs suggesting low-level mixed infections. CONCLUSIONS: Whole-genome sequencing provided a detailed view of the genealogical structure of the DR-TB epidemic in Moldova, showing that reinfection may be more prevalent than currently recognized. We also found increased evidence of mixed infection, which could be more robustly characterized with deeper levels of genomic sequencing.


Assuntos
Antituberculosos/uso terapêutico , Farmacorresistência Bacteriana Múltipla/genética , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia , Sequenciamento Completo do Genoma/métodos , Adolescente , Adulto , Idoso , Antituberculosos/efeitos adversos , Feminino , Humanos , Incidência , Estudos Longitudinais , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Moldávia , Mycobacterium tuberculosis/isolamento & purificação , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Recidiva , Estudos Retrospectivos , Adulto Jovem
16.
Infect Genet Evol ; 78: 104137, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31838261

RESUMO

Mycobacterium tuberculosis (M.tb) is the leading cause of death from an infectious disease. Drug resistant tuberculosis (DR-TB) threatens to exacerbate challenges in diagnostics and treatment. It is important to monitor strains circulating in countries with heavy burden of DR-TB, to make informed decisions about treatment, and because in these countries there is an elevated probability that DR-TB may advance to the totally drug resistant form. The TB Portals Program (TBPP, https://TBPortals.niaid.nih.gov) formed a global network of participating institutions and hospitals collecting and analyzing de-identified clinical, imaging and socioeconomic data, augmenting these with genomic sequencing results. TB Portals database includes complete M.tb genomes, with the information about spoligotypes, strains, and genomic variants related to drug resistance. Within the framework of TB Portals, we created Data Exploration Portal (DEPOT), to facilitate visualization and statistical analysis of user-defined cohorts from the entire TB Portals database. A continuing TB Portals research objective is to actively monitor and examine genomic variability that may account for observed differences in DR-TB incident rates and/or difficulties with diagnosis and treatment. Our analysis identified that several genomic variants implicated in drug resistance or improved fitness of the pathogen, were significantly more frequent in M.tb strains circulating in Belarus in comparison with other countries. Further studies are necessary to reveal whether the corresponding genomic variants may explain unusually high burden of drug-resistant M.tb in Belarus and suggest improvements for diagnostic and drug therapies.


Assuntos
Mycobacterium tuberculosis/genética , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Azerbaijão/epidemiologia , Bases de Dados Factuais , Variação Genética , Genoma Bacteriano , Genômica , República da Geórgia/epidemiologia , Humanos , Moldávia/epidemiologia , Mycobacterium tuberculosis/isolamento & purificação , Polimorfismo de Nucleotídeo Único , República de Belarus/epidemiologia , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia
17.
Quant Imaging Med Surg ; 9(6): 1132-1146, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31367568

RESUMO

Tuberculosis (TB) is currently the world's leading cause of infectious mortality. The complex immune response of the human body to Mycobacterium tuberculosis (M.tb) results in a wide array of clinical manifestations, thus the clinical and radiological diagnosis can be challenging. 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) scan with/without computed tomography (CT) component images the whole body and provides a metabolic map of the infection, enabling clinicians to assess the disease burden. 18F-FDG-PET/CT scan is particularly useful in detecting the disease in previously unknown sites, and allows the most appropriate site of biopsy to be selected. 18F-FDG-PET/CT is also very valuable in assessing early disease response to therapy, and plays an important role in cases where conventional microbiological methods are unavailable and for monitoring response to therapy in cases of multidrug-resistant TB or extrapulmonary TB. 18F-FDG-PET/CT cannot reliably differentiate active TB lesion from malignant lesions and false positives can also be due to other infective or inflammatory conditions. 18F-FDG PET is also unable to distinguish tuberculous lymphadenitis from metastatic lymph node involvement. The lack of specificity is a limitation for 18F-FDG-PET/CT in TB management.

18.
Pharmaceuticals (Basel) ; 12(2)2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31163671

RESUMO

Antimicrobial peptides (AMPs) have been identified as a potentially new class of antibiotics to combat bacterial resistance to conventional drugs. The design of de novo AMPs with high therapeutic indexes, low cost of synthesis, high resistance to proteases and high bioavailability remains a challenge. Such design requires computational modeling of antimicrobial properties. Currently, most computational methods cannot accurately calculate antimicrobial potency against particular strains of bacterial pathogens. We developed a tool for AMP prediction (Special Prediction (SP) tool) and made it available on our Web site (https://dbaasp.org/prediction). Based on this tool, a simple algorithm for the design of de novo AMPs (DSP) was created. We used DSP to design short peptides with high therapeutic indexes against gram-negative bacteria. The predicted peptides have been synthesized and tested in vitro against a panel of gram-negative bacteria, including drug resistant ones. Predicted activity against Escherichia coli ATCC 25922 was experimentally confirmed for 14 out of 15 peptides. Further improvements for designed peptides included the synthesis of D-enantiomers, which are traditionally used to increase resistance against proteases. One synthetic D-peptide (SP15D) possesses one of the lowest values of minimum inhibitory concentration (MIC) among all DBAASP database short peptides at the time of the submission of this article, while being highly stable against proteases and having a high therapeutic index. The mode of anti-bacterial action, assessed by fluorescence microscopy, shows that SP15D acts similarly to cell penetrating peptides. SP15D can be considered a promising candidate for the development of peptide antibiotics. We plan further exploratory studies with the SP tool, aiming at finding peptides which are active against other pathogenic organisms.

19.
PLoS One ; 14(5): e0217410, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31120982

RESUMO

The NIAID TB Portals Program (TBPP) established a unique and growing database repository of socioeconomic, geographic, clinical, laboratory, radiological, and genomic data from patient cases of drug-resistant tuberculosis (DR-TB). Currently, there are 2,428 total cases from nine country sites (Azerbaijan, Belarus, Moldova, Georgia, Romania, China, India, Kazakhstan, and South Africa), 1,611 (66%) of which are multidrug- or extensively-drug resistant and 1,185 (49%), 863 (36%), and 952 (39%) of which contain X-ray, computed tomography (CT) scan, and genomic data, respectively. We introduce the Data Exploration Portal (TB DEPOT, https://depot.tbportals.niaid.nih.gov) to visualize and analyze these multi-domain data. The TB DEPOT leverages the TBPP integration of clinical, socioeconomic, genomic, and imaging data into standardized formats and enables user-driven, repeatable, and reproducible analyses. It furthers the TBPP goals to provide a web-enabled analytics platform to countries with a high burden of multidrug-resistant TB (MDR-TB) but limited IT resources and inaccessible data, and enables the reusability of data, in conformity with the NIH's Findable, Accessible, Interoperable, and Reusable (FAIR) principles. TB DEPOT provides access to "analysis-ready" data and the ability to generate and test complex clinically-oriented hypotheses instantaneously with minimal statistical background and data processing skills. TB DEPOT is also promising for enhancing medical training and furnishing well annotated, hard to find, MDR-TB patient cases. TB DEPOT, as part of TBPP, further fosters collaborative research efforts to better understand drug-resistant tuberculosis and aid in the development of novel diagnostics and personalized treatment regimens.


Assuntos
Bases de Dados Factuais , Tuberculose Resistente a Múltiplos Medicamentos , Big Data , Estudos de Coortes , Análise de Dados , Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano , Humanos , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , National Institute of Allergy and Infectious Diseases (U.S.) , Polimorfismo de Nucleotídeo Único , Tuberculose Resistente a Múltiplos Medicamentos/diagnóstico por imagem , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Estados Unidos , Navegador
20.
IEEE/ACM Trans Comput Biol Bioinform ; 16(4): 1398-1408, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-28678713

RESUMO

Emergence of drug-resistant microorganisms has been recognized as a serious threat to public health worldwide. This problem is extensively discussed in the context of tuberculosis treatment. Alterations in pathogen genomes are among the main mechanisms by which microorganisms exhibit drug resistance. Analysis of 144 M. tuberculosis strains of different phenotypes including drug susceptible, MDR, and XDR isolated in Belarus was fulfilled in this paper. A wide range of machine learning methods that can discover SNPs related to drug-resistance in the whole bacteria genomes was investigated. Besides single-SNP testing approaches, methods that allow detecting joint effects from interacting SNPs were considered. We proposed a framework for automated selection of the best performing statistical model in terms of recall, precision, and accuracy to identify drug resistance-associated mutations. Analysis of whole-genome sequences often leads to situations where the number of treated features exceeds the number of available observations. For this reason, special attention is paid to fair evaluation of the model prediction quality and minimizing the risk of overfitting while estimating the underlying parameters. Results of our experiments aimed at identifying top-scoring resistance mutations to the major first-line and second-line anti-TB drugs are presented.


Assuntos
Tuberculose Extensivamente Resistente a Medicamentos/microbiologia , Estudo de Associação Genômica Ampla , Mycobacterium tuberculosis/genética , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Algoritmos , Alelos , Antituberculosos/farmacologia , Teorema de Bayes , Farmacorresistência Bacteriana , Tuberculose Extensivamente Resistente a Medicamentos/epidemiologia , Variação Genética , Genoma , Humanos , Aprendizado de Máquina , Modelos Estatísticos , Mutação , Fenótipo , Filogenia , Análise de Componente Principal , República de Belarus/epidemiologia , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...