45 results on '"Refrégier G"'
Search Results
2. Genomic characterization of MDR/XDR-TB in Kazakhstan by a combination of high-throughput methods predominantly shows the ongoing transmission of L2/Beijing 94–32 central Asian/Russian clusters
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Klotoe, B. J., Kacimi, S., Costa-Conceicão, E., Gomes, H. M., Barcellos, R. B., Panaiotov, S., Haj Slimene, D., Sikhayeva, N., Sengstake, S., Schuitema, A. R., Akhalaia, M., Alenova, A., Zholdybayeva, E., Tarlykov, P., Anthony, R., Refrégier, G., and Sola, C.
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- 2019
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3. Hybrid sterility and inviability in the parasitic fungal species complex Microbotryum
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DE VIENNE, D. M., REFRÉGIER, G., HOOD, M. E., GUIGUE, A., DEVIER, B., VERCKEN, E., SMADJA, C., DESEILLE, A., and GIRAUD, T.
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- 2009
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4. Genomics and Machine Learning for Taxonomy Consensus: The Mycobacterium tuberculosis Complex Paradigm.
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Azé, J., Sola, C., Zhang, J., Lafosse-Marin, F., Yasmin, M., Siddiqui, R., Kremer, K., Soolingen, D. van, Refrégier, G., Azé, J., Sola, C., Zhang, J., Lafosse-Marin, F., Yasmin, M., Siddiqui, R., Kremer, K., Soolingen, D. van, and Refrégier, G.
- Abstract
Contains fulltext : 155365.PDF (publisher's version ) (Open Access)
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- 2015
5. An “all-in-one” solution for simultaneous spoligotyping and drug resistance gene analysis of Mycobacterium tuberculosis: TB-SPRINT and TB-SPRINTplus
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Gomgnimbou, M.K., primary, Klotoe, B.J., additional, Molina, B., additional, Dominguez, J., additional, Refrégier, G., additional, and Sola, C., additional
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- 2015
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6. Cospeciation vs host‐shift speciation: methods for testing, evidence from natural associations and relation to coevolution
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de Vienne, D. M., primary, Refrégier, G., additional, López‐Villavicencio, M., additional, Tellier, A., additional, Hood, M. E., additional, and Giraud, T., additional
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- 2013
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7. Cospeciation vs host-shift speciation: methods for testing, evidence from natural associations and relation to coevolution.
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Vienne, D. M., Refrégier, G., López‐Villavicencio, M., Tellier, A., Hood, M. E., and Giraud, T.
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ADAPTIVE radiation , *HOSTS (Biology) , *HOST-parasite relationships , *HOST plants , *SYMBIOSIS , *PARASITES , *COEVOLUTION , *PHYLOGENY - Abstract
347I.348II.349III.349IV.355V.378VI.381381References381Glossary379 Summary: Hosts and their symbionts are involved in intimate physiological and ecological interactions. The impact of these interactions on the evolution of each partner depends on the time‐scale considered. Short‐term dynamics – ‘coevolution’ in the narrow sense – has been reviewed elsewhere. We focus here on the long‐term evolutionary dynamics of cospeciation and speciation following host shifts. Whether hosts and their symbionts speciate in parallel, by cospeciation, or through host shifts, is a key issue in host–symbiont evolution. In this review, we first outline approaches to compare divergence between pairwise associated groups of species, their advantages and pitfalls. We then consider recent insights into the long‐term evolution of host–parasite and host–mutualist associations by critically reviewing the literature. We show that convincing cases of cospeciation are rare (7%) and that cophylogenetic methods overestimate the occurrence of such events. Finally, we examine the relationships between short‐term coevolutionary dynamics and long‐term patterns of diversification in host–symbiont associations. We review theoretical and experimental studies showing that short‐term dynamics can foster parasite specialization, but that these events can occur following host shifts and do not necessarily involve cospeciation. Overall, there is now substantial evidence to suggest that coevolutionary dynamics of hosts and parasites do not favor long‐term cospeciation. [ABSTRACT FROM AUTHOR]
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- 2013
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8. Spoligotyping of Mycobacterium africanum, Burkina Faso.
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Gomgnimbou MK, Refrégier G, Diagbouga SP, Adama S, Kaboré A, Ouiminga A, Sola C, Gomgnimbou, Michel K, Refrégier, Guislaine, Diagbouga, Serge P, Adama, Sanou, Kaboré, Antoinette, Ouiminga, Adama, and Sola, Christophe
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Using Ziehl-Neelsen-positive slides collected from tuberculosis diagnostic centers in Burkina Faso, we showed that 20% of 80 spoligotyping-positive DNA samples had a characteristic Mycobacterium africanum-specific genomic signature. This result suggests that M. africanum is still present in Burkina Faso at almost the same prevalence as 15-20 years ago. [ABSTRACT FROM AUTHOR]
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- 2012
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9. Using affinity propagation for identifying subspecies among clonal organisms: lessons from M. tuberculosis
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Franz Silvio, Labarre Mathieu, Borile Claudio, Sola Christophe, and Refrégier Guislaine
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asexual organisms ,species delineation ,epidemiology ,DR locus ,Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Biology (General) ,QH301-705.5 - Abstract
Abstract Background Classification and naming is a key step in the analysis, understanding and adequate management of living organisms. However, where to set limits between groups can be puzzling especially in clonal organisms. Within the Mycobacterium tuberculosis complex (MTC), the etiological agent of tuberculosis (TB), experts have first identified several groups according to their pattern at repetitive sequences, especially at the CRISPR locus (spoligotyping), and to their epidemiological relevance. Most groups such as "Beijing" found good support when tested with other loci. However, other groups such as T family and T1 subfamily (belonging to the "Euro-American" lineage) correspond to non-monophyletic groups and still need to be refined. Here, we propose to use a method called Affinity Propagation that has been successfully used in image categorization to identify relevant patterns at the CRISPR locus in MTC. Results To adequately infer the relative divergence time between strains, we used a distance method inspired by the recent evolutionary model by Reyes et al. We first confirm that this method performs better than the Jaccard index commonly used to compare spoligotype patterns. Second, we document the support of each spoligotype family among the previous classification using affinity propagation on the international spoligotyping database SpolDB4. This allowed us to propose a consensus assignation for all SpolDB4 spoligotypes. Third, we propose new signatures to subclassify the T family. Conclusion Altogether, this study shows how the new clustering algorithm Affinity Propagation can help building or refining clonal organims classifications. It also describes well-supported families and subfamilies among M. tuberculosis complex, especially inside the modern "Euro-American" lineage.
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- 2011
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10. The use of microbead-based spoligotyping for Mycobacterium tuberculosis complex to evaluate the quality of the conventional method: Providing guidelines for Quality Assurance when working on membranes
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Garzelli Carlo, Rastogi Nalin, Al-Hajoj Sahal, Herranz Marta, de Viedma Darío, Rasolofo-Razanamparany Voahangy, Stoffels Karolien, Fauville-Dufaux Maryse, Elias Atiná, Gomes Harrison, Rigouts Leen, Ruimy Raymond, Kremer Kristin, Ritacco Viviana, Zhang Jian, Abadia Edgar, Tortoli Enrico, Suffys Philip N, van Soolingen Dick, Refrégier Guislaine, and Sola Christophe
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Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background The classical spoligotyping technique, relying on membrane reverse line-blot hybridization of the spacers of the Mycobacterium tuberculosis CRISPR locus, is used world-wide (598 references in Pubmed on April 8th, 2011). However, until now no inter-laboratory quality control study had been undertaken to validate this technique. We analyzed the quality of membrane-based spoligotyping by comparing it to the recently introduced and highly robust microbead-based spoligotyping. Nine hundred and twenty-seven isolates were analyzed totaling 39,861 data points. Samples were received from 11 international laboratories with a worldwide distribution. Methods The high-throughput microbead-based Spoligotyping was performed on CTAB and thermolyzate DNA extracted from isolated Mycobacterium tuberculosis complex (MTC) strains coming from the genotyping participating centers. Information regarding how the classical Spoligotyping method was performed by center was available. Genotype discriminatory analyses were carried out by comparing the spoligotypes obtained by both methods. The non parametric U-Mann Whitney homogeneity test and the Spearman rank correlation test were performed to validate the observed results. Results Seven out of the 11 laboratories (63 %), perfectly typed more than 90% of isolates, 3 scored between 80-90% and a single center was under 80% reaching 51% concordance only. However, this was mainly due to discordance in a single spacer, likely having a non-functional probe on the membrane used. The centers using thermolyzate DNA performed as well as centers using the more extended CTAB extraction procedure. Few centers shared the same problematic spacers and these problematic spacers were scattered over the whole CRISPR locus (Mostly spacers 15, 14, 18, 37, 39, 40). Conclusions We confirm that classical spoligotyping is a robust method with generally a high reliability in most centers. The applied DNA extraction procedure (CTAB or thermolyzate) did not affect the results in this study. However performance was center-dependent, suggesting that training is a key component in quality assurance of spoligotyping. Overall, no particular spacer yielded a higher degree of deviating results, suggesting that errors occur randomly either in the process of re-using membranes, or during the reading of the results and transferring of data from the film to a digital file. Last, the performance of the microbead-based method was excellent as previously shown by Cowan et al. (J. Clin. Microbiol. 2004) and Zhang et al. (J. Med. Microbiol. 2009) and demonstrated the proper detection of spacer 15 that is known to occasionally give weak signals in the classical spoligotyping.
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- 2011
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11. A first assessment of the genetic diversity of Mycobacterium tuberculosis complex in Cambodia
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Sola Christophe, Gicquel Brigitte, Refregier Guislaine, Heng Seiha, Le Moullec Stéphanie, Zhang Jian, and Guillard Bertrand
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Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Cambodia is among the 22 high-burden TB countries, and has one of the highest rates of TB in South-East Asia. This study aimed to describe the genetic diversity among clinical Mycobacterium tuberculosis complex (MTC) isolates collected in Cambodia and to relate these findings to genetic diversity data from neighboring countries. Methods We characterized by 24 VNTR loci genotyping and spoligotyping 105 Mycobacterium tuberculosis clinical isolates collected between 2007 and 2008 in the region of Phnom-Penh, Cambodia, enriched in multidrug-resistant (MDR) isolates (n = 33). Results Classical spoligotyping confirmed that the East-African Indian (EAI) lineage is highly prevalent in this area (60%-68% respectively in whole sample and among non-MDR isolates). Beijing lineage is also largely represented (30% in whole sample, 21% among non-MDR isolates, OR = 4.51, CI95% [1.77, 11.51]) whereas CAS lineage was absent. The 24 loci MIRU-VNTR typing scheme distinguished 90 patterns with only 13 multi-isolates clusters covering 28 isolates. The clustering of EAI strains could be achieved with only 8 VNTR combined with spoligotyping, which could serve as a performing, easy and cheap genotyping standard for this family. Extended spoligotyping suggested relatedness of some unclassified "T1 ancestors" or "Manu" isolates with modern strains and provided finer resolution. Conclusions The genetic diversity of MTC in Cambodia is driven by the EAI and the Beijing families. We validate the usefulness of the extended spoligotyping format in combination with 8 VNTR for EAI isolates in this region.
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- 2011
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12. Cophylogeny of the anther smut fungi and their caryophyllaceous hosts: Prevalence of host shifts and importance of delimiting parasite species for inferring cospeciation
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Yockteng Roxana, Shykoff Jacqui A, Widmer Alex, Jabbour Florian, Le Gac Mickaël, Refrégier Guislaine, Hood Michael E, and Giraud Tatiana
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Evolution ,QH359-425 - Abstract
Abstract Background Using phylogenetic approaches, the expectation that parallel cladogenesis should occur between parasites and hosts has been validated in some studies, but most others provided evidence for frequent host shifts. Here we examine the evolutionary history of the association between Microbotryum fungi that cause anther smut disease and their Caryophyllaceous hosts. We investigated the congruence between host and parasite phylogenies, inferred cospeciation events and host shifts, and assessed whether geography or plant ecology could have facilitated the putative host shifts identified. For cophylogeny analyses on microorganisms, parasite strains isolated from different host species are generally considered to represent independent evolutionary lineages, often without checking whether some strains actually belong to the same generalist species. Such an approach may mistake intraspecific nodes for speciation events and thus bias the results of cophylogeny analyses if generalist species are found on closely related hosts. A second aim of this study was therefore to evaluate the impact of species delimitation on the inferences of cospeciation. Results We inferred a multiple gene phylogeny of anther smut strains from 21 host plants from several geographic origins, complementing a previous study on the delimitation of fungal species and their host specificities. We also inferred a multi-gene phylogeny of their host plants, and the two phylogenies were compared. A significant level of cospeciation was found when each host species was considered to harbour a specific parasite strain, i.e. when generalist parasite species were not recognized as such. This approach overestimated the frequency of cocladogenesis because individual parasite species capable of infecting multiple host species (i.e. generalists) were found on closely related hosts. When generalist parasite species were appropriately delimited and only a single representative of each species was retained, cospeciation events were not more frequent than expected under a random distribution, and many host shifts were inferred. Current geographic distributions of host species seemed to be of little relevance for understanding the putative historical host shifts, because most fungal species had overlapping geographic ranges. We did detect some ecological similarities, including shared pollinators and habitat types, between host species that were diseased by closely related anther smut species. Overall, genetic similarity underlying the host-parasite interactions appeared to have the most important influence on specialization and host-shifts: generalist multi-host parasite species were found on closely related plant species, and related species in the Microbotryum phylogeny were associated with members of the same host clade. Conclusion We showed here that Microbotryum species have evolved through frequent host shifts to moderately distant hosts, and we show further that accurate delimitation of parasite species is essential for interpreting cophylogeny studies.
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- 2008
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13. Molecular epidemiology of tuberculosis in Sicily, Italy: what has changed after a decade?
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Michel K. Gomgnimbou, Aurora Aleo, Teresa Fasciana, Guislaine Refrégier, Celestino Bonura, Anna Giammanco, Caterina Mammina, Christophe Sola, Bonura, C, Gomgnimbou, MK, Refrégier, G, Aleo, A, Fasciana, T, Giammanco, A, Sola, C, and Mammina C.
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Adult ,Male ,Settore MED/07 - Microbiologia E Microbiologia Clinica ,Veterinary medicine ,Tuberculosis, Sicily, Epidemiology, Spoligotyping, MIRU-VNTR ,Tuberculosis ,Genotype ,Epidemiology ,Lineage (evolution) ,Microbial Sensitivity Tests ,Minisatellite Repeats ,Settore MED/42 - Igiene Generale E Applicata ,MIRU-VNTR ,Drug Resistance, Bacterial ,Isoniazid ,Medicine ,Humans ,Typing ,Sicily ,Antibiotics, Antitubercular ,Ethambutol ,Spoligotyping ,Molecular Epidemiology ,Molecular epidemiology ,biology ,business.industry ,Mycobacterium tuberculosis ,Middle Aged ,medicine.disease ,biology.organism_classification ,Molecular Typing ,Infectious Diseases ,Parasitology ,Mycobacterium tuberculosis complex ,Streptomycin ,Female ,Rifampin ,business ,medicine.drug ,Research Article - Abstract
Background We aimed to investigate the molecular epidemiology of Mycobacterium tuberculosis complex (MTBC) isolates in the province of Palermo, Sicily, Italy, by characterizing 183 isolates identified in the years 2004-2012. A comparison with 104 MTBC strains identified in the same geographic area in the years 1994-2000 was also carried out. Methods One hundred eighty-three MTBC isolates identified in Palermo, Italy, in the years 2004-2012 were analyzed by spoligotyping and the 24 mycobacterial interspersed repetitive unit (MIRU)-variable-number tandem-repeat (VNTR) method typing. Susceptibility testing to streptomycin, isoniazid, rifampin and ethambutol was also performed. Furthermore, the spoligotyping dataset obtained from 104 MTBC isolates identified from 1994 to 2000 was reanalyzed. Distribution into lineages and clustering of isolates in the two periods was compared. Results One hundred seventy-seven out of the 183 isolates of MTBC submitted to molecular typing were fully characterized. Of these, 108 were from Italian-born and 69 from foreign-born individuals. Eleven different lineages and 35 families-subfamilies were identified with the most represented lineages being Haarlem (26.5%), T (19.2%), LAM (13.6%) and S (8.5%). Except for the Haarlem lineage, where isolates from foreign-born patients were overrepresented, the distribution of isolates in the families belonging to the Euro-American clone reflected the proportions of the two subpopulations. A total of 27 (15.2%) strains were clustered and three clusters were mixed. Approximately 25% of the 183 MTBC isolates under study proved to be resistant to at least one antiTB drug, with only three isolates categorized as multidrug resistant (MDR). When MTBC isolates identified in the years 1994-2000 were reanalyzed, lineages T (30.8%), LAM (29.8%), Haarlem (16.3%) and S (13.5%) proved to be predominant. No MTBC isolates belonging to CAM, U, CAS, Turkish and Ural lineages were identified. Conclusions A wide heterogeneity was detected among the MTBC strains isolated in the years 2004-2012. Six lineages were not present among the isolates of the period 1994-2000. Comparison between distribution of lineages in the two consecutive periods depicts rapid and deep changes in the TB epidemiology in Palermo, Italy. An universal and continued laboratory-based surveillance of TB in Sicily is required. Electronic supplementary material The online version of this article (doi:10.1186/s12879-014-0602-4) contains supplementary material, which is available to authorized users.
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- 2014
14. Newly Identified Mycobacterium africanum Lineage 10, Central Africa.
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Guyeux C, Senelle G, Le Meur A, Supply P, Gaudin C, Phelan JE, Clark TG, Rigouts L, de Jong B, Sola C, and Refrégier G
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- Phylogeny, Software, Africa, Central epidemiology, Biological Evolution, Mycobacterium genetics
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Analysis of genome sequencing data from >100,000 genomes of Mycobacterium tuberculosis complex using TB-Annotator software revealed a previously unknown lineage, proposed name L10, in central Africa. Phylogenetic reconstruction suggests L10 could represent a missing link in the evolutionary and geographic migration histories of M. africanum.
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- 2024
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15. Towards the reconstruction of a global TB history using a new pipeline "TB-Annotator".
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Senelle G, Sahal MR, La K, Billard-Pomares T, Marin J, Mougari F, Bridier-Nahmias A, Carbonnelle E, Cambau E, Refrégier G, Guyeux C, and Sola C
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- Humans, Animals, Phylogeny, Genome-Wide Association Study, Computational Biology, Mycobacterium tuberculosis genetics, Tuberculosis diagnosis, Tuberculosis genetics, Tuberculosis epidemiology
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Mycobacterium tuberculosis complex (MTBC) has a population structure consisting of 9 human and animal lineages. The genomic diversity within these lineages is a pathogenesis factor that affects virulence, transmissibility, host response, and antibiotic resistance. Hence it is important to develop improved information systems for tracking and understanding the spreading and evolution of genomes. We present results obtained thanks to a new informatics platform for computational biology of MTBC, that uses a convenience sample from public/private SRAs, designated as TB-Annotator. Version 1 was a first interactive graphic-based web tool based on 15,901 representative genomes. Version 2, still interactive, is a more sophisticated database, developed using the Snakemake Workflow Management System (WMS) that allows an unsupervised global and scalable analysis of the content of the USA National Center for Biotechnology Information Short Read Archives database. This platform analyzes nucleotide variants, the presence/absence of genes, known regions of difference and detect new deletions, the insertion sites of mobile genetic elements, and allows phylogenetic trees to be built, imported in a graphical interface and interactively analyzed between the data and the tree. The objective of TB-Annotator is triple: detect recent epidemiological links, reconstruct distant phylogeographical histories as well as perform more complex phenotypic/genotypic Genome-Wide Association Studies (GWAS). In this paper, we compare the various taxonomic SNPs-based labels and hierarchies previously described in recent reference papers for L1, and present a comparative analysis that allows identification of alias and thus provides the basis of a future unifying naming scheme for L1 sublineages. We present a global phylogenetic tree built with RAxML-NG, and one on L2; at the time of writing, we characterized about 200 sublineages, with many new ones; a detail tree for Modern L2 and a hierarchical scheme allowing to facilitate L2 lineage assignment are also presented., Competing Interests: Declaration of competing interest None declared., (Copyright © 2023. Published by Elsevier Ltd.)
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- 2023
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16. Towards a better understanding of the long-lasting evolutionary history of Mycobacterium tuberculosis.
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Senelle G, Guyeux C, Refrégier G, and Sola C
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- Humans, Animals, Phylogeny, Polymorphism, Single Nucleotide, Genotype, Mycobacterium tuberculosis genetics, Tuberculosis diagnosis, Tuberculosis genetics, Tuberculosis microbiology
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The daily increasing sequencing of Mycobacterium tuberculosis has made it possible to establish an advanced phylogeny of this bacterium. It currently includes 9 lineages mainly affecting humans, completed by animal lineages, which form the Mycobacterium tuberculosis complex. Inherited from various historical approaches, this phylogeny is now based on Single Nucleotide Polymorphisms (SNPs), of which updates are frequently proposed. We present here evidence that the task needs refinements: some lineages have currently suboptimal defining SNPs, and many sublineages still need to be named and characterized. These findings are based on a new tool specifically designed to index the entire existing sequencing data. In this article, we focus on lineages 4.5, 4.7, 6 and 7. We take the opportunity to present some evidence that TB-annotator shows strong relevance, identifying well supported sublineages, as well as good global agreement with previous findings., Competing Interests: Declaration of competing interest None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
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- 2023
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17. Comparison of in silico predicted Mycobacterium tuberculosis spoligotypes and lineages from whole genome sequencing data.
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Napier G, Couvin D, Refrégier G, Guyeux C, Meehan CJ, Sola C, Campino S, Phelan J, and Clark TG
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- Humans, Bacterial Typing Techniques, Drug Resistance, Beijing, Genotype, Mycobacterium tuberculosis, Tuberculosis microbiology
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Bacterial strain-types in the Mycobacterium tuberculosis complex underlie tuberculosis disease, and have been associated with drug resistance, transmissibility, virulence, and host-pathogen interactions. Spoligotyping was developed as a molecular genotyping technique used to determine strain-types, though recent advances in whole genome sequencing (WGS) technology have led to their characterization using SNP-based sub-lineage nomenclature. Notwithstanding, spoligotyping remains an important tool and there is a need to study the congruence between spoligotyping-based and SNP-based sub-lineage assignation. To achieve this, an in silico spoligotype prediction method ("Spolpred2") was developed and integrated into TB-Profiler. Lineage and spoligotype predictions were generated for > 28 k isolates and the overlap between strain-types was characterized. Major spoligotype families detected were Beijing (25.6%), T (18.6%), LAM (13.1%), CAS (9.4%), and EAI (8.3%), and these broadly followed known geographic distributions. Most spoligotypes were perfectly correlated with the main MTBC lineages (L1-L7, plus animal). Conversely, at lower levels of the sub-lineage system, the relationship breaks down, with only 65% of spoligotypes being perfectly associated with a sub-lineage at the second or subsequent levels of the hierarchy. Our work supports the use of spoligotyping (membrane or WGS-based) for low-resolution surveillance, and WGS or SNP-based systems for higher-resolution studies., (© 2023. The Author(s).)
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- 2023
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18. The future of CRISPR in Mycobacterium tuberculosis infection.
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Zein-Eddine R, Refrégier G, Cervantes J, and Yokobori NK
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- Humans, CRISPR-Cas Systems, Phylogeny, Genes, Bacterial, Tuberculosis diagnosis, Tuberculosis genetics, Mycobacterium tuberculosis genetics
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Clustered Regularly Interspaced Short Palindromic repeats (CRISPR)-Cas systems rapidly raised from a bacterial genetic curiosity to the most popular tool for genetic modifications which revolutionized the study of microbial physiology. Due to the highly conserved nature of the CRISPR locus in Mycobacterium tuberculosis, the etiological agent of one of the deadliest infectious diseases globally, initially, little attention was paid to its CRISPR locus, other than as a phylogenetic marker. Recent research shows that M. tuberculosis has a partially functional Type III CRISPR, which provides a defense mechanism against foreign genetic elements mediated by the ancillary RNAse Csm6. With the advent of CRISPR-Cas based gene edition technologies, our possibilities to explore the biology of M. tuberculosis and its interaction with the host immune system are boosted. CRISPR-based diagnostic methods can lower the detection threshold to femtomolar levels, which could contribute to the diagnosis of the still elusive paucibacillary and extrapulmonary tuberculosis cases. In addition, one-pot and point-of-care tests are under development, and future challenges are discussed. We present in this literature review the potential and actual impact of CRISPR-Cas research on human tuberculosis understanding and management. Altogether, the CRISPR-revolution will revitalize the fight against tuberculosis with more research and technological developments., (© 2023. The Author(s).)
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- 2023
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19. Investigating the Diversity of Tuberculosis Spoligotypes with Dimensionality Reduction and Graph Theory.
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Senelle G, Guyeux C, Refrégier G, and Sola C
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- Animals, Tuberculosis genetics, Tuberculosis microbiology, Mycobacterium tuberculosis genetics
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The spoligotype is a graphical description of the CRISPR locus present in Mycobacterium tuberculosis , which has the particularity of having only 68 possible spacers. This spoligotype, which can be easily obtained either in vitro or in silico, allows to have a summary information of lineage or even antibiotic resistance (when known to be associated to a particular cluster) at a lower cost. The objective of this article is to show that this representation is richer than it seems, and that it is under-exploited until now. We first recall an original way to represent these spoligotypes as points in the plane, allowing to highlight possible sub-lineages, particularities in the animal strains, etc. This graphical representation shows clusters and a skeleton in the form of a graph, which led us to see these spoligotypes as vertices of an unconnected directed graph. In this paper, we therefore propose to exploit in detail the description of the variety of spoligotypes using a graph, and we show to what extent such a description can be informative.
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- 2022
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20. Mycobacterium tuberculosis genetic features associated with pulmonary tuberculosis severity.
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Genestet C, Refrégier G, Hodille E, Zein-Eddine R, Le Meur A, Hak F, Barbry A, Westeel E, Berland JL, Engelmann A, Verdier I, Lina G, Ader F, Dray S, Jacob L, Massol F, Venner S, and Dumitrescu O
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- Humans, Genome-Wide Association Study, Whole Genome Sequencing, Antitubercular Agents therapeutic use, Mycobacterium tuberculosis genetics, Tuberculosis, Pulmonary diagnosis, Tuberculosis, Pulmonary drug therapy, Tuberculosis drug therapy, Tuberculosis, Multidrug-Resistant drug therapy
- Abstract
Objectives: Mycobacterium tuberculosis (Mtb) infections result in a wide spectrum of clinical presentations but without proven Mtb genetic determinants. Herein, we hypothesized that the genetic features of Mtb clinical isolates, such as specific polymorphisms or microdiversity, may be linked to tuberculosis (TB) severity., Methods: A total of 234 patients with pulmonary TB (including 193 drug-susceptible and 14 monoresistant cases diagnosed between 2017 and 2020 and 27 multidrug-resistant cases diagnosed between 2010 and 2020) were stratified according to TB disease severity, and Mtb genetic features were explored using whole genome sequencing, including heterologous single-nucleotide polymorphism (SNP), calling to explore microdiversity. Finally, we performed a structural equation modeling analysis to relate TB severity to Mtb genetic features., Results: The clinical isolates from patients with mild TB carried mutations in genes associated with host-pathogen interaction, whereas those from patients with moderate/severe TB carried mutations associated with regulatory mechanisms. Genome-wide association study identified an SNP in the promoter of the gene coding for the virulence regulator espR, statistically associated with moderate/severe disease. Structural equation modeling and model comparisons indicated that TB severity was associated with the detection of Mtb microdiversity within clinical isolates and to the espR SNP., Conclusion: Taken together, these results provide a new insight to better understand TB pathophysiology and could provide a new prognosis tool for pulmonary TB severity., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
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- 2022
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21. Mycobacterium tuberculosis Diversity Exploration: A Way to Serve the Three Main Weapons against Epidemics, Hygiene, Vaccine Development and Chemotherapy.
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Refrégier G and Genestet C
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As highlighted by the SARS pandemic which is still ongoing, the battle against pathogens relies on three main "weapons": hygiene, vaccine development and chemotherapy strategies [...].
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- 2022
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22. Consistency of Mycobacterium tuberculosis Complex Spoligotyping between the Membrane-Based Method and In Silico Approach.
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Genestet C, Hodille E, Bernard A, Vallée M, Lina G, Le Meur A, Refrégier G, and Dumitrescua O
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- Bacterial Typing Techniques, Genotype, Humans, Polymerase Chain Reaction, Repetitive Sequences, Nucleic Acid, Whole Genome Sequencing methods, Mycobacterium tuberculosis classification, Tuberculosis microbiology
- Abstract
To tackle the spread of tuberculosis (TB), epidemiological studies are undertaken worldwide to investigate TB transmission chains. Clustered regulatory interspaced short palindromic repeats (CRISPR) locus diversity, also called spoligotyping, is a widely used genotyping assay for the characterization of Mycobacterium tuberculosis complex (MTBC). We compared herein the spoligotyping of MTBC clinical isolates using a membrane-based method (following an initial PCR step) and whole-genome sequencing (WGS)-based method (i.e., in silico spoligotyping). All MTBC strains isolated at the Lyon University Hospital, France, between November 2016 and December 2020 were included ( n = 597). Spoligotyping profiles were also used for species identification among the MTBC. Outputs of both methods were analyzed, and discrepant results were investigated thanks to CRISPRbuilder-TB. The overall agreement was 85.7%. Spacer discrepancies observed between the methods were due to the insertion of IS6110 within the direct repeat (DR) sequence upstream or downstream of spacers, mutated DR sequences, or truncated spacers. Discrepancies did not impact species identification. Although spoligotyping-based species identification was inconclusive for 29 isolates, SNP-based phylogeny conducted after WGS allowed the identification of 23 M. tuberculosis (Mtb), 2 M. canettii, and 4 mixed MTBC infections. WGS yielded very few discrepancies compared to membrane-based spoligotyping. Overall agreement was significantly improved (92.4%) by the CRISPR locus reconstruction using CRISPRbuilder-TB for the MTBC isolates with the shared international type 53 in silico spoligotyping. A smooth transition from the membrane-based to the in silico -based genotyping of M. tuberculosis isolates is, therefore, possible for TB diagnosis and epidemiologic survey. IMPORTANCE Whole-genome sequencing (WGS) has profoundly transformed the perspectives of tuberculosis (TB) diagnosis, providing a better discriminatory power to determine relatedness between Mycobacterium tuberculosis complex (MTBC) isolates. Previous genotyping approaches, such as spoligotyping consisting of an initial PCR step followed by reverse dot hybridization, are currently being replaced by WGS. Several pipelines have been developed to extract a spoligotype from WGS data ( in silico spoligotyping) allowing for the continuity of MTBC molecular surveys before and after WGS implementation. The present study found very good overall agreement between hybridization to membrane-based spoligotyping and in silico spoligotyping, indicating the possibility of a smooth transition from the traditional to the in silico -based genotyping of MTBC isolates for TB diagnosis and epidemiological survey.
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- 2022
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23. Connection between two historical tuberculosis outbreak sites in Japan, Honshu, by a new ancestral Mycobacterium tuberculosis L2 sublineage.
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Guyeux C, Senelle G, Refrégier G, Bretelle-Establet F, Cambau E, and Sola C
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- 2022
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24. Molecular epidemiology of Mycobacterium tuberculosis in Brazil before the whole genome sequencing era: a literature review.
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Conceição EC, Salvato RS, Gomes KM, Guimarães AEDS, da Conceição ML, Souza E Guimarães RJP, Sharma A, Furlaneto IP, Barcellos RB, Bollela VR, Anselmo LMP, Sisco MC, Niero CV, Ferrazoli L, Refrégier G, Lourenço MCDS, Gomes HM, de Brito AC, Catanho M, Duarte RS, Suffys PN, and Lima KVB
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- Bacterial Typing Techniques, Brazil epidemiology, Genotype, Humans, Molecular Epidemiology, Mycobacterium tuberculosis isolation & purification, Whole Genome Sequencing, Minisatellite Repeats genetics, Mycobacterium tuberculosis genetics, Polymorphism, Restriction Fragment Length genetics
- Abstract
Molecular-typing can help in unraveling epidemiological scenarios and improvement for disease control strategies. A literature review of Mycobacterium tuberculosis transmission in Brazil through genotyping on 56 studies published from 1996-2019 was performed. The clustering rate for mycobacterial interspersed repetitive units - variable tandem repeats (MIRU-VNTR) of 1,613 isolates were: 73%, 33% and 28% based on 12, 15 and 24-loci, respectively; while for RFLP-IS6110 were: 84% among prison population in Rio de Janeiro, 69% among multidrug-resistant isolates in Rio Grande do Sul, and 56.2% in general population in São Paulo. These findings could improve tuberculosis (TB) surveillance and set up a solid basis to build a database of Mycobacterium genomes.
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- 2021
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25. CRISPRbuilder-TB: "CRISPR-builder for tuberculosis". Exhaustive reconstruction of the CRISPR locus in mycobacterium tuberculosis complex using SRA.
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Guyeux C, Sola C, Noûs C, and Refrégier G
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- Genes, Bacterial, Clustered Regularly Interspaced Short Palindromic Repeats, Mycobacterium tuberculosis genetics, Tuberculosis microbiology
- Abstract
Mycobacterium tuberculosis complex (MTC) CRISPR locus diversity has long been studied solely investigating the presence/absence of a known set of spacers. Unveiling the genetic mechanisms of its evolution requires a more exhaustive reconstruction in a large amount of representative strains. In this article, we point out and resolve, with a new pipeline, the problem of CRISPR reconstruction based directly on short read sequences in M. tuberculosis. We first show that the process we set up, that we coin as "CRISPRbuilder-TB" (https://github.com/cguyeux/CRISPRbuilder-TB), allows an efficient reconstruction of simulated or real CRISPRs, even when including complex evolutionary steps like the insertions of mobile elements. Compared to more generalist tools, the whole process is much more precise and robust, and requires only minimal manual investigation. Second, we show that more than 1/3 of the currently complete genomes available for this complex in the public databases contain largely erroneous CRISPR loci. Third, we highlight how both the classical experimental in vitro approach and the basic in silico spoligotyping provided by existing analytic tools miss a whole diversity of this locus in MTC, by not capturing duplications, spacer and direct repeats variants, and IS6110 insertion locations. This description is extended in a second article that describes MTC-CRISPR diversity and suggests general rules for its evolution. This work opens perspectives for an in-depth exploration of M. tuberculosis CRISPR loci diversity and of mechanisms involved in its evolution and its functionality, as well as its adaptation to other CRISPR locus-harboring bacterial species., Competing Interests: The authors have declared that no competing interests exist.
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- 2021
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26. Unexpected diversity of CRISPR unveils some evolutionary patterns of repeated sequences in Mycobacterium tuberculosis.
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Refrégier G, Sola C, and Guyeux C
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- Base Sequence, DNA Transposable Elements, Molecular Epidemiology, Clustered Regularly Interspaced Short Palindromic Repeats genetics, Mycobacterium tuberculosis genetics
- Abstract
Background: Diversity of the CRISPR locus of Mycobacterium tuberculosis complex has been studied since 1997 for molecular epidemiology purposes. By targeting solely the 43 spacers present in the two first sequenced genomes (H37Rv and BCG), it gave a biased idea of CRISPR diversity and ignored diversity in the neighbouring cas-genes., Results: We set up tailored pipelines to explore the diversity of CRISPR-cas locus in Short Reads. We analyzed data from a representative set of 198 clinical isolates as evidenced by well-characterized SNPs. We found a relatively low diversity in terms of spacers: we recovered only the 68 spacers that had been described in 2000. We found no partial or global inversions in the sequences, letting always the Direct Variant Repeats (DVR) in the same order. In contrast, we found an unexpected diversity in the form of: SNPs in spacers and in Direct Repeats, duplications of various length, and insertions at various locations of the IS6110 insertion sequence, as well as blocks of DVR deletions. The diversity was in part specific to lineages. When reconstructing evolutionary steps of the locus, we found no evidence for SNP reversal. DVR deletions were linked to recombination between IS6110 insertions or between Direct Repeats., Conclusion: This work definitively shows that CRISPR locus of M. tuberculosis did not evolve by classical CRISPR adaptation (incorporation of new spacers) since the last most recent common ancestor of virulent lineages. The evolutionary mechanisms that we discovered could be involved in bacterial adaptation but in a way that remains to be identified.
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- 2020
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27. Spoligotyping of Mycobacterium tuberculosis isolates using Luminex®-based method in Lebanon.
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Masoud K, Araj GF, Reslan L, Fadlallah S, Wehbe M, Itani L, Avedissian A, Dbaibo G, Saade A, Refrégier G, Sola C, and Matar GM
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- Genotype, Humans, Lebanon, Mycobacterium tuberculosis isolation & purification, Polymerase Chain Reaction methods, Bacterial Typing Techniques instrumentation, Mycobacterium tuberculosis genetics, Tuberculosis microbiology
- Abstract
Introduction: Data about the genotypes of circulating Mycobacterium tuberculosis isolates (MTB) in Lebanon are scarce. This study was undertaken to reveal the spoligotypes of MTB isolates recovered from patients in Lebanon., Methodology: MTB isolates from 49 patients living in Lebanon were recovered and identified. The samples were heat killed and subjected to DNA extraction. Spoligotyping was performed using microbeads from TB-SPOL Kit and the fluorescence intensity was measured using Luminex 200®. Generated patterns were assigned to families using the SITVIT2 international database of the Pasteur Institute of Guadeloupe and compared., Results: The spoligotyping of the 49 MTB isolates revealed that 31 isolates belonged to Lineage 4 (Euro-American, 63.3%), 12 to Lineage 3 (East- African Indian, 24.5%), 3 to Lineage 2 (East Asian, 6%) and 2 were unknown. Over half of the genotypes (16 of 30) harbored SIT127 supposed to belong to the L4.5 sublineage. One isolate belonging to the rare Manu-Ancestor SIT523 was recovered for the first time in Lebanon, being associated with highly virulent extensively drug-resistant (XDR) MTB phenotype., Conclusion: The application of the Spoligotyping Multiplex Luminex® method is an efficient, discriminatory and rapid method to use for first-lane genotyping of MTB isolates. Though humble numbers were tested, this study is one of the first to describe the genomic diversity and epidemiology of MTB isolates of Lebanon, and suggests an increasing prevalence of SIT127 in the country., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2020 Khaldoun Masoud, George F Araj, Lina Reslan, Sukayna Fadlallah, Michel Wehbe, Lina Itani, Aline Avedissian, Ghassan Dbaibo, Antoine Saade, Guislaine Refrégier, Christophe Sola, Ghassan M Matar.)
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- 2020
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28. NTF-RINT, a new method for the epidemiological surveillance of MDR Mycobacterium tuberculosis L2/Beijing strains.
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Klotoe BJ, Kurepina N, Zholdibayeva E, Panaiotov S, Kreiswirth BN, Anthony R, Sola C, and Refrégier G
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- DNA Mutational Analysis, Genotype, Humans, Kazakhstan epidemiology, Molecular Epidemiology, Mycobacterium tuberculosis pathogenicity, New York City epidemiology, Phenotype, Polymerase Chain Reaction, Population Surveillance, Predictive Value of Tests, Reproducibility of Results, Tuberculosis, Multidrug-Resistant epidemiology, Tuberculosis, Multidrug-Resistant genetics, Virulence, Bacteriological Techniques, DNA Transposable Elements, DNA, Bacterial genetics, Drug Resistance, Multiple, Bacterial genetics, High-Throughput Nucleotide Sequencing, Mutation, Mycobacterium tuberculosis genetics, Tuberculosis, Multidrug-Resistant diagnosis
- Abstract
The most widely discussed antibiotic-resistant tuberculosis strains ("W" and "B0/W148", "CAO") belong to L2/Beijing Lineage and are characterized by IS6110 insertion sequences at the NTF locus. We present a high-throughput, microbead-based method, called NTF-RINT for detection of IS in NTF and Rifampicin and Isoniazid Typing. This method provides tuberculosis diagnostic confirmation, screens for the so-called modern L2/Beijing sublineage and detects mutations involved in resistance to Rifampicin (RIF) and Isoniazid (INH)., Competing Interests: Declaration of competing interest Bernice Klotoe was partly founded by Beamedex®, a society that sells microbead-based kits. The society had however no part in the decision of what new tests could be set-up and this was entirely decided by public researchers Christophe Sola, Guislaine Refrégier, with the consent of Natalia Kurepina and Barry N. Kreiswirth. Guislaine Refrégier acknowledges one travel grant by Luminex® on another project regarding SNP detection. Luminex® is a manufacturer of microbead-based instruments and microbeads., (Copyright © 2019. Published by Elsevier Ltd.)
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- 2020
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29. Diversity of Mycobacterium tuberculosis in the Middle Fly District of Western Province, Papua New Guinea: microbead-based spoligotyping using DNA from Ziehl-Neelsen-stained microscopy preparations.
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Guernier-Cambert V, Diefenbach-Elstob T, Klotoe BJ, Burgess G, Pelowa D, Dowi R, Gula B, McBryde ES, Refrégier G, Rush C, Sola C, and Warner J
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- Adult, Female, Humans, Male, Molecular Epidemiology, Papua New Guinea epidemiology, Prospective Studies, DNA, Bacterial genetics, Genetic Variation, Genotype, Mycobacterium tuberculosis genetics, Sputum microbiology, Tuberculosis epidemiology, Tuberculosis genetics
- Abstract
Tuberculosis remains the world's leading cause of death from an infectious agent, and is a serious health problem in Papua New Guinea (PNG) with an estimated 36,000 new cases each year. This study describes the genetic diversity of Mycobacterium tuberculosis among tuberculosis patients in the Balimo/Bamu region in the Middle Fly District of Western Province in PNG, and investigates rifampicin resistance-associated mutations. Archived Ziehl-Neelsen-stained sputum smears were used to conduct microbead-based spoligotyping and assess genotypic resistance. Among the 162 samples included, 80 (49.4%) generated spoligotyping patterns (n = 23), belonging predominantly to the L2 Lineage (44%) and the L4 Lineage (30%). This is consistent with what has been found in other PNG regions geographically distant from Middle Fly District of Western Province, but is different from neighbouring South-East Asian countries. Rifampicin resistance was identified in 7.8% of the successfully sequenced samples, with all resistant samples belonging to the L2/Beijing Lineage. A high prevalence of mixed L2/L4 profiles was suggestive of polyclonal infection in the region, although this would need to be confirmed. The method described here could be a game-changer in resource-limited countries where large numbers of archived smear slides could be used for retrospective (and prospective) studies of M. tuberculosis genetic epidemiology.
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- 2019
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30. TB-EFI, a novel 18-Plex microbead-based method for prediction of second-line drugs and ethambutol resistance in Mycobacterium tuberculosis complex.
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Klotoe BJ, Molina-Moya B, Gomes HM, Gomgnimbou MK, Oliveira Suzarte L, Féres Saad MH, Ali S, Dominguez J, Pimkina E, Zholdybayeva E, Sola C, and Refrégier G
- Subjects
- Alleles, Antitubercular Agents therapeutic use, DNA, Bacterial genetics, Fluoroquinolones pharmacology, Genotype, Genotyping Techniques, Humans, Microbial Sensitivity Tests methods, Microfluidics methods, Mutation, Mycobacterium tuberculosis genetics, Pentosyltransferases, Sensitivity and Specificity, Antitubercular Agents pharmacology, Diagnostic Tests, Routine methods, Ethambutol pharmacology, Microspheres, Mycobacterium tuberculosis drug effects, Mycobacterium tuberculosis isolation & purification, Tuberculosis, Multidrug-Resistant diagnosis
- Abstract
Several diagnostic tests are being developed to detect drug resistance in tuberculosis. In line with previous developments detecting rifampicin and isoniazid resistance using microbead-based systems (spoligoriftyping and TB-SPRINT), we present here an assay called TB-EFI detecting mutations involved in resistance to ethambutol, fluoroquinolones and the three classical injectable drugs (kanamycin, amikacin and capreomycin) in Mycobacterium tuberculosis. The proposed test includes both wild-type and mutant probes for each targeted locus. Basic analysis can be performed manually. An upgraded interpretation is made available in Excel 2016®. Using a reference set of 61 DNA extracts, we show that TB-EFI provides perfect concordance with pyrosequencing. Concordance between genotypic resistance and phenotypic DST was relatively good (72 to 98% concordance), with lower efficiency for fluoroquinolones and ethambutol due to some untargeted mutations. When compared to phenotypical resistance, performances were similar to those obtained with Hain MTBDRsl assay, possibly thanks to the use of automatized processing of data although some mutations involved in fluoroquinolone resistance could not be included. When applied on three uncharacterized sets, phenotype could be predicted for 51% to 98% depending on the setting and the drug investigated, detecting one extensively drug-resistant isolate in each of a Pakistan and a Brazilian set of 91 samples, and 9 XDR among 43 multi-resistant Kazakhstan samples. By allowing high-throughput detection of second-line drugs resistance and of resistance to ethambutol that is often combined to second-line treatments, TB-EFI is a cost-effective assay for large-scale worldwide surveillance of resistant tuberculosis and XDR-TB control., (Copyright © 2018 Elsevier B.V. All rights reserved.)
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- 2018
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31. Molecular Characterization of Mycobacterium tuberculosis Strains with TB-SPRINT.
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Molina-Moya B, Gomgnimbou MK, Lafoz C, Lacoma A, Prat C, Refrégier G, Samper S, Dominguez J, and Sola C
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- Genotype, Microbial Sensitivity Tests methods, Molecular Typing methods, Sensitivity and Specificity, Antitubercular Agents pharmacology, Drug Resistance, Multiple, Bacterial genetics, Isoniazid pharmacology, Mycobacterium tuberculosis drug effects, Rifampin pharmacology
- Abstract
We evaluated Tuberculosis-Spoligo-Rifampicin-Isoniazid Typing (TB-SPRINT), a microbead-based method for spoligotyping and detection of rifampicin and isoniazid resistance in Mycobacterium tuberculosis . For that, 67 M. tuberculosis complex strains were retrospectively selected. Membrane-based spoligotyping, restriction fragment length polymorphism, DNA sequencing/pyrosequencing of rpoB , katG , and inhA promoter, TB-SPRINT, and SNP typing were performed. Concordance between spoligotyping methods was 99.6% (2,785/2,795 spoligotype data points). For most of the discordant cases, the same lineage was assigned with both methods. Concordance between phenotypic drug susceptibility testing and TB-SPRINT for detecting rifampicin and isoniazid resistance was 98.4% (63/64) and 93.8% (60/64), respectively. Concordance between DNA sequencing/pyrosequencing and TB-SPRINT for detecting mutations in rpoB , katG , and inhA were 98.4% (60/61), 100% (64/64), and 96.9% (62/64), respectively. In conclusion, TB-SPRINT is a rapid and easy-to-perform assay for genotyping and detecting drug resistance in a single tube; therefore, it may be a useful tool to improve epidemiological surveillance.
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- 2017
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32. Assessment of tuberculosis spatial hotspot areas in Antananarivo, Madagascar, by combining spatial analysis and genotyping.
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Ratovonirina NH, Rakotosamimanana N, Razafimahatratra SL, Raherison MS, Refrégier G, Sola C, Rakotomanana F, and Rasolofo Razanamparany V
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- Genetic Variation, Genotype, Humans, Madagascar epidemiology, Mycobacterium tuberculosis isolation & purification, Spatial Analysis, Sputum microbiology, Mycobacterium tuberculosis genetics, Tuberculosis, Pulmonary epidemiology
- Abstract
Background: Tuberculosis (TB) remains a public health problem in Madagascar. A crucial element of TB control is the development of an easy and rapid method for the orientation of TB control strategies in the country. Our main objective was to develop a TB spatial hotspot identification method by combining spatial analysis and TB genotyping method in Antananarivo., Methods: Sputa of new pulmonary TB cases from 20 TB diagnosis and treatment centers (DTCs) in Antananarivo were collected from August 2013 to May 2014 for culture. Mycobacterium tuberculosis complex (MTBC) clinical isolates were typed by spoligotyping on a Luminex® 200 platform. All TB patients were respectively localized according to their neighborhood residence and the spatial distribution of all pulmonary TB patients and patients with genotypic clustered isolates were scanned respectively by the Kulldorff spatial scanning method for identification of significant spatial clustering. Areas exhibiting spatial clustering of patients with genotypic clustered isolates were considered as hotspot TB areas for transmission., Results: Overall, 467 new cases were included in the study, and 394 spoligotypes were obtained (84.4%). New TB cases were distributed in 133 of the 192 Fokontany (administrative neighborhoods) of Antananarivo (1 to 15 clinical patients per Fokontany) and patients with genotypic clustered isolates were distributed in 127 of the 192 Fokontany (1 to 13 per Fokontany). A single spatial focal point of epidemics was detected when ignoring genotypic data (p = 0.039). One Fokontany of this focal point and three additional ones were detected to be spatially clustered when taking genotypes into account (p < 0.05). These four areas were declared potential TB transmission hotspots in Antananarivo and will be considered as priority targets for surveillance in the future., Conclusion: This method, combining spatial analysis and TB genotyping will now be used for further focused clinical and epidemiological studies in Madagascar and will allow better TB control strategies by public health authorities.
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- 2017
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33. Quick and cheap MIRU-VNTR typing of Mycobacterium tuberculosis species complex using duplex PCR.
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Yasmin M, Le Moullec S, Siddiqui RT, De Beer J, Sola C, and Refrégier G
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- DNA, Bacterial genetics, Electrophoresis, Agar Gel methods, Genotyping Techniques methods, Humans, Minisatellite Repeats genetics, Multiplex Polymerase Chain Reaction methods, Tuberculosis microbiology, Bacterial Typing Techniques methods, Mycobacterium tuberculosis classification, Mycobacterium tuberculosis genetics
- Abstract
While minisatellites are usually typed using capillary sequencers or qiaplex systems in developed countries, many low-resource regions cannot afford it. We propose an optimized agarose gel electrophoresis method to genotype Mycobacterium tuberculosis species complex minisatellites in their standardized format (24 MIRU-VNTR). It is based on duplex PCRs combining VNTR loci harboring distinct amplicon sizes whatever the repetition number of each locus. This method performs well both on DNA extracts of good quality and on thermolysates while reducing workload and reagents costs., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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34. Turkish and Japanese Mycobacterium tuberculosis sublineages share a remote common ancestor.
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Refrégier G, Abadia E, Matsumoto T, Ano H, Takashima T, Tsuyuguchi I, Aktas E, Cömert F, Gomgnimbou MK, Panaiotov S, Phelan J, Coll F, McNerney R, Pain A, Clark TG, and Sola C
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- DNA, Bacterial analysis, DNA, Bacterial genetics, Epidemics history, Epidemics statistics & numerical data, Evolution, Molecular, Genotype, History, 16th Century, History, 17th Century, History, 18th Century, History, Ancient, History, Medieval, Humans, Japan, Minisatellite Repeats genetics, Molecular Epidemiology, Molecular Typing, Phylogeny, Polymorphism, Single Nucleotide genetics, Tuberculosis history, Turkey, Mycobacterium tuberculosis classification, Mycobacterium tuberculosis genetics, Tuberculosis epidemiology, Tuberculosis microbiology
- Abstract
Two geographically distant M. tuberculosis sublineages, Tur from Turkey and T3-Osaka from Japan, exhibit partially identical genotypic signatures (identical 12-loci MIRU-VNTR profiles, distinct spoligotyping patterns). We investigated T3-Osaka and Tur sublineages characteristics and potential genetic relatedness, first using MIRU-VNTR locus analysis on 21 and 25 samples of each sublineage respectively, and second comparing Whole Genome Sequences of 8 new samples to public data from 45 samples uncovering human tuberculosis diversity. We then tried to date their Most Recent Common Ancestor (MRCA) using three calibrations of SNP accumulation rate (long-term=0.03SNP/genome/year, derived from a tuberculosis ancestor of around 70,000years old; intermediate=0.2SNP/genome/year derived from a Peruvian mummy; short-term=0.5SNP/genome/year). To disentangle between these scenarios, we confronted the corresponding divergence times with major human history events and knowledge on human genetic divergence. We identified relatively high intrasublineage diversity for both T3-Osaka and Tur. We definitively proved their monophyly; the corresponding super-sublineage (referred to as "T3-Osa-Tur") shares a common ancestor with T3-Ethiopia and Ural sublineages but is only remotely related to other Euro-American sublineages such as X, LAM, Haarlem and S. The evolutionary scenario based on long-term evolution rate being valid until T3-Osa-Tur MRCA was not supported by Japanese fossil data. The evolutionary scenario relying on short-term evolution rate since T3-Osa-Tur MRCA was contradicted by human history and potential traces of past epidemics. T3-Osaka and Tur sublineages were found likely to have diverged between 800y and 2000years ago, potentially at the time of Mongol Empire. Altogether, this study definitively proves a strong genetic link between Turkish and Japanese tuberculosis. It provides a first hypothesis for calibrating TB Euro-American lineage molecular clock; additional studies are needed to reliably date events corresponding to intermediate depths in tuberculosis phylogeny., (Copyright © 2016 Elsevier B.V. All rights reserved.)
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- 2016
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35. Genomics and Machine Learning for Taxonomy Consensus: The Mycobacterium tuberculosis Complex Paradigm.
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Azé J, Sola C, Zhang J, Lafosse-Marin F, Yasmin M, Siddiqui R, Kremer K, van Soolingen D, and Refrégier G
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- Algorithms, Bacterial Typing Techniques methods, Cluster Analysis, Computational Biology, DNA, Bacterial genetics, Databases, Genetic, Genotype, Internet, Molecular Epidemiology, Polymerase Chain Reaction, Polymorphism, Restriction Fragment Length, Polymorphism, Single Nucleotide, Prevalence, Genomics, Machine Learning, Mycobacterium tuberculosis classification, Tuberculosis microbiology
- Abstract
Infra-species taxonomy is a prerequisite to compare features such as virulence in different pathogen lineages. Mycobacterium tuberculosis complex taxonomy has rapidly evolved in the last 20 years through intensive clinical isolation, advances in sequencing and in the description of fast-evolving loci (CRISPR and MIRU-VNTR). On-line tools to describe new isolates have been set up based on known diversity either on CRISPRs (also known as spoligotypes) or on MIRU-VNTR profiles. The underlying taxonomies are largely concordant but use different names and offer different depths. The objectives of this study were 1) to explicit the consensus that exists between the alternative taxonomies, and 2) to provide an on-line tool to ease classification of new isolates. Genotyping (24-VNTR, 43-spacers spoligotypes, IS6110-RFLP) was undertaken for 3,454 clinical isolates from the Netherlands (2004-2008). The resulting database was enlarged with African isolates to include most human tuberculosis diversity. Assignations were obtained using TB-Lineage, MIRU-VNTRPlus, SITVITWEB and an algorithm from Borile et al. By identifying the recurrent concordances between the alternative taxonomies, we proposed a consensus including 22 sublineages. Original and consensus assignations of the all isolates from the database were subsequently implemented into an ensemble learning approach based on Machine Learning tool Weka to derive a classification scheme. All assignations were reproduced with very good sensibilities and specificities. When applied to independent datasets, it was able to suggest new sublineages such as pseudo-Beijing. This Lineage Prediction tool, efficient on 15-MIRU, 24-VNTR and spoligotype data is available on the web interface "TBminer." Another section of this website helps summarizing key molecular epidemiological data, easing tuberculosis surveillance. Altogether, we successfully used Machine Learning on a large dataset to set up and make available the first consensual taxonomy for human Mycobacterium tuberculosis complex. Additional developments using SNPs will help stabilizing it.
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- 2015
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36. Molecular epidemiology of tuberculosis in Sicily, Italy: what has changed after a decade?
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Bonura C, Gomgnimbou MK, Refrégier G, Aleo A, Fasciana T, Giammanco A, Sola C, and Mammina C
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- Adult, Antibiotics, Antitubercular pharmacology, Drug Resistance, Bacterial physiology, Ethambutol pharmacology, Female, Genotype, Humans, Isoniazid pharmacology, Male, Microbial Sensitivity Tests, Middle Aged, Minisatellite Repeats, Molecular Epidemiology, Molecular Typing, Mycobacterium tuberculosis drug effects, Mycobacterium tuberculosis physiology, Rifampin pharmacology, Sicily epidemiology, Tuberculosis epidemiology, Mycobacterium tuberculosis genetics, Tuberculosis microbiology
- Abstract
Background: We aimed to investigate the molecular epidemiology of Mycobacterium tuberculosis complex (MTBC) isolates in the province of Palermo, Sicily, Italy, by characterizing 183 isolates identified in the years 2004-2012. A comparison with 104 MTBC strains identified in the same geographic area in the years 1994-2000 was also carried out., Methods: One hundred eighty-three MTBC isolates identified in Palermo, Italy, in the years 2004-2012 were analyzed by spoligotyping and the 24 mycobacterial interspersed repetitive unit (MIRU)-variable-number tandem-repeat (VNTR) method typing. Susceptibility testing to streptomycin, isoniazid, rifampin and ethambutol was also performed. Furthermore, the spoligotyping dataset obtained from 104 MTBC isolates identified from 1994 to 2000 was reanalyzed. Distribution into lineages and clustering of isolates in the two periods was compared., Results: One hundred seventy-seven out of the 183 isolates of MTBC submitted to molecular typing were fully characterized. Of these, 108 were from Italian-born and 69 from foreign-born individuals. Eleven different lineages and 35 families-subfamilies were identified with the most represented lineages being Haarlem (26.5%), T (19.2%), LAM (13.6%) and S (8.5%). Except for the Haarlem lineage, where isolates from foreign-born patients were overrepresented, the distribution of isolates in the families belonging to the Euro-American clone reflected the proportions of the two subpopulations. A total of 27 (15.2%) strains were clustered and three clusters were mixed. Approximately 25% of the 183 MTBC isolates under study proved to be resistant to at least one antiTB drug, with only three isolates categorized as multidrug resistant (MDR). When MTBC isolates identified in the years 1994-2000 were reanalyzed, lineages T (30.8%), LAM (29.8%), Haarlem (16.3%) and S (13.5%) proved to be predominant. No MTBC isolates belonging to CAM, U, CAS, Turkish and Ural lineages were identified., Conclusions: A wide heterogeneity was detected among the MTBC strains isolated in the years 2004-2012. Six lineages were not present among the isolates of the period 1994-2000. Comparison between distribution of lineages in the two consecutive periods depicts rapid and deep changes in the TB epidemiology in Palermo, Italy. An universal and continued laboratory-based surveillance of TB in Sicily is required.
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- 2014
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37. Multi-drug resistant Mycobacterium tuberculosis complex genetic diversity and clues on recent transmission in Punjab, Pakistan.
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Yasmin M, Gomgnimbou MK, Siddiqui RT, Refrégier G, and Sola C
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- Antitubercular Agents pharmacology, Cluster Analysis, Genotype, Geography, Humans, Microbial Sensitivity Tests, Minisatellite Repeats, Multilocus Sequence Typing, Mutation, Mycobacterium tuberculosis classification, Pakistan epidemiology, Tuberculosis, Multidrug-Resistant epidemiology, Drug Resistance, Multiple, Bacterial genetics, Genetic Variation, Mycobacterium tuberculosis genetics, Tuberculosis, Multidrug-Resistant microbiology, Tuberculosis, Multidrug-Resistant transmission
- Abstract
Multi-Drug Resistant Tuberculosis (MDR-TB), i.e. bacilli resistant to rifampicin (RIF) and isoniazid (INH), is a major Public Health concern in Pakistan according to WHO estimates (3.5% and 32% of new and retreated cases, respectively). Previous Pakistanis reports identified a correlation between being MDR and belonging to Beijing or EAI lineages in one study, and belonging to "H4"-Ural Euro-American sublineage in another study. In addition, MDR-TB transmission was suspected in Karachi. We tested MDR characteristics on a Punjab sample of 278 clinical isolates (without selection for Multi-Drug Resistance) including new and retreated cases collected from 2008 to 2012. All samples were characterized by a new, microbead-based method named "TB-SPRINT" (molecular diagnostic including spoligotype identification, and genetic resistance determinants to first-line anti-TB drugs RIF and INH). Isolates from 2011 to 2012 (n=100) were further analyzed using 24-loci MIRU-VNTR. We detected 8.7% MDR isolates (CI95%=[5.0; 12.5]), mainly among CAS lineage that predominates in this central-East region of Pakistan. Out of 20 MDR-TB cases, 12 different TB-SPRINT profiles were identified, limiting the suspicion of MDR-TB transmission. 24 MIRU-VNTR confirmed the unrelatedness of isolates with different TB-SPRINT profiles and discriminated 3 isolates with identical TB-SPRINT profiles. In conclusion, our study did not confirm any of the correlations between Multi-Drug Resistance and lineage or sublineage in Punjab, Pakistan. MDR-TB isolates were diverse indicating that transmission is not pervasive. TB-SPRINT proved useful as a first step for detecting MDR-TB likely transmission events, before more extensive genotyping such as 15 or 24 MIRU-VNTR and thorough epidemiological investigation., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2014
- Full Text
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38. Validation of a microbead-based format for spoligotyping of Legionella pneumophila.
- Author
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Gomgnimbou MK, Ginevra C, Peron-Cane C, Versapuech M, Refrégier G, Jacotin N, Sola C, and Jarraud S
- Subjects
- Automation, Laboratory, France, High-Throughput Screening Assays, Humans, Molecular Epidemiology methods, Legionella pneumophila classification, Legionella pneumophila genetics, Microspheres, Molecular Typing methods
- Abstract
A 42-plex clustered regularly interspaced short palindromic repeat (CRISPR)-based typing technique (spoligotyping) was recently developed at the French National Reference Center for Legionella. It allows the subtyping of the Legionella pneumophila sequence type 1/Paris pulsotype. In this report, we present the transfer of the membrane-based spoligotyping technique to a microbead-based multiplexed format. This microbead-based high-throughput assay uses devices such as Luminex 200 or the recently launched Magpix system (Luminex Corp., Austin, TX). We designated this new technique LP-SPOL (for L. pneumophila spoligotyping). We used two sets of samples previously subtyped by the membrane-based spoligotyping method to set up and validate the transfer on the two microbead-based systems. The first set of isolates (n = 56) represented the whole diversity of the CRISPR patterns known to date. These isolates were used for transfer setup (determination of spacer cutoffs for both devices). The second set of isolates (n = 245) was used to validate the transfer to the two microbead-based systems. The results obtained by the Luminex 200 system were 100% concordant with those obtained by the Magpix system for the 2 sets of isolates. In total, 10 discrepant results were observed when comparing the membrane-based method to the microbead-based method. These discrepancies were further resolved by repeating either the membrane-based or the microbead-based assay. This new assay is expected to play an emerging role for surveillance of L. pneumophila, starting with one of the most frequent genotypes, the sequence type 1/Paris pulsotype. However, the generalization of this typing method to all L. pneumophila strains is not feasible, since not all L. pneumophila strains contain CRISPRs., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)
- Published
- 2014
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39. "Spoligoriftyping," a dual-priming-oligonucleotide-based direct-hybridization assay for tuberculosis control with a multianalyte microbead-based hybridization system.
- Author
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Gomgnimbou MK, Abadia E, Zhang J, Refrégier G, Panaiotov S, Bachiyska E, and Sola C
- Subjects
- Antitubercular Agents pharmacology, Bulgaria, DNA-Directed RNA Polymerases genetics, Drug Resistance, Bacterial, Genotype, Germany, Humans, Microbial Sensitivity Tests methods, Microspheres, Mycobacterium tuberculosis drug effects, Nigeria, Oligonucleotides genetics, Rifampin pharmacology, Tuberculosis, Multidrug-Resistant diagnosis, Molecular Typing methods, Mycobacterium tuberculosis classification, Mycobacterium tuberculosis genetics, Nucleic Acid Hybridization methods, Tuberculosis, Multidrug-Resistant microbiology
- Abstract
We developed "spoligoriftyping," a 53-plex assay based on two preexisting methods, the spoligotyping and "rifoligotyping" assays, by combining them into a single assay. Spoligoriftyping allows simultaneous spoligotyping (i.e., clustered regularly interspaced short palindromic repeat [CRISPR]-based genotyping) and characterization of the main rifampin drug resistance mutations on the rpoB hot spot region in a few hours. This test partly uses the dual-priming-oligonucleotide (DPO) principle, which allows simultaneous efficient amplifications of rpoB and the CRISPR locus in the same sample. We tested this method on a set of 114 previously phenotypically and genotypically characterized multidrug-resistant (MDR) Mycobacterium tuberculosis or drug-susceptible M. tuberculosis DNA extracted from clinical isolates obtained from patients from Bulgaria, Nigeria, and Germany. We showed that our method is 100% concordant with rpoB sequencing results and 99.95% (3,911/3,913 spoligotype data points) correlated with classical spoligotyping results. The sensitivity and specificity of our assay were 99 and 100%, respectively, compared to those of phenotypic drug susceptibility testing. Such assays pave the way to the implementation of locally and specifically adapted methods of performing in a single tube both drug resistance mutation detection and genotyping in a few hours.
- Published
- 2012
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40. A molecular epidemiological and genetic diversity study of tuberculosis in Ibadan, Nnewi and Abuja, Nigeria.
- Author
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Lawson L, Zhang J, Gomgnimbou MK, Abdurrahman ST, Le Moullec S, Mohamed F, Uzoewulu GN, Sogaolu OM, Goh KS, Emenyonu N, Refrégier G, Cuevas LE, and Sola C
- Subjects
- Adolescent, Adult, Aged, Cluster Analysis, Evolution, Molecular, Female, Genotype, Humans, Male, Middle Aged, Multilocus Sequence Typing, Mycobacterium tuberculosis classification, Mycobacterium tuberculosis isolation & purification, Nigeria epidemiology, Phylogeny, Tuberculosis transmission, Tuberculosis, Multidrug-Resistant genetics, Young Adult, Genetic Variation, Mycobacterium tuberculosis genetics, Tuberculosis epidemiology
- Abstract
Background: Nigeria has the tenth highest burden of tuberculosis (TB) among the 22 TB high-burden countries in the world. This study describes the biodiversity and epidemiology of drug-susceptible and drug-resistant TB in Ibadan, Nnewi and Abuja, using 409 DNAs extracted from culture positive TB isolates., Methodology/principal Findings: DNAs extracted from clinical isolates of Mycobacterium tuberculosis complex were studied by spoligotyping and 24 VNTR typing. The Cameroon clade (CAM) was predominant followed by the M. africanum (West African 1) and T (mainly T2) clades. By using a smooth definition of clusters, 32 likely epi-linked clusters related to the Cameroon genotype family and 15 likely epi-linked clusters related to other "modern" genotypes were detected. Eight clusters concerned M. africanum West African 1. The recent transmission rate of TB was 38%. This large study shows that the recent transmission of TB in Nigeria is high, without major regional differences, with MDR-TB clusters. Improvement in the TB control programme is imperative to address the TB control problem in Nigeria.
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- 2012
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41. Rapidly evolving genes in pathogens: methods for detecting positive selection and examples among fungi, bacteria, viruses and protists.
- Author
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Aguileta G, Refrégier G, Yockteng R, Fournier E, and Giraud T
- Subjects
- Animals, Genetic Linkage, Host-Pathogen Interactions genetics, Models, Genetic, Toxins, Biological genetics, Bacteria genetics, Eukaryota genetics, Evolution, Molecular, Fungi genetics, Selection, Genetic, Viruses genetics
- Abstract
The ongoing coevolutionary struggle between hosts and pathogens, with hosts evolving to escape pathogen infection and pathogens evolving to escape host defences, can generate an 'arms race', i.e., the occurrence of recurrent selective sweeps that each favours a novel resistance or virulence allele that goes to fixation. Host-pathogen coevolution can alternatively lead to a 'trench warfare', i.e., balancing selection, maintaining certain alleles at loci involved in host-pathogen recognition over long time scales. Recently, technological and methodological progress has enabled detection of footprints of selection directly on genes, which can provide useful insights into the processes of coevolution. This knowledge can also have practical applications, for instance development of vaccines or drugs. Here we review the methods for detecting genes under positive selection using divergence data (i.e., the ratio of nonsynonymous to synonymous substitution rates, d(N)/d(S)). We also review methods for detecting selection using polymorphisms, such as methods based on F(ST) measures, frequency spectrum, linkage disequilibrium and haplotype structure. In the second part, we review examples where targets of selection have been identified in pathogens using these tests. Genes under positive selection in pathogens have mostly been sought among viruses, bacteria and protists, because of their paramount importance for human health. Another focus is on fungal pathogens owing to their agronomic importance. We finally discuss promising directions in pathogen studies, such as detecting selection in non-coding regions.
- Published
- 2009
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42. Speciation in fungi.
- Author
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Giraud T, Refrégier G, Le Gac M, de Vienne DM, and Hood ME
- Subjects
- Chromosomes, Fungal, Epigenesis, Genetic, Evolution, Molecular, Fungi isolation & purification, Fungi physiology, Host-Pathogen Interactions, Species Specificity, Fungi genetics, Genetic Speciation
- Abstract
In this review on fungal speciation, we first contrast the issues of species definition and species criteria and show that by distinguishing the two concepts the approaches to studying the speciation can be clarified. We then review recent developments in the understanding of modes of speciation in fungi. Allopatric speciation raises no theoretical problem and numerous fungal examples exist from nature. We explain the theoretical difficulties raised by sympatric speciation, review the most recent models, and provide some natural examples consistent with speciation in sympatry. We describe the nature of prezygotic and postzygotic reproductive isolation in fungi and examine their evolution as functions of temporal and of the geographical distributions. We then review the theory and evidence for roles of cospeciation, host shifts, hybridization, karyotypic rearrangement, and epigenetic mechanisms in fungal speciation. Finally, we review the available data on the genetics of speciation in fungi and address the issue of speciation in asexual species.
- Published
- 2008
- Full Text
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43. Mating system of the anther smut fungus Microbotryum violaceum: selfing under heterothallism.
- Author
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Giraud T, Yockteng R, López-Villavicencio M, Refrégier G, and Hood ME
- Subjects
- Basidiomycota classification, Basidiomycota cytology, Basidiomycota genetics, Cell Division, Chromosomes, Fungal, Host-Pathogen Interactions, Basidiomycota physiology, Caryophyllaceae microbiology, Flowers microbiology, Genes, Mating Type, Fungal, Plant Diseases microbiology
- Published
- 2008
- Full Text
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44. Interaction between wall deposition and cell elongation in dark-grown hypocotyl cells in Arabidopsis.
- Author
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Refrégier G, Pelletier S, Jaillard D, and Höfte H
- Subjects
- Arabidopsis genetics, Arabidopsis ultrastructure, Cell Division physiology, Cell Wall ultrastructure, Cellulose metabolism, Darkness, Hypocotyl ultrastructure, Microfibrils metabolism, Microscopy, Electron, Mutation, Arabidopsis growth & development, Cell Wall metabolism, Hypocotyl growth & development
- Abstract
A central problem in plant biology is how cell expansion is coordinated with wall synthesis. We have studied growth and wall deposition in epidermal cells of dark-grown Arabidopsis hypocotyls. Cells elongated in a biphasic pattern, slowly first and rapidly thereafter. The growth acceleration was initiated at the hypocotyl base and propagated acropetally. Using transmission and scanning electron microscopy, we analyzed walls in slowly and rapidly growing cells in 4-d-old dark-grown seedlings. We observed thick walls in slowly growing cells and thin walls in rapidly growing cells, which indicates that the rate of cell wall synthesis was not coupled to the cell elongation rate. The thick walls showed a polylamellated architecture, whereas polysaccharides in thin walls were axially oriented. Interestingly, innermost cellulose microfibrils were transversely oriented in both slowly and rapidly growing cells. This suggested that transversely deposited microfibrils reoriented in deeper layers of the expanding wall. No growth acceleration, only slow growth, was observed in the cellulose synthase mutant cesA6(prc1-1) or in seedlings, which had been treated with the cellulose synthesis inhibitor isoxaben. In these seedlings, innermost microfibrils were transversely oriented and not randomized as has been reported for other cellulose-deficient mutants or following treatment with dichlorobenzonitrile. Interestingly, isoxaben treatment after the initiation of the growth acceleration in the hypocotyl did not affect subsequent cell elongation. Together, these results show that rapid cell elongation, which involves extensive remodeling of the cell wall polymer network, depends on normal cellulose deposition during the slow growth phase.
- Published
- 2004
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45. Resistance against herbicide isoxaben and cellulose deficiency caused by distinct mutations in same cellulose synthase isoform CESA6.
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Desprez T, Vernhettes S, Fagard M, Refrégier G, Desnos T, Aletti E, Py N, Pelletier S, and Höfte H
- Subjects
- Activating Transcription Factors, Alleles, Amino Acid Sequence, Arabidopsis drug effects, Arabidopsis genetics, Chromosome Mapping, Cloning, Molecular, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Dose-Response Relationship, Drug, Drug Resistance genetics, Gene Expression, Genotype, Glucans metabolism, Glucosyltransferases metabolism, Hypocotyl drug effects, Hypocotyl genetics, Hypocotyl growth & development, Isoenzymes genetics, Isoenzymes metabolism, Lignin metabolism, Molecular Sequence Data, Mutation, Missense, Phenotype, Phylogeny, Plant Roots drug effects, Plant Roots genetics, Plant Roots growth & development, Plants, Genetically Modified, Sequence Homology, Amino Acid, Transcription Factors genetics, Transcription Factors metabolism, Transformation, Genetic, Arabidopsis growth & development, Arabidopsis Proteins, Benzamides pharmacology, Cellulose metabolism, Glucosyltransferases genetics, Herbicides pharmacology, Schizosaccharomyces pombe Proteins
- Abstract
Isoxaben is a pre-emergence herbicide that inhibits cellulose biosynthesis in higher plants. Two loci identified by isoxaben-resistant mutants (ixr1-1, ixr1-2, and ixr2-1) in Arabidopsis have been reported previously. IXR1 was recently shown to encode the cellulose synthase catalytic subunit CESA3 (W.-R. Scheible, R. Eshed, T. Richmond, D. Delmer, and C. Somerville [2001] Proc Natl Acad Sci USA 98: 10079-10084). Here, we report on the cloning of IXR2, and show that it encodes another cellulose synthase isoform, CESA6. ixr2-1 carries a mutation substituting an amino acid close to the C terminus of CESA6 that is highly conserved among CESA family members. Transformation of wild-type plants with the mutated gene and not with the wild-type gene conferred increased resistance against the herbicide. The simplest interpretation for the existence of these two isoxaben-resistant loci is that CESA3 and CESA6 have redundant functions. However, loss of function procuste1 alleles of CESA6 were previously shown to have a strong growth defect and reduced cellulose content in roots and dark-grown hypocotyls. This indicates that in these mutants, the presence of CESA3 does not compensate for the absence of CESA6 in roots and dark-grown hypocotyls, which argues against redundant functions for CESA3 and CESA6. Together, these observations are compatible with a model in which CESA6 and CESA3 are active as a protein complex.
- Published
- 2002
- Full Text
- View/download PDF
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