Browsing by Author "Comas, I."

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Evaluation of customised lineage-specific sets of MIRU-VNTR loci for genotyping Mycobacterium tuberculosis complex isolates in Ghana
(Public Library of Science, 2014) Asante-Poku, A.; Nyaho, M.S.; Borrell, S.; Comas, I.; Gagneux, S.; Yeboah-Manu, D.
Background: Different combinations of variable number of tandem repeat (VNTR) loci have been proposed for genotyping Mycobacterium tuberculosis complex (MTBC). Existing VNTR schemes show different discriminatory capacity among the six human MTBC lineages. Here, we evaluated the discriminatory power of a "customized MIRU12" loci format proposed previously by Comas et al. based on the standard 24 loci defined by Supply et al. for VNTR-typing of MTBC in Ghana. Method: One hundred and fifty-eight MTBC isolates classified into Lineage 4 and Lineage 5 were used to compare a customized lineage-specific panel of 12 MIRU-VNTR loci ("customized MIRU-12") to the standard MIRU-15 genotyping scheme. The resolution power of each typing method was determined based on the Hunter-Gaston- Discriminatory Index (HGDI). A minimal set of customized MIRU-VNTR loci for typing Lineages 4 (Euro-American) and 5 (M. africanum West African 1) strains from Ghana was defined based on the cumulative HGDI. Results and Conclusion: Among the 106 Lineage 4 strains, the customized MIRU-12 identified a total of 104 distinct genotypes consisting of 2 clusters of 2 isolates each (clustering rate 1.8%), and 102 unique strains while standard MIRU-15 yielded a total of 105 different genotypes, including 1 cluster of 2 isolates (clustering rate: 0.9%) and 104 singletons. Among, 52 Lineage 5 isolates, customized MIRU-12 genotyping defined 51 patterns with 1 cluster of 2 isolates (clustering rate: 0.9%) and 50 unique strains whereas MIRU-15 classified all 52 strains as unique. Cumulative HGDI values for customized MIRU-12 for Lineages 4 and 5 were 0.98 respectively whilst that of standard MIRU-15 was 0.99. A union of loci from the customised MIRU-12 and standard MIRU-15 revealed a set of customized eight highly discriminatory loci: 4052, 2163B, 40, 4165, 2165, 10,16 and 26 with a cumulative HGDI of 0.99 for genotyping Lineage 4 and 5 strains from Ghana.
Local adaptation in populations of Mycobacterium tuberculosis endemic to the Indian Ocean Rim[version 1; peer review: 3 approved]
(F1000Research, 2021) Menardo, F.; Rutaihwa, L.K.; Zwyer, M.; Borrell, S.; Comas, I.; Conceição, E.C.; Coscolla, M.; Cox, H.; Joloba, M.; Dou, H.; Feldmann, J.; Fenner, L.; Fyfe, J.; Gao, Q.; de Viedma, D.G.; Garcia-Basteiro, A.L.; Gygli, S.M.; Hella, J.; Hiza, H.; Jugheli, L.; Kamwela, L.; Kato-Maeda, M.; Liu, Q.; Ley, S.D.; Loiseau, C.; Mahasirimongkol, S.; Malla, B.; Palittapongarnpim, P.; Rakotosamimanana, N.; Rasolofo, V.; Reinhard, M.; Reither, K.; Sasamalo, M.; Duarte, R.S.; Sola, C.; Suffys, P.; Lima, K.V.B.; Yeboah-Manu, D.; Beisel, C.; Brites, D.; Gagneux, S.
Background: Lineage 1 (L1) and 3 (L3) are two lineages of the Mycobacterium tuberculosis complex (MTBC) causing tuberculosis (TB) in humans. L1 and L3 are prevalent around the rim of the Indian Ocean, the region that accounts for most of the world’s new TB cases. Despite their relevance for this region, L1 and L3 remain understudied. Methods: We analyzed 2,938 L1 and 2,030 L3 whole genome sequences originating from 69 countries. We reconstructed the evolutionary history of these two lineages and identified genes under positive selection. Results: We found a strongly asymmetric pattern of migration from South Asia toward neighboring regions, highlighting the historical role of South Asia in the dispersion of L1 and L3. Moreover, we found that several genes were under positive selection, including genes involved in virulence and resistance to antibiotics . For L1 we identified signatures of local adaptation at the esxH locus, a gene coding for a secreted effector that targets the human endosomal sorting complex, and is included in several vaccine candidates. Conclusions: Our study highlights the importance of genetic diversity in the MTBC, and sheds new light on two of the most important MTBC lineages affecting humans.
Out-of-Africa migration and Neolithic coexpansion of Mycobacterium tuberculosis with modern humans
(Nature Genetics, 2013-09) Comas, I.; Coscolla, M.; Luo, T.; Borrell, S.; Holt, K.E.; Kato-Maeda, M.; Parkhill, J.; Malla, B.; Berg, S.; Thwaites, G.; Yeboah-Manu, D.; Bothamley, G.; Mei, J.; Wei, L.; Bentley, S.; Harris, S.R.; Niemann, S.; Diel, R.; Aseffa, A.; Gao, Q.; Young, D.; Gagneux, S.
Tuberculosis caused 20% of all human deaths in the Western world between the seventeenth and nineteenth centuries and remains a cause of high mortality in developing countries. In analogy to other crowd diseases, the origin of human tuberculosis has been associated with the Neolithic Demographic Transition, but recent studies point to a much earlier origin. We analyzed the whole genomes of 259 M. Tuberculosis complex (MTBC) strains and used this data set to characterize global diversity and to reconstruct the evolutionary history of this pathogen. Coalescent analyses indicate that MTBC emerged about 70,000 years ago, accompanied migrations of anatomically modern humans out of Africa and expanded as a consequence of increases in human population density during the Neolithic period. This long coevolutionary history is consistent with MTBC displaying characteristics indicative of adaptation to both low and high host densities. © 2013 Nature America, Inc. All rights reserved.