11 páginas, 4 figuras, 1 tabla y fórmulas. Plots of all trajectories calculated (Dataset S7) have been deposited in Figshare (https://dx.doi.org/10.6084/m9.figshare.19335854). Previously published data were also used for this work [data from Brites et al. (4), Coll et al. (29), Stucki et al. (30), Guerra-Assunc¸~ao et al. (31), Zignol et al. (32), Bos et al. (33), Ates et al. (34), Comas et al. (10, 35), Borrell et al. (36), and Cancino-Mu~noz et al. (37)]. ; SignificancePrevious attempts to identify the action of natural selection in the Mycobacterium tuberculosis complex (MTBC) were limited by sample size and averaging across time and lineages. We investigate changes in selective pressures across time for every single gene of the MTBC. We developed a methodology to analyze temporal signals of selection in a large dataset (∼5,000 complete genomes) and showed that 1) almost half of the genes seem to have been under positive selection at some point in time; 2) experimentally confirmed epitopes tend to accumulate more mutations in deeper branches than in external branches; and 3) temporal signals identify genes that were conserved in the past but under positive selection in the present, suggesting ongoing adaptation to the host. ; This project received funding from the European Research Council under the European Union's Horizon 2020 Research and Innovation Program Grant 101001038 (TB-RECONNECT). In addition, this work was funded by Ministerio de Ciencia (Spanish Government) Project PID2019- 104477RB-I00 and Generalitat Valenciana Project AICO/2018/113. This research work was also funded by the European Commission – NextGenerationEU (Regulation EU 2020/2094), through CSIC's Global Health Platform (PTI Salud Global) ; Peer reviewed
14 paginas, 5 figuras, 2 tablas. ; Genomic studies of the Mycobacterium tuberculosis complex (MTBC) might shed light on the dynamics of its transmission, especially in high-burden settings, where recent outbreaks are embedded in the complex natural history of the disease. To this end, we conducted a 1 year prospective surveillance-based study in Mozambique. We applied whole-genome sequencing (WGS) to 295 positive cultures. We fully characterized MTBC isolates by phylogenetics and dating evaluation, and carried out a molecular epidemiology analysis to investigate further associations with pre-defined transmission risk factors. The majority of strains (49.5%, 136/275) belonged to lineage (L) 4; 57.8 % of them (159/275) were in genomic transmission clusters (cut-off 5 SNPs), and a strikingly high proportion (45.5%) shared an identical genotype (0 SNP pairwise distance). We found two 'likely endemic' clades, comprising 67 strains, belonging to L1.2, which dated back to the late 19th century and were associated with recent spread among people living with human immunodeficiency virus (PLHIV). We describe for the first time the population structure of MTBC in our region, a high tuberculosis (TB)/HIV burden area. Clustering analysis revealed an unforeseen pattern of spread and high rates of progression to active TB, suggesting weaknesses in TB control activities. The long-term presence of local strains in Mozambique, which were responsible for large transmission among HIV/TB-coinfected patients, calls into question the role of HIV in TB transmission. ; This project received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programmes 101001038 (TB-RECONNECT), PID2019-104477RB-I00 from Ministerio de Economía y Competitividad (Spanish Government) (to I.C.). We acknowledge support from the Spanish Ministry of Science, Innovation and Universities through the 'Centro de Excelencia Severo Ochoa 2019–2023'.Programme (CEX2018-000806-S), and support from the ...
Ruiz-Rodriguez, P.; Frances-Gomez, C.; Chiner-Oms, A.; Lopez, M. G.; Jimenez-Serrano, S.; Cancino-Munoz, I.; Ruiz-Hueso, P.; Torres-Puente, M.; Bracho, M. A.; D'Auria, G.; Martinez-Priego, L.; Guerreiro, M.; Montero-Alonso, M.; Gomez, M. D.; Pinana, J. L.; Seq, Covid-Spain Consortium; Gonzalez-Candelas, F.; Comas, I.; Marina, A.; Geller, R.; Coscolla, M. Evolutionary and Phenotypic Characterization of Two Spike Mutations in European Lineage 20E of SARS-CoV-2 [Preprint] MedRxiv; https://dx.doi.org/10.1101/2021.03.08.21253075 ; We have detected two mutations in the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at amino acid positions 1163 and 1167 that appeared independently in multiple transmission clusters and different genetic backgrounds. Furthermore, both mutations appeared together in a cluster of 1,627 sequences belonging to clade 20E. This cluster is characterized by 12 additional single nucleotide polymorphisms but no deletions. The available structural information on the S protein in the pre- and postfusion conformations predicts that both mutations confer rigidity, which could potentially decrease viral fitness. Accordingly, we observed reduced infectivity of this spike genotype relative to the ancestral 20E sequence in vitro, and the levels of viral RNA in nasopharyngeal swabs were not significantly higher. Furthermore, the mutations did not impact thermal stability or antibody neutralization by sera from vaccinated individuals but moderately reduce neutralization by convalescent-phase sera from the early stages of the pandemic. Despite multiple successful appearances of the two spike mutations during the first year of SARS-CoV-2 evolution, the genotype with both mutations was displaced upon the expansion of the 20I (Alpha) variant. The midterm fate of the genotype investigated was consistent with the lack of advantage observed in the clinical and experimental data. IMPORTANCE We observed repeated, independent emergence of mutations in the SARS-CoV-2 spike involving amino acids 1163 and 1167, within the HR2 functional motif. Conclusions derived from evolutionary and genomic diversity analysis suggest that the co-occurrence of both mutations might pose an advantage for the virus and therefore a threat to effective control of the epidemic. However, biological characterization, including in vitro experiments and analysis of clinical data, indicated no clear benefit in terms of stability or infectivity. In agreement with this, continuous epidemiological surveillance conducted months after the first observations revealed that both mutations did not successfully outcompete other variants and stopped circulating 9 months after their initial detection. Additionally, we evaluated the potential of both mutations to escape neutralizing antibodies, finding that the presence of these two mutations on their own is not likely to confer antibody escape. Our results provide an example of how newly emerged spike mutations can be assessed to better understand the risk posed by new variants and indicate that some spike mutations confer no clear advantage to the virus despite independently emerging multiple times and are eventually displaced by fitter variants. ; This work was funded by the Instituto de Salud Carlos III project COV20/00140 and COV20/00437, Spanish National Research Council project CSIC-COV19-021 and CSIC-COVID19-082, and the Generalitat Valenciana (SEJI/2019/011 and Covid_19-SCI). Action co-financed by the European Union through the Operational Program of the European Regional Development Fund (ERDF) of the Valencian Community 2014-2020. M.C. and R.G. are supported by Ramon y Cajal program from Ministerio de Ciencia. ; Peer reviewed
Molecular epidemiology of SARS-CoV-2 aims to monitor the appearance of new variants with the potential to change the virulence or transmissibility of the virus. During the first year of SARS-CoV-2 evolution, numerous variants with possible public health impact have emerged. We have detected two mutations in the Spike protein at amino acid positions 1163 and 1167 that have appeared independently multiple times in different genetic backgrounds, indicating they may increase viral fitness. Interestingly, the majority of these sequences appear in transmission clusters, with the genotype encoding mutations at both positions increasing in frequency more than single-site mutants. This genetic outcome that we denote as Lineage B.1.177.637, belongs to clade 20E and includes 12 additional single nucleotide polymorphisms but no deletions with respect to the reference genome (first sequence in Wuhan). B.1.177.637 appeared after the first wave of the epidemic in Spain, and subsequently spread to eight additional countries, increasing in frequency among sequences in public databases. Positions 1163 and 1167 of the Spike protein are situated in the HR2 domain, which is implicated in the fusion of the host and viral membranes. To better understand the effect of these mutations on the virus, we examined whether B.1.177.637 altered infectivity, thermal stability, or antibody sensitivity. Unexpectedly, we observed reduced infectivity of this variant relative to the ancestral 20E variant in vitro while the levels of viral RNA in nasopharyngeal swabs did not vary significantly. In addition, we found the mutations do not impact thermal stability or antibody susceptibility in vaccinated individuals but display a moderate reduction in sensitivity to neutralization by convalescent sera from early stages of the pandemic. Altogether, this lineage could be considered a Variant of Interest (VOI), we denote VOI1163.7. Finally, we detected a sub-cluster of sequences within VOI1163.7 that have acquired two additional changes previously associated with antibody escape and it could be identified as VOI1163.7.V2. Overall, we have detected the spread of a new Spike variant that may be advantageous to the virus and whose continuous transmission poses risks by the acquisition of additional mutations that could affect pre-existing immunity. ; This work was funded by the Instituto de Salud Carlos III project COV20/00140 and COV20/00437, Spanish National Research Council project CSIC-COV19-021 and CSIC-COVID19-082, and the Generalitat Valenciana (SEJI/2019/011 and Covid_19-SCI). Action co-financed by the European Union through the Operational Program of the European Regional Development Fund (ERDF) of the Valencian Community 2014-2020. M.C. and R.G. are supported by Ramon y Cajal program from Ministerio de Ciencia. ; No
