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Mycobacteria

Líneas de investigación

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Bacterial Genetics

Our group has been studying for more than 30 years the mechanisms of antibiotic resistance in Streptococcus pneumoniae (Spn). Our objectives are to understand the molecular basis of antimicrobial action, to search for new targets of action and new compounds. Seconeolitsine (SCN) is one of these new compounds targeting topoisomerase I (Topo I). As for the search for new targets, our research has focused in recent years on the factors that organize the topology of the chromosome, allowing optimal compaction (about 1000-fold) to harmonize its replication, chromosome segregation and gene expression. This compaction is mediated both by the level of DNA supercoiling (Sc) and by association with nucleoid-binding proteins (NAPs). The level of Sc depends mainly on the enzymatic activities of their DNA topoisomerases, reaching a homeostatic equilibrium by the opposite activities of the topoisomerases that relax DNA (Topo I and Topo IV), and of gyrase, which introduces negative Sc. Our group has characterized the three Spn topoisomerases and two NAPs: HU and SatR. In addition, the availability of antimicrobials that inhibit each of the Spn topoisomerases has allowed us to analyze their transcriptome under conditions of local or global change of the Sc level and to define gene domains of coordinated transcription and similar functions. Fluoroquinolones, which inhibit Topo IV and gyrase, produce local changes in Sc that induce alterations in 6% of the transcriptome, altering metabolic pathways that originate an increase in reactive oxygen species (ROS) that contribute to lethality, in accordance with the general mechanism of bactericidal antibiotics. On the other hand, the induction of global changes in Sc by novobiocin (NOV, gyrase inhibitor), or by SCN (Topo I inhibitor), has allowed us to define topological domains. Global changes in Sc include the regulation of topoisomerase genes: its decrease activates the transcription of gyrase genes (gyrA, gyrB) and inhibits those of Topo IV (parEC) and Topo I (topA); the increase in Sc regulates the expression of topA. Decreased Sc affects 37% of the genome, with >68% of genes clustered in 15 domains. Increased Sc affects 10% of the genome, with 25% of the genes clustered in 12 domains. The AT content in the genome correlates with the domains, being higher in UP domains than in DOWN domains. The genes in the different domains have common functional characteristics, indicating that they have been subjected to topological selective pressure to determine the location of genes involved in metabolism, virulence and competition. 

The current objectives of the group are:
1.    Identification of factors that stabilize chromosome topology: NAPs, ncRNAs, intra-chromosomal interactions.
2.    Regulation of transcription in response to topological stress: in vivo localization of DNA topoisomerases, RNA polymerase and NAPs.
3.    Topo I as a new antimicrobial target and action of SCN. 
4.    Design of antisense RNAs and use of the CRISPR system as new antibacterial agents.

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Curso de Gestión de Calidad y Buenas Prácticas de Laboratorio. Ed. 3

Grammatico JP, Cuevas L (Edits.) y Grupo de expertos de la Organización Panamericana de la Salud OPS/OMS. Curso de Gestión de Calidad y Buenas Prácticas de Laboratorio. Ed. 3. OPS/OMS;. Washington, D.C., 2016. Disponible en: “http://iris.paho.org/xmlui/handle/123456789/31168”. ISBN: 978-92-75-11906-8

Gestión de la Calidad para laboratorios de ensayo. 1ª ed.

Grammatico JP, Cuevas L (Edits.). Gestión de la Calidad para laboratorios de ensayo. 1ª ed. Conicet-Madri+d; Buenos Aires, 2011. Disponible en: “http://www.madrimasd.org/Laboratorios/Documentos/Red-Laboratorios/documentos/Gest_Calidad_Ensayo.pdf”. ISBN: 978-950-692-095-1

Curso de Gestión de Calidad y Buenas Prácticas de Laboratorio.

Grupo de expertos de la Organización Panamericana de la Salud OPS/OMS. Curso de Gestión de Calidad y Buenas Prácticas de Laboratorio. OPS; Documentos Técnicos THR/HT 2009/001. Washington, D.C., 2009. ISBN: 978-92-75-32977-1

Guía Latinoamericana para la implementación de Código de Ética en los laboratorios de salud.

Grupo de expertos de la Organización Panamericana de la Salud (OPS/OMS). Guía Latinoamericana para la implementación de Código de Ética en los laboratorios de salud. Organización Panamericana de la Salud. Documentos Técnicos. Políticas y Regulación. THS/EV-2007/001; 2007. ISBN: 92-7-532702-5

Antiretroviral Therapy with Ritonavir-Boosted Atazanavir- and Lopinavir-Containing Regimens Correlates with Diminished HIV-1 Neutralization.

Yuste E, Gil H, García F and Sánchez-Merino V. Vaccines. 2024. 12:1176

PUBMED DOI

Identification of HIV-1 circulating BF1 recombinant form (CRF75_BF1) of Brazilian origin that also circulates in Southwestern Europe

Bacqué J, Delgado E, Gil H, Ibarra S, Benito S, García-Arata I, Moreno-Lorenzo M, Sáez de Arana E, Gómez-González C, Sánchez M, Montero V and Thomson MM. Front Microbiol. 2023. 14: 1301374

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Factors associated with HIV-1 resistance to integrase strand transfer inhibitors in Spain: Implications for dolutegravir-containing regimens.

Gil H, Delgado E, Benito S, Moreno-Lorenzo M, Thomson MM and Spanish Group for the study of antirretroviral drug Resistance. Front Microbiol. 2022. 13:1051096

PUBMED DOI

Transmission clusters, predominantly associated with men who have sex with men, play a main role in the propagation of HIV-1 in Northern Spain (2013-2018).

Gil H, Delgado E, Benito S, Georgalis L, Montero V, Sánchez M, Cañada-García JE, García-Bodas E, Diaz A, Thomson MM and Spanish group of the study of new HIV diagnoses. Front Microbiol. 2022. 13:782609

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Información adicional

• Taxonomic study. Objective: Association of already described species to new clinical processes. Description of new bacterial species. 

• Sensitivity studies against new antituberculous drugs: Objective: To evaluate the antimicrobial activity of new compounds for human use in clinical strains of Mycobacterium tuberculosis and in other species of non-tuberculous mycobacteria, for subsequent application in the treatment of these infections. 

• Molecular epidemiology of tuberculosis. Objectives: Molecular characterization of the members of the M. tuberculosis complex. Transmission studies with special surveillance of MDR/XDR tuberculosis. 

• Development of new methods of identification and detection of resistance in mycobacteria. Objectives: Optimization and development of molecular techniques for the diagnosis and detection of resistance.

Content with Investigacion Genética Bacteriana .