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Mycobacteria

Líneas de investigación

Content with Investigacion Genética Bacteriana .

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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Characterisation of Legionella Clinical Isolates in Spain from 2012 to 2022

González-Rubio, J.M.; Cascajero, A.; Baladrón, B.; González-Camacho, F. Microorganisms 2024, 12, 1253

PUBMED DOI

Programa de Legionelosis. En Echevarría Mayo JE y Oteo Iglesias J (Editores) Programas de Vigilancia Microbiológica Centro Nacional de Microbiología.

Fernando González-Camacho y Almudena Cascajero. Programa de Legionelosis. En Echevarría Mayo JE y Oteo Iglesias J (Editores) Programas de Vigilancia Microbiológica Centro Nacional de Microbiología. Volumen 2:77-89. 2021-2022 Majadahonda (Madrid); Instituto de Salud Carlos III, Centro Nacional de Microbiología: 2023.

Chikungunya virus infections among travellers returning to Spain, 2008 to 2014

3. Maria Dolores Fernandez Garcia; Mathieu Bangert; Fernando de Ory; Arantxa Potente; Lourdes Hernandez; Fatima Lasala; Laura Herrero; Francisca Molero; Anabel Negredo; Ana Vázquez; Teodora Minguito; Pilar Balfagón; Jesus de la Fuente; Sabino Puente; Eva Ramírez de Arellano; Mar Lago; Miguel Martinez; Joaquim Gascón; Francesca Norman; Rogelio Lopez Velez; Elena Sulleiro; Diana Pou; Nuria Serre; Ricardo Fernández Roblas; Antonio Tenorio; Leticia Franco; Maria Paz Sanchez Seco. Chikungunya virus infections among travellers returning to Spain, 2008 to 2014. Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin. 21 - 36, (Sweden): 08/09/2016. ISSN 1560-7917

PUBMED DOI

Legionella feeleii: Ubiquitous Pathogen in the Environment and Causative Agent of Pneumonia

Vaccaro L, Gomes TS, Izquierdo F, Magnet A, Llorens Berzosa S, Ollero D, Salso S, Alhambra A, Gómez C, López Cano M, Pelaz C, Bellido Samaniego B, Del Aguila C, Fenoy S, Hurtado-Marcos C. Front Microbiol. 2021;12:707187.

DOI

Immunogenicity of a third dose with mRNA-vaccines in the ChAdOx1-S/BNT162b2 vaccination regimen against SARS-CoV-2 variants.

García-Pérez J, Borobia AM, Pérez-Olmeda M, Portolés A, Castaño L, Campins-Artí M, Bertrán MJ, Bermejo M, Arribas JR, López A, Ascaso-Del-Rio A, Arana-Arri E, Fuentes Camps I, Vilella A, Cascajero A, García-Morales MT, Castillo de la Osa M, Pérez Ingidua C, Lora D, Jiménez-Santana P, Pino-Rosa S, Gómez de la Cámara A, De La Torre-Tarazona E, Calonge E, Cruces R, Belda-Iniesta C, Alcamí J, Frías J, Carcas AJ, Díez-Fuertes F. iScience. 2024; 27(9):110728

PUBMED DOI

Longer intervals between SARS-CoV-2 infection and mRNA-1273 doses improve the neutralization of different variants of concern

García-Pérez J, Bermejo M, Ramírez-García A, De La Torre-Tarazona HE, Cascajero A, Castillo de la Osa M, Jiménez P, Aparicio Gómez M, Calonge E, Sancho-López A, Payares-Herrera C, Layunta Acero R, Vicente-Izquierdo L, Avendaño-Solá C, Alcamí J, Pérez-Olmeda M, Díez-Fuertes F. J Med Virol. 2023; 95(3):e28679

PUBMED DOI

Maca (Lepidium meyenii Walp.) inhibits HIV-1 infection through the activity of thiadiazole alkaloids in viral integration.

Apaza-Ticona L, Beltrán M, Moraga E, Cossio D, Bermejo P, Guerra JA, Alcamí J, Bedoya LM. J Ethnopharmacol. 2024; 335:118613

PUBMED DOI

Immune response and reactogenicity after immunization with two-doses of an experimental COVID-19 vaccine (CVnCOV) followed by a third-fourth shot with a standard mRNA vaccine (BNT162b2): RescueVacs multicenter cohort study

Ascaso-Del-Rio A, García-Pérez J, Pérez-Olmeda M, Arana-Arri E, Vergara I, Pérez-Ingidua C, Bermejo M, Castillo de la Osa M, Imaz-Ayo N, Riaño Fernández I, Astasio González O, Díez-Fuertes F, Meijide S, Arrizabalaga J, Hernández Gutiérrez L, de la Torre-Tarazona HE, Mariano Lázaro A, Vargas-Castrillón E, Alcamí J, Portolés A; RescueVac study Group. EClinicalMedicine. 2022; 51:101542

PUBMED DOI

Content with Investigacion Genética Bacteriana .

List of staff

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 .