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Bacterial Genetics

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.

Proyectos de investigación

Content with Investigacion Genética Bacteriana .

1) Project Title: Interaction Between DNA Supercoiling and Transcription in the Human Pathogen  Streptococcus pneumoniae

Principal Investigator:   Adela González de la Campa  
Funding Entity:   Ministry of Science and Innovation, State Research Agency (Call for "R&D&I Projects" 2020 – "Research Challenges" and "Knowledge Generation" Modalities).  
Reference:   PID2021-124738OB-100.  
Duration:   2022-2025.  
Funding Amount:   €108,900.
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2) Project Title:   Study of the Factors Organizing the Chromosome of  Streptococcus pneumoniae: New Antibiotic Targets and Resistance Mechanisms.

Principal Investigator:   Adela González de la Campa  
Funding Entity:   Ministry of Economy, Industry, and Competitiveness. State Research Agency.  
Reference:   BIO2017-82951-R.  
Duration:   2018-2020.  
Funding Amount:   €169,400.  

3) Project Title:   Role of DNA Topoisomerases and Nucleoid-Associated Proteins in the Chromosome Organization of  Streptococcus pneumoniae: Response to Antibiotics and Virulence.  

Principal Investigator:   Adela González de la Campa  
Funding Entity:   Ministry of Economy and Competitiveness. Secretariat of State for Research, Development, and Innovation.  
Reference:   BIO2014-55462.  
Duration:   2015-2017.  
Funding Amount:   €193,600.  

4) Project Title:   The Control of Supercoiling Level in  Streptococcus pneumoniae  as an Antimicrobial Target.  

Principal Investigator:   Adela González de la Campa  
Funding Entity:   Ministry of Economy and Competitiveness. Secretariat of State for Research, Development, and Innovation.  
Reference:   BIO2011-25343.  
Duration:   2012-2015.  
Funding Amount:   €209,000.  

5) Project Title:   Role of Small Non-Coding RNAs in the Pathogenicity of  Streptococcus pneumoniae.   

Principal Investigator:   Mónica Amblar Esteban  
Funding Entity:   Ministry of Economy and Competitiveness. Strategic Health Action (AES).  
Reference:   PI11/00656.  
Duration:   2012-2015.  
Funding Amount:   €198,714.
 

Publicaciones destacadas

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The Diagnostic Laboratory Hub: A New Health Care System Reveals the Incidence and Mortality of Tuberculosis, Histoplasmosis, and Cryptococcosis of PWH in Guatemala. Open Forum Infect Dis. 2019 Dec

Samayoa B, Aguirre L, Bonilla O, Medina N, Lau-Bonilla D, Mercado D, Moller A, Perez JC, Alastruey-Izquierdo A, Arathoon E, Denning DW, Rodríguez-Tudela JL; “Fungired”. The Diagnostic Laboratory Hub: A New Health Care System Reveals the Incidence and Mortality of Tuberculosis, Histoplasmosis, and Cryptococcosis of PWH in Guatemala. Open Forum Infect Dis. 2019 Dec 15;7(1):ofz534. doi: 10.1093/ofid/ofz534. PMID: 31915715.

PUBMED DOI

Fungired. Comparative performance of the laboratory assays used by a Diagnostic Laboratory Hub for opportunistic infections in people living with HIV. AIDS. 2020 Sep 1

Medina N, Alastruey-Izquierdo A, Mercado D, Bonilla O, Pérez JC, Aguirre L, Samayoa B, Arathoon E, Denning DW, Rodriguez-Tudela JL; Fungired. Comparative performance of the laboratory assays used by a Diagnostic Laboratory Hub for opportunistic infections in people living with HIV. AIDS. 2020 Sep 1;34(11):1625-1632. doi: 10.1097/QAD.0000000000002631. PMID: 32694415.

PUBMED DOI

Population-Based Program of filamentous fungi and Antifungal Resistance in Spain (FILPOP STUDY). Antimicrob Agents Chemother. 2013 Jul

Ana Alastruey-Izquierdo*, Emilia Mellado, Teresa Pelaez, Javier Pemán, Soledad Zapico, María Álvarez, Juan L Rodriguez-Tudela, Manuel Cuenca-Estrella Population-Based Program of filamentous fungi and Antifungal Resistance in Spain (FILPOP STUDY). Antimicrob Agents Chemother. 2013 Jul;57(7):3380-7. doi: 10.1128/AAC.01287-13. PMID: 28319466

PUBMED DOI

The global problem of antifungal resistance: prevalence, mechanisms, and management. Lancet Infect Dis. 2017 Dec

Perlin DS, Rautemaa-Richardson R, Alastruey-Izquierdo A. The global problem of antifungal resistance: prevalence, mechanisms, and management. Lancet Infect Dis. 2017 Dec;17(12. doi: 10.1016/S1473-3099(17)30316-X. PMID: 28774698.

PUBMED DOI

Project from GEMICOMED (SEIMC) and REIPI. Molecular identification and susceptibility testing of molds isolated in a Prospective Surveillance of Triazole Resistance in Spain (FILPOP2 study). Antimicrob Agents Chemother. 2018 Jun

Alastruey-Izquierdo A*, Alcazar-Fuoli L, Rivero-Menéndez O, Ayats J, Castro C, García-Rodríguez J, Goterris-Bonet L, Ibáñez-Martínez E, Linares-Sicilia MJ, Martin-Gomez MT, Martín-Mazuelos E, Pelaez T, Peman J, Rezusta A, Rojo S, Tejero R, Vicente Anza D, Viñuelas J, Zapico MS, Cuenca-Estrella M; members of the FILPOP2 Project from GEMICOMED (SEIMC) and REIPI. Molecular identification and susceptibility testing of molds isolated in a Prospective Surveillance of Triazole Resistance in Spain (FILPOP2 study). Antimicrob Agents Chemother. 2018 Jun 25. doi: 10.1128/AAC.00358-18. PMID: 29941643.

PUBMED DOI

In vitro activity of APX001A against rare moulds using EUCAST and CLSI methodologies. J Antimicrob Chemother. 2019 May 1

Rivero-Menendez O, Cuenca-Estrella M, Alastruey-Izquierdo A.* In vitro activity of APX001A against rare moulds using EUCAST and CLSI methodologies. J Antimicrob Chemother. 2019 May 1;74(5):1295-1299. doi: 10.1093/jac/dkz022. PMID: 30753499.

PUBMED DOI

In vitro activity of olorofim (F901318) against clinical isolates of cryptic species of Aspergillus by EUCAST and CLSI methodologies. J Antimicrob Chemother. 2019 Jun 1

Rivero-Menendez O, Cuenca-Estrella M, Alastruey-Izquierdo A.* In vitro activity of olorofim (F901318) against clinical isolates of cryptic species of Aspergillus by EUCAST and CLSI methodologies. J Antimicrob Chemother. 2019 Jun 1;74(6):1586-1590. doi: 10.1093/jac/dkz078. PMID: 30891600.

PUBMED DOI

Molecular Identification, Antifungal Susceptibility Testing, and Mechanisms of Azole Resistance in Aspergillus Species Received within a Surveillance Program on Antifungal Resistance in Spain. Antimicrob Agents Chemother. 2019 Aug 23

Rivero-Menendez O, Soto-Debran JC, Medina N, Lucio J, Mellado E, Alastruey-Izquierdo A*. Molecular Identification, Antifungal Susceptibility Testing, and Mechanisms of Azole Resistance in Aspergillus Species Received within a Surveillance Program on Antifungal Resistance in Spain. Antimicrob Agents Chemother. 2019 Aug 23;63(9). doi: 10.1128/AAC.00865-19. PMID: 31285229.

PUBMED DOI

Content with Investigacion Genética Bacteriana .

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Información adicional

Streptococcus pneumoniae is a human pathogen that, despite the development of vaccines, continues to be an important cause of mortality and morbidity. We investigate the mechanisms of antibiotic resistance in this bacterium. On the one hand by identifying new therapeutic targets and on the other hand by investigating the molecular basis of the action of antibiotics already used in clinical practice (the fluoroquinolones levofloxacin and moxifloxacin) or not yet used (seconeolitsine). For this purpose, we used a multidisciplinary analysis involving genomics, transcriptomics and proteomics to understand the organization of the S. pneumoniae chromosome and the identification of the factors that stabilize this organization, including ncRNAs. Changes in the level of global supercoiling, either by inhibition of gyrase (decrease) or by inhibition of topoisomerase I (increase) alter the transcriptome. The modulated genes are located in domains, whose genes show specific functional characteristics. The aim is to identify new factors essential for S. pneumoniae physiology and to characterize transcriptional regulation in response to topological stress. In addition, RNA interference technology and CRISPR systems will be used as novel antibacterials. These studies will establish the bases for translational research aimed at the development of new therapeutic targets for the treatment of pneumococcal diseases.

Streptococcus pneumoniae is a human pathogen that, despite the development of vaccines, continues to be an important cause of mortality and morbidity. We investigate the mechanisms of antibiotic resistance in this bacterium. On the one hand by identifying new therapeutic targets and on the other hand by investigating the molecular basis of the action of antibiotics already used in clinical practice (the fluoroquinolones levofloxacin and moxifloxacin) or not yet used (seconeolitsine). For this purpose, we used a multidisciplinary analysis involving genomics, transcriptomics and proteomics to understand the organization of the S. pneumoniae chromosome and the identification of the factors that stabilize this organization, including ncRNAs. Changes in the level of global supercoiling, either by inhibition of gyrase (decrease) or by inhibition of topoisomerase I (increase) alter the transcriptome. The modulated genes are located in domains, whose genes show specific functional characteristics. The aim is to identify new factors essential for S. pneumoniae physiology and to characterize transcriptional regulation in response to topological stress. In addition, RNA interference technology and CRISPR systems will be used as novel antibacterials. These studies will establish the bases for translational research aimed at the development of new therapeutic targets for the treatment of pneumococcal diseases.

Content with Investigacion Genética Bacteriana .

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