Pediatric Research and Clinical Center for Infectious Diseases
Department of medical microbiology and molecular epidemiology
Irina Tsvetkova is a researcher at the Pediatric Research and Clinical Center for Infectious Diseases, Department of Medical microbiology and molecular epidemiology (Saint-Petersburg, Russian Federation). Irina graduated from Pirogov Russian National Research Medical University, Faculty of Biomedicine, in 2001. Irina defended her PhD thesis on "Genotypic characteristics of Streptococcus pneumoniae belonging to epidemic genetic lines (circulating in Russia)" in December 2021. Projects with Irina's contribution: Tsvetkova I.A. et al. Mechanisms of virulence regulation and global distribution of vaccine candidate antigens in the high virulent Streptococcus pneumoniae strains. // 12th International Symposium on Pneumococci and Pneumococcal Diseases (ISPPD-12), 2020. URL: https://cslide.ctimeetingtech.com/isppd20/attendee/eposter/poster/654 (article in progress). S. Sidorenko et al. Multicenter study of serotype distribution of Streptococcus pneumoniae nasopharyngeal isolates from healthy children in the Russian Federation after introduction of PCV13 into the National Vaccination Calendar. // Diagnostic Microbiology and Infectious Disease. 2020. Muraviov A.A. et al. The prevalence of circulating S. pneumoniae serotypes in people older than 18 years: healthy carriers, patients with acute otitis media, community-acquired pneumonia, and invasive pneumococcal infections (epidemiological study «SPECTRUM»). // Clinical Microbiology and Antimicrobial Chemotherapy. 2019. Tsvetkova I.A. et al. Clonality of Streptococcus pneumoniae isolates in Russia, circulating from 1980 to 2017. //Antibiotics and Chemotherapy. 2019.

Presenter Of 1 Presentation

O025 - MECHANISMS OF VIRULENCE REGULATION AND GLOBAL DISTRIBUTION OF VACCINE CANDIDATE ANTIGENS IN THE HIGH VIRULENT STREPTOCOCCUS PNEUMONIAE STRAINS (ID 285)

Session Type
Parallel Session
Date
Mon, 20.06.2022
Session Time
15:20 - 16:35
Room
Birchwood Ballroom
Lecture Time
16:05 - 16:15

Abstract

Background

Metabolic flexibility is a prerequisite for successful transition of Streptococcus pneumoniae (Spn) from colonizing to invasive state. The aim of this study was to investigate the common metabolic features of pneumococcus invasive strains and propose vaccine candidate antigens.

Methods

The dataset (1058 PubMLST Spn strains) was stratified by genotype and included all known epidemically significant invasive and non-invasive clones. Genomes (495) were analyzed with GenomeComparator. Core gene variant matrix was used to run machine learning algorithms (RandomForest, XGBoost) to find gene variants associations with genotypes and invasiveness. Topology and composition of phylogenetic trees clusters comparison was performed using Visual TreeCmp.

Results

Phylogenetic analysis (based on MLST concatenates) revealed clustering of global pneumococcal population into the three groups (A, B1, B2), which may be associated with virulence. 181 genes were significant for the formation of A/B1/B2 groups: the components of various metabolic pathways (fatty acid biosynthesis, phenylalanine, biotin, arginine, galactose, fructose, mannose, purine bases, pyruvate, cysteine and methionine, alanine, aspartate and glutamate) and different virulence factors. Invasiveness is regulated by network of interacting genes variants: strH (exo-β-D-N-acetylglucosaminidase), carbohydrate metabolism components (gnd, dexB), aromatic amino acid synthesis pathways (aroE), relA regulatory gene (GTP pyrophosphokinase), peptidoglycan synthesis and cell division genes (murD, pbp1A), regulatory genes of polysaccharide capsule expression (wzg-wzh-wze).

Conclusions

Carbohydrates and aromatic amino acids metabolism pathways are involved in the regulation of cellular processes and phenotypic features of pneumococcus, including virulence. We achieved the list of vaccine candidates, which must be confirmed by reverse vaccinology.

Hide