Uporaba proteomskih in aptamernih pristopov za študij interakcij gostitelj-mikroorganizem pri stafilokoknih in klostridijskih okužbah (Slovene)

Clostridium difficile and Staphylococcus aureus, both important pathogens causing significant burden in health care system, will be used as model organisms to study microbial factors that might be associated with increased virulence. Different approaches will be used to define differences between clinical isolates with higher and lower virulence, defined as S. aureus causing endocarditis-associated vs. bacteremia and C. difficile causing diarrhoea vs. colitis or pseudomembranous colitis. Comparative analysis of secreted factors and bacterial cell wall bound fractions in each bacterial species grown under different conditions will be assessed by mass spectrometry-based proteomic approaches. NMR will be used as a complementary technique to study the possible differences in selected virulence factors due to posttranslational modifications. Aptamers are in vitro engineered nucleic acids selected from complex libraries of synthetic nucleic acid by an iterative process called SELEX. They can be generated against functional groups, small molecules (e.g. amino acids, proteins) and even whole organisms (e.g. bacterial cell). Development of aptamer-based assay for detection of differences between strains associated with mild or severe disease will be another approach used in this project.

The results contributed to understanding of virulence potential of two important human pathogens, C. difficile and S. aureus in terms of properties important for endemicity, colonization and development of disease symptoms. We have shown that subinhibitory concentrations of antimicrobials could affect some of these properties. Additionally, the project has contributed to development of approaches for detection of C. difficile spores by specific aptamers.

In this project three Centres of Excellence and SME have participated and this has enabled complementation in knowledge and technology and establishment or development of different scientific areas at national level. Also several early researchers were included in the project. Some of the developed methodologies and obtained results (aptamers) have potential for use in development of diagnostic approaches. Project consortium members were presenting the results at national and international scientific meetings and workshops.