Project

Back to overview

Studying Staphylococcus aureus pathogenic determinants by trans- fer and expression in less virulent bacteria. Molecular analysis and relevance in the model of experimental endocarditis in vivo.

Applicant Moreillon Philippe
Number 65371
Funding scheme Project funding
Research institution Service de Médecine Interne Département de Médecine CHUV
Institution of higher education University of Lausanne - LA
Main discipline Clinical Cardiovascular Research
Start/End 01.10.2001 - 30.09.2006
Approved amount 844'605.00
Show all

All Disciplines (2)

Discipline
Clinical Cardiovascular Research
Clinical Pathophysiology

Keywords (10)

STAPHYLOCOCCUS AUREUS; PATHOGENIC DETERMINANTS; TRANSFER AND EXPRESSION; LESS VIRULENT BACTERIA; MOLECULAR ANALYSIS; RELEVANCE; MODEL OF EXPERIMENTAL; ENDOCARDITIS IN VIVO; GLOBAL REGULATORS; ADOPTIVE PATHOGENESIS

Lay Summary (English)

Lead
Lay summary
This report covers the second and last year of a 2-years prolongation of grant # 3200 065371.01 on the pathogenesis of Staphylococcus aureus in experimental endocarditis. Four goals were pursued. First, 17 of the 21 S.aureus LPXTG wall-associated adhesins were expressed in lactococci and tested for their ability to promote in vitro adherence and invasion into cultured cell lines, and in vivo infection in experimental endocarditis.
The results showed that fibrinogen-binding protein A (ClfA) and fibronectin-binding protein A (FnBPA) were the most active adhesin of the17 tested species, identifying these two proteins as the main staphylococcal determinants for endovascular infection. The other 15 proteins were either inactive or marginally active (e.g. SdrD and Pls) in the experimental settings. Therefore, the main efforts to block staphylococcal adhesins in prophylaxis or therapy should be aimed at ClfA and/or FnBPA. Second, new Mass Spectrometry (MS)-based proteomic strategies were developed to identify and quantify bacterial surface proteins present in tissue samples. These are invaluable tools to investigate the physiology of bacterial pathogens in situ. Third, we succeeded in synthesizing a very large peptide fragment (of ca. 100 aminoacids) capable of interfering with the activity of FnBPA in vitro. This will allow further determination of the minimal FnBPA region(s) involved in fibrinogen- and fibronectin-binding. Fourth, we completed the construction of lactococcal recombinants expressing several staphylococcal adhesins in tandem (e.g. various combinations of collagen-binding protein (Cna), plasmin-sensitive protein (Pls) and various truncated forms of FnBPA), thus allowing additional studies on protein collaboration in the infection process. The experimental work complies with the originally proposed program, and the results provide both a definitive understanding of the major S. aureus determinants implicated in endocarditis pathogenesis, and new tools to investigate the function and expression of bacterial proteins during in vivo infection.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Associated projects

Number Title Start Funding scheme
100667 Problems of detection and treatment of glycopeptide Intermediate Staphylococcus aureus (GISA) Infections:Solving the issue using Experimental Endocarditis 01.04.2003 Project funding
113854 Pathogenesis of Staphylococcus aureus Experimental Infection: Diversity and Function of Virulence Genes in Bacterial Isolates form human and Animal Origin 01.01.2007 Project funding
47099 Importance of small-colony variants of Staphylococcus aureus and of bacterial surface adhesins in pathogenesis of experimental endocarditis. 01.10.1996 Project funding
143650 New Insights into Mechanisms of Human-Bovine Host Jump of Staphylococcus aureus Clonal Cluster CC8 01.11.2012 Project funding

-