Title Promoter Affiliations Abstract "Identification of novel surface-expressed factors mediating virulence and biofilm formation in methicillin-resistant Staphylococcus aureus" "Herman Goossens, Jean-Pierre Hernalsteens" "University of Antwerp, Department of Bio-engineering Sciences, Biology" "Methicilline-resistant Staphylococcus aureus (MRSA) recently became of the leading causes of hospital-acquired infections (HA) and infections that are acquired in the Community (CA). HA-MRSA and CA-MRSA show major differences in the distribution of toxin and antibiotic resistance genes. The worldwide spread of some HA-MRSA clones may be associated with an increased expression of virulence genes in these bacteria. In addition to a more aggressive virulence, also a different survival strategy is used by these bacteria that in vivo produce biofilms contributing to the long-term persistence of infections. The biofilm environment provides not only more resistance to the few antibiotics that are still active against MRSA in planktonic form, but also induces a modified growth, metabolic activity and gene expression in comparison with their planktonic counterparts. The latest molecular techniques and animal models of infection will be used to investigate the differences in the formation of biofilms between HA and CA-MRSA and to study their content and expression of virulence genes. In addition, the (virulence) mechanisms which are at the basis of the success of the dominant HA-MRSA clones will be studied. The presence of new virulence factors which are brought to the expression to the surface of MRSA and could be involved in bio-film formation and in host recognition will also be examined. These studies will contribute to a better understanding of the pathogenic mechanisms used by MRSA causing recalcitrant infections and in the development of more targeted therapies for MRSA infections." "Structural biology of Helicobacter pylori virulence factors" "Han Remaut" "Department of Bio-engineering Sciences" "Helicobacter pylori is a widespread human pathogen that is the leading cause of chronic gastritis and is associated with the development of peptic ulcers and gastric cancer. Current medical guidelines advocate Helicobacter eradication therapy in peptic ulcer disease, low-grade gastric MALT lymphoma and after gastric cancer resection. Because Helicobacter pylori is one of the most significant risk factors for gastric cancer, H. pylori eradication has been proposed as a possible primary chemo-preventive strategy to reduce gastric cancer incidence. However, the alarming increase of antibiotic resistance in H. pylori strains has serious implications for current and future antibiotic-based therapies. In addition, only 10-20% of Helicobacter infections will ever progress into clinical disease. A mounting body of evidence indicates disease outcome is highly strain specific and is a function of a limited number of virulence factors. We will set up a structural biology program of Helicobacter virulence factors for the design of novel, virulence-targeted antibiotics and as an aid for epitope selection in vaccine development programs. Bacterial adherence is a major factor in Helicobacter virulence and its extraordinary longevity of infection. Two major Helicobacter - host interactions are formed between the blood group antigen-binding adhesin BabA and the fucosylated Lewis B and ABO blood group antigens present on gastric epithelial cells and between the sialic acid-binding adhesin SabA and the sialyl-Lewis x/a antigens present on inflamed gastric tissue, erythrocytes and infiltrated neutrophils. A chemical library of pharmacophore-like compounds will be screened for BabA or SabA adhesion inhibitors. The structural characterization of BabA and SabA in complex with their respective glycan receptors by X-ray crystallography will be followed by the structure-guided lead optimization and receptor-based virtual screening of BabA and SabA inhibitors." "Identification of novel surface-expressed factors mediating virulence and biofilm formation in methicillin-resistant Staphylococcus aureus." "Vaccine & Infectious Disease Institute (VAXINFECTIO)" "A first objective of the project is the identification of genes encoding novel virulence factors, which are expressed at the bacterial surface of MRSA.A second objective is to study the differences in biofilm-forming capabilities between hospital-acquired (HA) and community-acquired (CA)-MRSA in the presence and absence of antibiotic pressure.A third objective of this project is to find an explanation why certain MRSA clones are highly epidemic." "Virulence factors of Bacillus cereus and host-pathogen interactions" "Department of Food Technology, Safety and Health" "Bacillus cereus is one of the key toxigenic foodborne pathogens of concern to modern food industry, especially for a group of refrigerated foods of extended durability and dry foods. This species comprises a highly versatile, psychrotrophic and mesophilic, and incredibly armored group of opportunistic pathogenic bacteria, which directly in the food or once ingested by the human host may secrete a wide array of harmful toxins and Ultimately, the emetic food poisoning is caused by the emetic toxin, known as cereulide (Cer), which is produced during the growth of emetic B. cereus in food, whereas diarrheal food poisoning is the result of enterotoxin production by viable vegetative B. cereus cells in the small intestine. B. cereus enterotoxins comprise hemolysin BL (Hbl), Non-hemolytic enterotoxin (Nhe), and cytotoxin K (CytK1 and CytK2) as tree major toxins. The overall aim of this project is to provide understanding of the host-pathogen cross talk in the specific case of B. cereus by examining simultaneously functional and metabolic changes in human host cells, and link this ‘funtionomic” data with the transcriptomes of the infected human cells. In parallel expression of selected virulence factors in diarrheal and emetic type of B. cereus will be assessed. The parallel measurements in eukaryotic and bacterial cells during the simulated infection will be performed as a need to better understand the virulence mechanism and pathogenic potential of B. cereus." "Helicobacter suis virulence factors associated with cytotoxicity, inhibition of T-cell proliferation and gastric pathology" "The role of H. suis gamma-glutamyl transpeptidase in gastric epithelial cell death, inhibition of T-cell proliferation and induction of gastric pathology will be studied. Other virulence mechanisms involved in death of host cells will also be identified." "The role of bacterial biofilms as a major cause of therapeutic failure in intensive care units (ICU): an in vitro and in vivo study of 'biofilm' virulence factors." "Vaccine & Infectious Disease Institute (VAXINFECTIO), Proteinchemistry, proteomics and epigenetic signalling(PPES), Laboratory for Microbiology, Parasitology and Hygiene (LMPH)" "Bacterial isolates from intensive care unit patients will be collected from urinary and intravascular catheters and endotracheal tubes. The biofilm phenotype in relation to antibiotic treatment failure will be investigated using molecular biological, bio-imaging techniques and in vitro and in vivo biofilm models. Particular emphasis will be given to Escherichia coli for urinary tract infections (UTI), Pseudomonas aeruginosa for ventilation associated pneumonia (VAP) and Staphylococcus aureus for systemic infections related to venous catheters. The acquired library of fully typed strains will enable in depth study of putative virulence factorsthat contribute to biofilm formation and treatment failure." "Role of bacterial biofilms as a cause of therapeutic failure in intensive care units: in vitro and in vivo study of 'biofilms' virulence factors." "Laboratory for Microbiology, Parasitology and Hygiene (LMPH)" "This project represents a research agreement between the UA and on the onther hand IWT. UA provides IWT research results mentioned in the title of the project under the conditions as stipulated in this contract." "Virulence factors of Aspergillus fumigatus involved in interactions with avian macrophages" "An Martel" "Department of Pathobiology, Pharmacology and Zoological Medicine" "ASpergillosis is one of the most common infectious diseases that causes dead in birds. In this studies the interactions between Aspergillus fumigatus and avian macrophages will bes tudied an the genes involved will be identified. In a final study the role of these virulence genes in vivo will be assessed." "Study of endocytosis, transcytosis and nuclear location of porcine lactoferrin in enteroids and design of smart lactoferrin by nanobody mediated targeting of lactoferrin to intestinal Chlamydia suis and its virulence factors" "Daisy Vanrompay" "Department of Translational Physiology, Infectiology and Public Health, Department of Animal Sciences and Aquatic Ecology" "Chlamydia suis is a gram negative obligate intracellular bacterium. C. suis is an emerging pig pathogen causing significant economic losses in the pork industry. The focus of our proposal is on prevention of intestinal C. suis in swine as: i) the gut functions as a C. suis reservoir, ii) C. suis and especially tetracycline resistant C. suis, causes economic loss and preventive strategies are currently unavailable and iii) C. suis is a zoonotic pathogen. We hypothesize that porcine LF (pLF), a protein of the innate immune system, might prevent C. suis intestinal infection through its antibacterial and immunomodulatory capacity. To support our hypothesis, we will first study receptor-mediated endocytosis and biodistribution of pLF inside porcine enteroids as well as the signaling pathways triggered by pLF in enteroids. We strongly believe that the antibacterial capacity of pLF can even be increased by nanobody-mediated targeting of pLF towards the outer membrane of chlamydia or its Type 3 Secretion System (T3SS). Nanobodies are single-domain antibody fragments originating from the variable part of the heavy chain of camelid heavy chain antibodies. Nanobodies against the chlamydia outer membrane and against components of the T3SS will be coupled to pLF and used against C. suis infections in porcine enteroids. In the end, we will study the effect of these ‘smart’ pLFs on intestinal C. suis infection during small intestinal segment perfusion (SISP) experiments in SPF pigs." "A combined structure-activity and biophysical investigation of the cyclic lipopeptide tolaasin, the virulence factor causing brown blotch disease" "Annemieke Madder" "Department of Organic and Macromolecular Chemistry" "Tolaasin, an 18 residue cyclic lipopeptide, is the main virulence factor of Pseudomonas tolaasii, and causes brown blotch disease in edible mushrooms. In addition to this antifungal activity, this secondary metabolite also display activity against Gram-positive, Gram-negative bacteria and cytotoxicity against MDA-MB-231 cancer cells. This wide targeting of cells is attributed to its membrane-lytic properties. While experimental data supports direct interaction with cellular membranes, molecular level understanding of the features of tolaasin involved and the underlying mechanisms ultimately leading to cell lysis are not well understood. In this project, a total synthesis route for tolaasin will be developed, followed by combined and comparative biological and biophysical evaluation of a series of specifically designed analogues. Of note, monitoring of leakage events and kinetics using ps-time-resolved fluorescence spectroscopy will provide unprecedented insight in the nature of tolaasin induced membrane perturbation, thus providing fundamental, molecular level understanding of the underlying mode of action."