Investigation Of The Growth And Survival Of Staphylococcus Aureus In Cftr-Deficient Macrophages, Bita Azad

Electronic Thesis and Dissertation Repository

Staphylococcus aureus and its small colony variants (SCVs) are commonly isolated from the lungs of cystic fibrosis (CF) patients. Although studies have suggested that cystic fibrosis transmembrane regulator (CFTR)-deficient macrophages are diminished in their ability to kill intracellular pathogens, whether this is true for CFTR-deficient macrophages infected with S. aureus or its SCVs is unknown. I employed gentamicin protection and eFluorÔ-670-based proliferation assays to assess the intracellular replication of S. aureus in CFTR inhibitor treated THP-1 and primary human macrophages, and in primary macrophages derived from CF patient blood. My work shows that the susceptibility of CFTR-deficient macrophages to the …

Granulocyte Colony-Stimulating Factor: Its Role In Gut-Homing Macrophage Generation And Colitis, And Production By Probiotics, Shahab Meshkibaf

Electronic Thesis and Dissertation Repository

The pleiotropic cytokine granulocyte-colony stimulatory factor (G-CSF) is mainly required for the generation of neutrophils, but its role in macrophage generation has also been reported. In addition, G-CSF is effective for the down-regulation of inflammatory cytokines and ameliorating gut disorders, such as colitis. However, the G-CSF function in macrophage generation and gut immunity remains unclear. The first focus of this thesis was to assess the role of G-CSF in macrophage generation and its contribution to gut immunity. G-CSF was found to promote the generation of Gr-1high/F4/80+ macrophages in macrophage (M)-CSF-treated bone marrow cells, most likely through suppressing cell death. Gr-1high …

Hcpe, A Potential Immuno-Modulatory Protein From Helicobacter Pylori That Is Dependent On The Disulfide Bond Protein Dsbhp, Jeff Lester

Electronic Thesis and Dissertation Repository

H. pylori is a human gastric pathogen that colonizes ~ 50% of the world’s population. It can cause gastritis, gastric or duodenal ulcers and also gastric cancer. H. pylori produces Helicobacter cysteine rich protein HcpE, a secreted protein which may play a role in virulence. In this study we show that HcpE is secreted in the culture supernatant both as a soluble protein and in association with outer membrane vesicles, and may play a role in the modulation of H. pylori inflammatory responses. We identified that Dsb_HP is necessary for HcpE production and secretion in H. pylori, and …

The Role Of Superantigens During Staphylococcus Aureus Nasal Colonization And Infection, Stacey Xu

Electronic Thesis and Dissertation Repository

Superantigens (SAgs) are potent toxins produced by bacteria such as Staphylococcus aureus that function to overactivate T cells resulting in massive cytokine production and immune activation. Despite decades of research on the structure and function of these proteins, as well as their role in severe diseases such as toxic shock syndrome, the question as to why strains of S. aureus produce SAgs and the role that they play in the life cycle of these bacteria remains unanswered. The contribution of SAgs towards pathogenicity and bacterial survival in vivo were assessed using isogenic SAg deletion knockouts in conjunction with SAg-sensitive humanized …

Sub-Inhibitory Antibiotics Enhance Virulence, Persistence, And Pathogenesis Of Uropathogens, Lee W. Goneau

Electronic Thesis and Dissertation Repository

In addition to their bactericidal effects, antibiotics are potent signal mediators at sub-inhibitory levels in the environment. The ability to modulate community structure in this niche raises concerns over their capacity to influence pathogenesis in patients during antibiotic therapy. This concept forms the basis of this thesis, and is explored using models of prophylactic therapy for recurrent urinary tract infection (UTI) management.

Sub-inhibitory ciprofloxacin, ampicillin, and gentamicin were found to augment virulence in vitro, increasing adherence and urothelial cell invasion in uropathogenic Escherichia coli (UPEC) and Staphylococcus saprophyticus. In addition, biofilm formation was increased, and swarming motility decreased. …

Characterization Of Staphylococcus Aureus Lipase, Vithooshan Vijayakumaran

Electronic Thesis and Dissertation Repository

USA300, a strain of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA), has become prevalent in the community. Colonization of human skin requires mechanisms that allow this bacterium to overcome the innate immune defenses on the skin, including secretion of antimicrobial lipids. Antimicrobial lipids inhibit S. aureus growth and induce the staphylococcal proteolytic cascade, producing aureolysin (Aur) which processes the lipase glycerol ester hydrolase (Geh). Nearly all S. aureus strains secrete Geh, yet little information exists concerning its function. Using purified Aur and Geh we confirm that aureolysin processes proGeh to Geh. We then confirmed that geh was required for lipase activity …