IMED1004 Lecture Notes - Lecture 7: Cholera Toxin, Gram-Negative Bacteria, Mucous Membrane
17 Sep 2018
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Document Summary
Nature of infectious diseases ii: host damage & innate immune. Response: bacterial pathogens can cause disease in several ways = toxins, enzyme production, quorum sensing a 2 way relationship. Bacteria virulence sometimes regulated by quorum sensing and biofilm production. Bacteria do not express certain genes until the number of cells present is sufficient to pass threshold for infection. Aggregated bacterial assemblies within host that enhance ability to capture ability to capture and retain nutrients; impede uptake of antibiotics and disinfectants; inhibit phagocytosis. How a bacterium interferes with normal host functions and/or causes tissue damage is species dependent. Some pathogenic bacteria produce toxins = poisons that alter normal metabolic functions of host cells. Toxins= virulence factors= features of microorganisms that contribute to pathogenesis. Interfere with host cellular process in number of ways: vary in specificity- some act on certain cell types difference in symptoms means difference in cell type targets, bacterium may secrete one or more types of exotoxins.
