Introduction Bacterial virulence intrinsic characteristics that influence the bacterium’s ability to infect a host endotoxins are a type of bacterial virulence factor Endotoxins a lipopolysaccharide found in the cell walls of gram-negative organisms heat-stable release into the body via cell lysis or detachment from the bacteria not actively secreted (unlike exotoxins) bacterial lysis due to antibiotic treatment can cause a large release of endotoxins components O antigen core polysaccharide lipid A causes shock, sepsis, DIC, and death effects from lipid A component macrophage activation release of IL-1 and IL-6 fever release of TNF-alpha fever and hypotension release of nitric oxide hypotension complement activation C3a histamine release, causing hypotension and edema C5a neutrophil chemotaxis tissue factor activation activates coagulation cascade results in disseminated intravascular coagulation Exotoxins vs Endotoxins Exotoxin Endotoxin Species that produce the toxin Some species of gram-positive and gram-negative organisms Gram-negative organisms Listeria Method of release Actively secreted Bacterial cell lysis or fragmentation Gene location Plasmid or bacteriophage Bacterial chromosome Toxicity level High toxicity Low toxicity Vaccines Available for some toxins in the form of toxoids No vaccines available Properties Heat-labile Heat-stable Examples Vibrio cholera Diphtheria Salmonella Shigella Clostridium tetani Clostridium botulinum Neisseria meningitidis Escherichia coli Pseudomonas