Mechanism of especially bacterial pathogenesis that is associated, for example, with , , and various infections.
Key to infectious disease, particularly by bacteria, that involves tissue invasion but no toxin production is a lack of exotoxins rather than necessarily a lack of endotoxins.
Thus, the associated with a number of pathogens are not so much exotoxins that directly damage body tissues as factors that allow tissue invasion, , and .
In many cases, these organisms avoid control by surviving and replicating within – i.e., intracellular parasitism – as following phagocytosis. In the process of invasion, however, can occur, and sufficient organism numbers therefore can result in significant .
M. tuberculosis, for example, employs various virulence factors that allow it to evade host . This is followed by induction of a (type IV) hypersensitivity reaction. Additional body damage results from M. tuberculosis-induced of body macrophages, the release of enzymes and other substances which has the effect of killing body cells and otherwise damaging surrounding tissues (i.e., as resulting in ), all without production or release of exotoxins from the bacterium.
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As with M. tuberculosis, the pathogenesis of Y. pestis also is associated with immune-system evasion, bacterial infection of macrophages, pathogenic immune responses, and , which for Y. pestis and associated is seen largely in the lymph nodes. Unlike M. tuberculosis, however, Y. pestis is a Gram-negative organism and thus additional pathogenesis is associated with endotoxin release and associated septic shock as well as .
It is inflammation in response to Salmonella infections that results in fluid loss and resulting . As with infection by Y. pestis, Salmonella also is a Gram-negative bacterium, and pathology results from endotoxin release into host tissues, particularly following bacterial . The location of pathology follows bacterial dissemination about the body, with localized inflammation associated with foci of infection. Given sufficient dissemination along with resulting high levels of endotoxin then septic shock can result. As with M. tuberculosis and Y. pestis, Salmonella too displays .