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| | =[[Bacteria - WikiBlood|Bacteria]]= | | =[[Bacteria - WikiBlood|Bacteria]]= |
| − | [[Image:Bacterial structure.png|thumb|right|150px|Bacteria Structure - Wikimedia Commons 2008]]
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| − | ==Structure==
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| − | Bacteria offer the immune system a greater range of foreign components with which to be recognized, including:
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| − | *Flagellum
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| − | *Pili
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| − | *Capsule
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| − | *Cellular components: membrane, cell sap containing enzymes, genetic material, cell wall
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| − | ==Pathogenesis==
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| − | Bacterial invasion can be either:
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| − | *'''Localized''', such as an '''abscess'''
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| − | *'''Systemic''', such as '''septicemia'''
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| − | Some bacteria also produce toxins:
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| − | *'''Endotoxogenic''': cell wall degradation products (lipopolysaccharide) released into the blood stream, causing toxic shock
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| − | *'''Exotoxogenic''': bacteria produce and secrete toxin (such as tetanus and botulism)
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| − | ==Replication==
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| − | The lifespan of bacteria differs from that of viruses in that it includes a '''colonization''' phase, which occurs on epithelial surfaces. As bacteria are capable of self-replication (i.e. they don't require host cellular machinery), this colonization phase allows them to develop a highly skilled and lethal army before invading the body. Once invasion occurs, spread can occur via the vascular or lymphatic systems. The pathogenesis of a particular strain of bacteria very much depends upon its location in the body: "''Streptococcus pneumoniae'' in the lung causes pneumonia...whereas in the blood it causes a rapidly fatal systemic illness, pneumoncoccal sepsis." (Murphy, et al, 43)
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| − | ==Immunity to Bacteria==
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| − | *Bacterial evasion of immunity
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| − | **Bacterial capsules can avoid phagocytosis and complement activation
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| − | **Some bacteria are able to survive phagocytosis and evade digestion (such as mycobacterium and ''Leptospira'')
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| − |
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| − | *[[Innate Immune System - WikiBlood#Innate Immunity to Bacteria|Innate Immunity to Bacteria]]
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| − | *Adaptive Immunity to Bacteria:
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| − | Phagocytosis and digestion are the primary tools of the Immune System to conquering bacterial infection. These are enhanced by the production of [[Immunoglobulin G - WikiBlood|IgG]] and CD8+ Tcells, as well as by [[Complement - WikiBlood|complement]] activation.
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| − | ==Prevention and control==
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| − | '''Antibiotics''' can be used to prevent and control bacterial invasion, replication, and dissemination.
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| | =[[Parasites - WikiBlood|Parasites]]= | | =[[Parasites - WikiBlood|Parasites]]= |