Term
| 5 keys to success for a pathogen |
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Definition
-ability to contact host cells
-ability to adhere to host cells and resist physical removal
-ability to invade host cells
-ability to complete for iron and other nutrients
-ability to resist immune defenses |
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Term
| ability to contact host cells |
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Definition
| -Helicobacter pylori swim with flagella thorugh mucous layer of stomach and adhere to epithelial cells of the mucous membranes |
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Term
| ability to adhere to host cells and resist physical removal |
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Definition
-pili (vibrio cholerae)
-adhesins (steptococcus pyogenes)
-capsules (streptococcus mutans) |
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Term
| ability to invade host cell |
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Definition
-invasins activate host cell's cytoskeletal machinery enabling bacterial entry into the cell by phagocytosis
-Shigella |
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Term
| ability to compete for iron and other nutrients |
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Definition
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Term
| ability to resist immune defense (phagocytosis and complement) |
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Definition
| -Streptococcus pneumonia is able to initially evade phagocytosis and cause infections such as pneumococcal pneumonia, sinusitis, otitis, and meningitis because of its capsule |
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Term
| Entry of microorganisms into the host |
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Definition
-mucous membranes
-skin
-parenteral route |
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Term
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Definition
-respiratory tract as airborne particles (water droplets)
-gastrointestinal tract (food, water, contaminated objects, fomites-esp. in nosocomial infections)
-genitourinary tract (sexual contact)
-conjunctiva (airborne particles, abrasion) |
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Term
| examples of microorganisms that enter resp., gastro, genital, conj. |
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Definition
-respiratory-Bordetella pertussis, influenza virus, Mycobacterium tuberculosis
-gastrointestinal- Vibrio cholerae, Mumps virus, Trichinella spiralis
-genital-N. gonorrhea, HIV-1, Treponema pallidum
-conjuctiva-Herpes simplex virus, staphlococcus, streptococcus |
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Term
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Definition
-insect/animal bites, wounds, injections
-Rickettsia rickettsii, Plasmodium, Rabies virus |
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Term
| entry thorough parenteral route |
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Definition
-tissue beneath skin or into mucous membranes
-insect/animal bites, wounds, intraveinous fluids, blood transfusions, catheterization
-HIV-1, HBV, Clostridium tetani |
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Term
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Definition
-attachment of microorganism to host cell mediated by adhesins
-results in the production of biofilms (dental plaque) |
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Term
| N. gonorrhea uses _____ to attach to ______ |
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Definition
-fimbraie
-receptors on cells of the genitourinary tract, eyes, and pharynx |
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Term
| Treponema pallidum uses _____ to attach to host cells |
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Definition
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Term
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Definition
-toxins
-capsules
-cell wall components
-enzymes |
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Term
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Definition
-proteins secreted from bacterial cell into surrounding environment
-very potent-small amount are necessary to cause
-solube-can diffuse into blood
-produced by G+ and G-
-very specific action on host
-converted into toxoids, can be used as vaccine |
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Term
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Definition
-A-B toxins
-membrane disrupting toxins
-superantigens |
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Term
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Definition
-most exoxins
-2 parts
-active component and binding component |
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Term
| Steps of exotoxin (Diptheria) |
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Definition
-bacterium produces and releases exotoxins
-B-component attaches to host cell receptor
-A-B exotoxin enters host by endocytosis
-A-B exotoxin enclosed in pinched off portion of plasma membrane of plasma membrane during pinocytosis
-A-B components seperate-A alters cell function by inhibiting protein synthesis. B is released |
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Term
| membrane disrupting toxins |
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Definition
-cause host cells to lyse by
-forming pores in plasma membrane (S. aureus)
-disrupting phospholipid portion (Clostridium perfringens)
-Hemolysin destroys RBCs
-Leokocidins kill phagocytic leukocytes |
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Term
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Definition
-non-specifically stimulate Th-cells to release large amount of cytokines
-results in fever, nausea, vomiting, diarrhea, shock and death |
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Term
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Definition
-part of G- cell wall (Lipid A)
-small amount escape into surrounding fluids when ingested by phagocytes
-stimulate macrophages to release high concentrations of cytokines
-more general effects on host (shock, fever, diarrhea) |
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Term
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Definition
-macrophage ingest G- bacteria
-it is degraded in a vacuole releasing endotoxins and stimulating release of cytokines
-cytokines are released into bloodstream by macrophages and travel to hypothalmus
-induces production of prostaglandins which cause fever |
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Term
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Definition
-polysaccharides or polypeptides found on surface of bacteria
-block attachment of phagocytic cells to bacteria
-inhibit phagocytosis
-Strep. pneumoniae, Haemophilus influenzae, Bacillus anthracis, Yersinia petsis |
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Term
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Definition
-strep. pyogenes produces M protein found on the cell surface and fimbriae
-enhances attachment to host epithelial cells and protects from phagocytosis |
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Term
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Definition
-coagulases
-kinases
-hyaluronidase
-collagenase
-IgA protease |
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Term
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Definition
-coagulate fibringoen present in blood
-fibrin clot may protect bacterium from phagocytosis
-Staphlococcus |
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Term
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Definition
-break down fibrin and digest blood clots formed by body to isolate infection
-s. pyogens
-s. aureus |
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Term
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Definition
-digests and damages connective tissues
-helps microorganism spread
-s. pyogenes
-c. perfringens |
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Term
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Definition
-breaks down collagen that forms connective tissues of organs, tissues, and muscle
-Clostridium |
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Term
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Definition
| -Neisseria produces this to destroy IgA (mucosal surfaces) |
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Term
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Definition
-class of proteins that rearrange actin filaments of host cytoskeleton
-enables penetration into the host cell
-Salmonella and E. coli |
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Term
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Definition
-proteins released into the medium and take the iron away from iron-transport proteins
-iron is a nutritional requirement for most pathogenic bacteria
-free iron is very scare in human body
-iron is mainly bound to hemoglobin, lactoferrin, transferrin, ferritin |
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Term
| pathogenic properties of viruses |
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Definition
-evasion of host immune defenses
-cytopathic effect |
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Term
| evasion of host immune defenses |
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Definition
| -viruses can grow inside host cells |
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Term
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Definition
-visible effects of viral infection
-may result in cell death (cytocidal)
-may damage without killing |
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Term
| cytopathic effect examples |
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Definition
-arrest of synthesis of macromolecules (HSV stops mitosis)
-release of cell's lysosomes contents
-formation of inclusion bodies (nuclear and/or cytoplasmic aggregates)
-formation of syncytium (fusion of adjacent infected cells)
-change in the host cell's function (measles virus makes host cell produce IL-12)
-production of interferons by infected cells
-induction of antigenic changes on host cell
-chromosomal changes in infected cell
-loss of contact inhibition (unregulated growth) |
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Term
| pathogenic properties of fungi |
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Definition
-toxins
-proteases
-capsules |
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Term
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Definition
-trichothecenes are fungal toxins that inhibit protein synthesis in eukaryotic cells (Fusarium and Stachybotrys)
-ergot is a toxin thats grows on grain (alkaloid that causes ergotism-hallucinations (LSD))
-also constricts capillaries and prevents proper blood circulation in limbs
-Aflatoxin is produced by Aspergillus flavins (grow on plants-peanuts)
-Mycotoxins-phalloidin and amanitin are produced by Amanita phalloides-neurotoxins |
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Term
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Definition
| -Candida albicans-produces a protease that modifies host cell membrane to allow its attachment |
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Term
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Definition
| -Crytococcus neoformans produces a capsule that protects it from phagcytosis |
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Term
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Definition
| invade and reproduce within host cells -lysis |
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Term
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Definition
| prevents normal acidification and digestion inside the phagocytic vacuoles of the macrophages it infects |
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Term
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Definition
| -attaches to the host cell and digests the cells and tissue fluids |
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Term
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Definition
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Term
| exit of microorganisms from host |
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Definition
-resp tract- talking, breathing, singing, shouting, coughing, sneezing
-dead cells from skin
-feces and urine
-blood
-milk
-secretions from vagina and penis |
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