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63 Cards in this Set
- Front
- Back
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colonization |
-formation of a population of microorganisms in the host that does not cause disease -begins in the birth canal & continues throughout life |
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What area's of the body are normally sterile? |
-womb -stomach -lower respiratory tract: trachea, lungs, bronchi -kidney, bladder, fallopian tube |
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what area's of the body should be colonized with bacteria? |
1.mode of birth: vagina/ c-section (c-section exposed to more microbes 2. feeding environments: formula & breast fed -breast feeding gives a variety of microbes=quick adaption immune system 3.environment:P how clean the living area is & exposure to bacteria |
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why is colonization important to overall health? |
-extremely important for development of healthy immune system - re colonization occurs after antibiotic use
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probiotics |
-nutritional supplements -not regulated by the FDA -are living organisms with a protective coating -coating must be strong enough to get through HCL |
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Normal flora |
-organisms present in absence of disease -symbiotic |
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benefits of normal flora |
-immune system development -provides host with nutrients -prevents colonization with pathogens |
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pathogenic bacteria |
-reside on a host but dont cause symptoms |
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major genus of bacteria found on skin: |
-candida spp. -staphylococcus spp. -clostridium spp. -propionbacterium (cause of acne) |
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major genus of bacteria found in mouth: |
-streptococcus -bacterial plaques (slime layer) form dental plaque, can lead to cavities/tartar build up -Anaerobes |
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major genus of bacteria in the upper respiratory tract: |
-colonized by streptococci -opportunistic pathogens (S.aureus)~found 30% -nasopharynx: haemophilus influenza, streptococcus pneumonia |
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major genus of bacteria in the lower respiratory tract: |
-trachea, bronchi, & lungs -normally sterile |
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major genus of bacteria in the gastrointestinal tract: |
-stomach: heliobacter, spores, parasites -colon: obligate anaerobes, facultative anaerobes, commensals, lactobacilli -small intestine: few bacteria
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major genus of bacteria in the genitourinary: |
-kidney, bladder, fallopian tubes: sterile -women: child bearing years- lactobacilli -pre puberty/ post menopause: year, gram neg, gram pos cocci |
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commensals |
-bacteria in colon -like to promote health -healthy digestion -provide nutrients |
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Transit Flora |
-unable to colonize because of normal flora -easily eliminated by immune system |
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Symbiosis |
-host & microbe benefit |
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commensalism |
-host is not harmed & does not benefit, the microbe benefits |
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parasitism |
-host is damaged while microbe benefits |
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what are the host defense mechanisms used against pathogenic microbes? |
-physical barriers -innate immunity -adaptive immunity |
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Physical barriers |
-first line of defense -barriers: skin, mucous membranes, enzymes, normal flora |
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skin as a barrier |
-keratinized -desquamation: shedding of outer most layer -normal flora competed for nutrients -lysozyme present in sweat |
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Mucosal cells |
-part of the epithelial lining -ciliated: sweeps away germs |
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Goblet cells |
-part of epithelial lining -secrets mucous -traps bacteria before it reaches outer surface of cells -lubricates cells to prevent damage & may promote microbial invasion -contains antibodies
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Mucosa-associated lymphoid tissue (MALT) |
-part of the immune system -resides below epithelium |
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what antimicrobial substance is secreted by the eyes: |
-tears -lysozyme & IgA |
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what antimicrobial substance is secreted by the mucous membranes: |
-mucous & other secretions -IgA, IgG causes opsonization ( changed so more easily & readily engulfed by phagocytes & macrophages) |
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what antimicrobial substance is secreted by the respiratory tract: |
-cilia transport away from the lung |
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what antimicrobial substance is secreted by the GI tract: |
-acidic pH (1.0) -normal flora of colon -MALT |
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what antimicrobial substance is secreted by the GU: |
-acidic pH (4.0-5.0) |
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Beta-lysins |
-secreted by platelets -bacterial cytol for gram positive bacteria |
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lactoferrin |
-produced by activated neutrophiles -during inflammation it affects gram pos & neg -binds to free iron (necessary for microbial growth) |
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Innate Immunity |
-not specific -no stimulation needed -genetics= germ line -immediate response -specifically targets conserved microbial structures: LPS, mannose, N-formly methionly -non-clonal |
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non-clonal |
-identical receptors on all cells of same lineage |
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adaptive immunity |
-very specific -requires stimulation by antigen presenting cells -genetics=somatic recombination (very diverse) -delayed response -antibody response: targets pathogens specifically -clonal
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clonal |
clones of lymphocytes with distinct set recptors |
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Innate Immune Defense |
- Toll like receptors (TLR): flagellin, LPS -cell receptors for mannose -macorphages -granulocytes -activation for compliment cascade -inflammation |
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macrophages |
-phagocytosis -destroy bacteria with lysozyme |
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granulocytes |
-toxic granules -example: neutrophiles-inhibit bacteria cell growth |
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Adaptive Immune Defense |
-humoral response -primary & secondary response - IgG, IgA, IgM |
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humoral response |
-production of antibodies -binds to pathogen & helps innate immune system find the pathogen -increases phagocytosis -increases destruction by compliment |
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IgG |
-circulates in blood |
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IgA |
-secretory -tears, saliva |
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IgM |
-"first responder" - made by B cells -very large |
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cell-mediated response |
-part of adaptive immune system -T cells differentiate & can express diff mcls -recruits the innate immune system to specific area to get the bacteria causing the response -can be toxic causing organ failure (shock) |
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airborne transmission |
-respiratory secretions aerosolized by coughing, sneezing, talking -must be resistant to drying & inactivation UV light |
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transmission food & water |
-gastrointestinal infections: ingesting bacteria that produce toxins inside host or ingesting preformed toxins |
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close contact |
-passage organisms: salivary, skin, genital contact -hand to hand, hand to face |
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cuts & bites |
-rabies or pasteurella spp. (cat bite) |
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arthropod vector |
bite of a tick, flea, mite, louse |
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zoonoses |
-wild animal contact |
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pathogen |
-organism "recognized to cause disease in a healthy immunocompetent individual" -person has fully functioning immune system |
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susceptibility factors for disease: |
-age -underlying disease -poor nutrition -pregnancy -genetic factors -any organism under the right conditions can cause disease, even normal flora
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opportunistic pathogen |
-do not usually cause disease but able to cause disease under specific conditions |
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Iatrogenic infection |
-condition actually caused by a medical intervention |
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Virulence factor |
-helps pathogen multiply with body & help it cause disease |
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Virulence |
-the ability to cause disease & the degree of pathology -ability to prevent phagocytosis -cell adhesion -survive intracellular -produce extracellular toxins |
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Superantigen |
-are mitogens : activate T cells directly -example: streptococci -cause T cells to release tumor necrosis factor -inflammatory mediators produced & released UNREGULATED -mlcs cause severe damage, toxic shock syndrome |
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what are the tactics microbes use to evade an immune system? |
-adhesion -endotoxins -exotoxins -(avoid) host immune system |
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adhesion |
-virulence factor: colonizes the host -cell surface structures that mediate attachment -target & bind specific receptors on cells -bacteria adhere to host with fimbria & capsules
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Endotoxins |
-part of the bacterial cell membrane -LPS of gram neg bacteria - ability to activate T cells without macrophage -upregulate all elements of immune system -causes toxic shock (activation of compliment cascade/ inflammation) |
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Exotoxins |
-excreted by bacteria -only organisms with extra cellular DNA (phage, plasmid) -made by both gram pos & neg -form dimers with A &B subunits -B bind to specific cell surface receptors -A taken into cell where damage occurs |
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(avoid) host immune system |
-secrete or place on cell surface: toxins, immune, modulators -change cell surface antigens -survive inside infected cell (avoid lysozyme) -inhibit compliment activation of activity of TLR -inhibit chemkines, cytokines & interferons |
