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76 Cards in this Set
- Front
- Back
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Why developed countries have fewer infections than underdeveloped
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1. Clean water
2. Proper Sanitation 3. Proper handling and storage of food 4. Reduction in overcrowded living conditions |
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Disease
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infection that produces recognizable signs or symptoms
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Colonization
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Pathogenic and non pathogenic organisms that establish themselves at sites in the body. Gr+ on skin, throat, nasal, intestines.
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Asymptomatic Carriage
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a person infected with pathogenic microbes with no visible signs or symptoms.
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Virulence/Pathogenicity
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disease causing ability of a microbe
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Virulence factors
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Microbial product or strategy used by microbes to infect and cause disease and illness.
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What are the 2 types of virulence factors?
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1. Promotes colonization/invasion
2. Cause host cell damage |
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Describe why virulence factors promote colonization/invasion
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1. Only in GNB, attach to host cell surface molecule. Will target host cell glycoprotein and glycolipid.
2. Gr+ and Gr-, invasion of bacterial cell binds to integrins (host cell proteins) inducing intestinal cells to be phagocytic. |
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Describe how virulence factors cause host cell damage
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1. Fimbrial adhesions - proteins that cause closer attachment to glycolipid and
protein. 2. Immune response inhibitors 3. Toxins 4. Formation of biofilm – secreted by basal layer to surface of anything; not responsive to antibiotics 5. Motility and chemotaxis – move toward/away from chem. substance. 6. Iron acquiring mechanism – sideophore binds to iron and internalized for growth |
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What does F protein do?
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- Protein F attaches to fibronectin and binds to human host cell
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What are invasins?
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proteins produced by bacterial cells that promote bacterial penetration into mammalian cells.
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What is a capsule and what does it do?
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having a capsule can prevent a cell from being phagocytized. Mediate specific or non specific adherence of bacteria to particular surfaces. The also protect bacteria from engulfment by predatory phagocytes and from attack by antimicrobial agents.
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What are Exotoxins?
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toxins secreted into external environment that cause host cell damage.
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What are the 3 types of Exotoxins and what do they do?
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1. A-B Binding Toxin – enzymatic active toxic portion; on surface B attaches to A and
internalizes and toxicizes. 2. Membrane Disrupting – a. non-enzymatic proteins that poke holes into target host cell plasma membrane (i.e. S. aureus) b. Phospholipidase poke holes through phospholipid layer (i.e. Clostridium) 3. Superantigens – whole bacterial cells, fungal cells, algal cells, protozoa, viral partc., etc. that cause massive inflammative immune response. Stimulate 1 in 4 T helper cells. |
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What are Endotoxins?
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– toxins embedded in bacteria and released when bacterial cells lyse that cause host cell damage. Gr- bacteria (lipid, surface, porine proteins).
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Antigens
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chemical substance that will stimulate and provoke an immune response.
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What are examples of antigens?
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Exotoxins, B venom, milk proteins, viral capsids, etc.
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Non specific constituitive defense
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those defenses against pathogens, etc. that are not specific to each pathogen, including things like physical barriers, chemical barriers, some cellular defenses, inflammation, fever and molecular defenses.
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Lysozyme
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Small enzyme that attacks the protective cell wall of bacteria. Protects us from the ever present danager of bacterial infection.
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Lactoferrin
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An iron binding protein found in neutrophils and bodily secretions (milk, tears, saliva) having bactericidal activity and acting as an inhibitor of colony formation by granulocytes and macrophage.
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Lactoperoxidase
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found in milk and reacts with certain chemicals to generate antibacterial compounds.
Part of body's immune system and helps protect senstive areas from colonization by bacteria |
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Why is Lactoperoxidase important in babies?
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In breast milk and protects their intestinal tract from bacterial attack.
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What are PMN's and what do they do?
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PMN's are polymorphonuclear because nucleus changes shape.
Most abundant type of WBC, highly phagocytic. |
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What are monocytes and what do they do?
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WBCs that are not actively phagocytic until maturity.
During infection mature into macrophage. |
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What are macrophage and what do they do?
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play a significant role in immunity by producing cytokines and stimulating antibody production of T cells.
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What is Serum Complement and how is it activated?
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A series of multi protein complex components 1-9 that attract WBC to infection site.
Activated by classical and alternative pathways. |
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What are classical pathways?
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traditional antigen/antibody binding via bacterial flagella or cell wall.
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What are alternative pathways?
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microbial fragments and sometimes wholecells
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Antibodies
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Proteins that exist in bodily fluids and are used both as a detection and response device by the immune system.
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Where are antibodies made?
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made in plasma cells, which are a type of WBC and are part of body's natural defense system.
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What are the types of Anitbodies and what do they do?
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IgM - macroglobulin, largest antibody and are the 1st in circulation after stimulating the B cells. Good at activating serum complement but not at killing.
IgG, gamma, appear 48-72 hours after B cell stimulation and good at killing microbes and neutralizing viral capsids and toxins that have yet toi enter the cell SIgA - found in mucus, breast milk, saliva, good at binding to antigen and not good at killing. IgE - sensitizes human cells to certain antigens during allergic reaction, provokes histamine response. IgD - functions as surface receptor protein on B cells before attacking antigen. |
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What factors affect immune system?
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age, stress, diet, gender
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What are fungi?
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Arose 250 million years ago, ubiquitos, natures recycler, life would cease without as it impacts CO2.
Produce cellulase to degrade cellulose. |
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Name 4 clinical fungal infections and what they do
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1. Cutaneous - attacks skin, hair, but not tissue. Ex. Tineapedius
2. Subcutaneous - affects tissue just under the skin, but not invasive. Ex. Sporotroichosis 3. Systemic Fungi - invade lungs and other body organs. Ex. Cryptococcus neoformans 4. Opportunistic Fungi - non pathogenic, but can become pathogenic in immunocomprimised. Ex. histoplasmosis |
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How are fungal infections acquired?
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1. contaminated plant material
2. via soil 3. accidentally inhaling fungal spores |
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Reasons why fungal infections are increasing?
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1. increase in incidence of HIV/AIDS
2. increase in use of immuno suppressed agents given during solid organ transplants |
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What are yeast?
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unicellular, creamy, opaque. Canidida albican pathogenic yeast.
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What are molds?
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multicellular, cottony, woody, and form long hyphae. Have genetically identical nuceli
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What are hyphae?
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fine, branching tubes which make up the body of fungus.
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What is myceilum?
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Mass of hypahe that constitutes the vegatative part of a fungus.
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What are parasites?
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microbes that benefit while harming the host. Includes viruses, protistan, algae.
Ex. Lyme disease, Hep B, AIDS |
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What 3 groups of organisms are studied in parasitology?
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1. Protozoan - single celled, eukaryotic motile organisms that subsist on other organism's food.
2. Helmintes - multi cellular worms that include flat worms (fluke and tape) and round worms (hook or whip) 3. Arthropods - jointed appendages with exoskeleton or chitin. |
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What is a host?
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An organism that harbors and nourishes another organism.
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What are the different types of hosts?
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1. Definitive - a host in which a parasite develops to an adult or sexually mature stage.
2. Intermediate - a host in which a parasite passes on or more of its asexual stages; usually designated first and second. 3. Reservoir - an animal that is infected by a parasite and which serves as a source of infection for humans or another species. |
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What is a vector?
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an arthropod responsible for transmission of infection.
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What is the adult stage of a parasite?
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sexual maturity
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What is the larval stage of a parasite?
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sexual immaturity
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What are diagnostic techniques for detecting a parasite?
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Wet Mount - suspend fresh stool in sterile phys. saline and observe under low/high dry power.
Fecal Concentration - suspend stool in formaline ethyl acetate to break up fibers and concentrate protozoan cyst. Antigen detection kits - detect antibody to parasitic antigen |
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Name the 6 types of disease transmission
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1. Vertical Direct - passed from mother to offspring through uterus during delivery, colstrium milk or latent virus in germ cells Ex. syphillus, HIV
2. Horizontal Direct - disease spread from person to person during sex, nasal secretions or sneeze/cough. Ex. formite surface, food, water. 3. Horizontal Indirect - disease spread through environment. Formite surface or mosquito. Ex. skin colonization 4. Commensalism - microbe benefits but host is not harmed 5. Symbiosis - both microbe and human host benefit. Ex. lactobacilli 6. Opportunistic - one's own endogenous. E. coli, fine on own but once accesses circulatory system then harmful. |
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Nosocomial Infections
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an infection for which there was not evidence of it existing or incubating prior to 72 hours before admission.
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What is the most common Nosocomial Infection?
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Candida albicans
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What are the risk factors for Nosocomial infections
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1. Underlying medical conditions
2. Majority of hospital patients are undergoing invasive procedure 3. Many hospital patients are immunocomprimised or suppressed and are at risk for infection or one that can be opportunistic. 4. Hospital environments foster and exert selective pressure for more highly resistant microbes |
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What are the top 5 organisms identified with Nosocomial infections?
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1. E. coli
2. Staph aeurus 3. Enterococcus - E. faecalis & faecim 4. P. aeurgonosa 5. Coag. neg. Staph epidermidis |
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Sites of Nosocomial Infections
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1. BSI - Blood Stream Infections
2. Respiratory Nosocomial Infections - #1 killer because of pneumonia. 20-50% fatality rate. 3. Prothetis Nosocomial Infection - exposed implants 4. UTI - Urinary Catheter Infections - E. coli |
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What are viruses?
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obligate intracellular parasites between 20 and 200 nanometers.
Always parasitic and need host cell to replicate Can't synth. protein or generate energy |
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How are viruses classified?
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1. genus and species
2. have envelope or not 3. chemical make up of DNA 4. Capsid symmetry 5. Viral replication strategy |
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What are the different types of human viral morphology?
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1. Icosahedral Capsid Symmetry - 20 sided soccer ball w/ capsomere, nucleo capsid, very rigid
Ex. Hep A, Polio, Adenol 2. Icosohedral Capsid Symmetry w/ enevlope - envelope, peoplomer, matrix proteins Ex. Hep B, Herpes, Rubella |
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What are the different types of human viral morphology?
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3. Helical Virus w/ envelope - spiral capsomere around genome, flexible
Ex. Ebola, Mumps, Measles 4. Complex Virus w/ envelope - Core membrane Ex. Pox virus |
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Capsid
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the shell of protein that protects the nucleic acid of a virus; composed of structural units or capsomeres.
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Nucelocapsid
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The basic structure of a virus consisting of core of nucelic acid enclosed in a protein
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Viral genome
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has DNA or RNA but never both; genome must contain information encoded in a form which can be recognized and decoded by the particular type of cell parasitized.
Contains single or dbl strand, linear/circular or segmented, viron, capsid and viral envelope |
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What are the 6 steps in viral replication?
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1. Attachment - adsorption
virus must have attachment sites that protein recognize and bind to host cell receptor sites 2. Penetration - occurs if no enevelope, susceptible host cell will phag. and internalize. If enevelope will fuse with plasma membrane 3. Uncoating - Viral capsid has to be enzymatically degraded so genome can be release into host cell. 4. Synthesis - synth. of mRNA 5. Subunit assembly - assemb le into capids, but only 20% contain enough viral genome. 6. Release - released by budding or rupture of infected cell. Endo retic. or nucleus host cell memebrane lyse. |
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What 3 important overlapping events must take place in synthesis in viral replication?
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1. Viral specific mRNA is synthesized
2. Viral genome synthesized 3. Viral mRNA translated |
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What is Cytocidal and Non-Cytocidal?
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Cytocidal - damage to infected host cells caused by infecting viruses which cause cell to die.
Non-Cytocidal - damage to infected host cell cuased by infecting viruses that does not cause cell to die. |
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What are Cytopathic effects?
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consequences of the viruses metabolic needs and those of the host cell simply not corresponding.
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What are the 4 group of RNA Viruses?
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1. Negative Strand RNA - genome consists of one or more single stranded antisense RNA. Makes copies with RNA replicase to serve as mRNAs.
2. Positive Strand RNA - genome is a molecule of single stranded sense RNA. Sense RNA encodes RNA replicase. 3. Genome w/ several molecules of dbl stranded RNA- transcribes dbl stranded RNA into mRNA and exports into cytosol of infected cell. 4. Retroviruses - contain a reverse transcriptase that copies their RNA genome into DNA. |
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Reverse Transcriptase
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copy the viral RNA genome into DNA prior to its integration into host cells. Transcribes single strand RNA into single strand DNA. Once inside the cell, takes over DNA.
Viruses containing this enzyme are called retroviruses. |
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What is TB and what is its cause?
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Mycobacterium Tuberculosis
obligate aerobe that causes serious diseases but not contagious unless active. Due transmitted by close contact. 20% adult mortality rate. |
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What is Lyme Disease and what is its cause?
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Bordella burgdorfy
caused by deer ticks. Spirochete, long, slender and motile. 3 stages; 1) red bullseye, 2) flu symptoms and neurological symptoms, 3) disabling, fatigue, paralysis, dementia and death |
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What is Legionnaires Disease and what causes it?
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Legionella pneumonphila
Legionella bacteria survive in soil and water, but rarely cause infections. Indoors, though, Legionella bacteria can multiply in all kinds of water systems. Parasite is protozoa. Survives phag., neutorphils, monocytes and macrophage. |
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What is C. Difficle and was causes it? (also called pseudo membranous colitis)
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infection of the colon caused by clostridium difficle.
Characterized by offensive diarreha, fever and abdominal pain. Can develop toxic megacolon. Antibiotic associate diarreha. |
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What is Toxic Shock Syndrome and what causes it?
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potentially fatal illness caused by bacterial toxins including Staph auerus and Strep pyrogenes.
Assoc. with superabsobent tampons. |
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What is meningitis and what causes it?
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inflammation of the membrane covering the brain and spinal cord due to virus bacteria.
Group B strep in babies, nisseria meningitis in older |
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What is Food Posioning and what causes it?
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any illness resulting from consumption of contaminated food, pathogenic bacteria, viruses or parasites in contaminated food rather than chemical or natural toxins.
Common by Campylobacter jejuni, samonella and e. coli |
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What is Samonellosis and what causes it?
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caused due to uncooked meat and affects intestinal tract.
Salmonella bacteria typically live in animal and human intestines and are shared through feces. Humans become infected most frequently through contaminated water or food sources. |
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What is Shigellosis and what causes it?
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Known as bacillary disentery in most severe form, foodborne illness caused by bacteria shigella.
Can be caused by direct contact with bacteria in stool or can be passed in contaminated food or by drinking or swimming in contaminated water. |
