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59 Cards in this Set
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Pathogenicity |
- Ability to cause disease by overcoming host defenses - To cause disease, must gain access to the host, adhere to host tissues, penetrate of evade host defenses and damage host tissues |
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Virulence |
- Term referring to the degree of pathogenicity |
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- Mucous membranes (Respiratory, GI and genitourinary tracts, conjunctiva) - Skin - Parenteral Route (Bites, wounds) MSP |
3 Types of Portals of Entry for Pathogens |
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ID50 |
- Measures virulence of a microbe - Infectious dose for 50% of sample population - Lower numbers means easier to acquire Ex: Bacillus anthracis and endospores - Skin < Inhalation < Ingestion |
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LD50 |
- Measures potency of a toxin - Lethal dose for 50% of a sample population - Lower numbers means easier to cause symptoms |
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Adherence |
- Usually necessary process of attachment of pathogens to host tissues by the use of ligands to host cell receptors |
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Adhesins Glycocalyx, Fimbriae |
- Ligands on the pathogen that bind to host cell receptors (typically mannose sugar) - Made of glycoproteins or lipoproteins - Name 2 Examples |
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Biofilms |
- Formation of microbial communities that share nutrients Ex: Dental plaque, swimming pool wall algae, shower door scum |
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Capsules |
- Glycocalyx layer around cell wall - Impairs phagocytosis, increases virulence Ex: Streptococcus pneumoniae and Haemophilus influenzae |
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Streptococcus pneumoniae Haemophilus influenzae HIM - SP |
- Name 2 Types of Bacteria that cause pneumonia and/or meningitis; Aided by its capsule |
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- M Protein - Opa protein - Waxy lipid (mycolic acid) |
3 Components of the Pathogen's Cell Wall that aids in Penetration of Host Defenses |
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M Protein Streptococcus pyogenes MSP |
- Cell wall component that helps pathogen in resisting phagocytosis because it is heat and acid resistant Give example of bacteria that utilizes this |
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Opa protein Neisseria gonorrhoeae ONG |
- Cell wall component that helps pathogen attach to host cells - This component is also capable of antigenic variation Give example of bacteria that utilizes this |
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Waxy Lipid (Mycolic Acid) Mycobacterium tuberculosis MT |
- Cell wall component that helps pathogen resist digestion by phagocytes, can even be facultative intracellular phagocyte reproductive Give example of bacteria that utilizes this |
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Coagulases: Coagulate fibrinogen Kinases: Digest fibrin clots Collagenase: Collagen break down KCC |
Name 3 Types of Enzymes that aids pathogens in penetrating host defenses and what they do |
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Antigenic Variation |
- Term referring to when pathogens alter their surface antigens, rendering antibodies ineffective - Thus, by the time body mounts an adaptive immune response, pathogen is unaffected |
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Invasins |
- Surface proteins produced by bacteria that rearrange nearby actin filaments of the cytoskeleton, thus aiding in penetration of the host cell cytoskeleton |
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Salmonella typhimurium STECI |
Name 1 example of bacteria that uses invasins to "ruffle" host cell's plasma membrane, aiding in penetration |
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Shigella Listeria ASL |
Name 2 Genuses of Bacteria that uses actin filaments of the host cell's cytoskeleton to move from one cell to the next, after penetration |
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Iron |
- Key nutrient that is required for most pathogenic bacteria within the host - Siderophores are proteins secreted by pathogens that bind to this nutrient more tightly than host cells |
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Siderophores |
- Proteins secreted by pathogens that bind iron more tightly than host cells |
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- Disrupts function - Uses nutrients - Produces waste products - Multiplies causing rupture DNWM |
4 Steps of Direct Damage to Host Cell |
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Lysogenic Conversion |
- Term referring to when characteristics of a microbe are changed due to incorporation of a prophage Ex: E. coli strain |
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- Toxins - Antibiotic Production - Enzymes TEA |
Name 3 things plasmids may carry genes for |
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Toxins |
- Poisonous substances produced by microorganisms - Primary factor contributing to pathogenic properties - May produce fever, cardiovascular problems, diarrhea and/or shock |
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Toxigenicity |
Term referring to the ability of a microorganism to produce a toxin |
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Toxemia |
- Term referring to the presence of toxin in the host's blood |
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Intoxications |
- Term referring to the presence of toxin; there is no microbial growth |
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Exotoxins |
- Toxic Proteins produced inside pathogenic bacteria (More commonly Gram +) as part of their growth and metabolism - Then secreted out to surrounding medium during 'log phase' following cell lysis - Soluble in body fluids; destroy host cells and inhibit metabolic functions - Highly specific Ex: A-B, Membrane-disrupting, Superantigens |
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Antitoxins |
- Term referring to antibodies against specific exotoxins - Can be produced even if exotoxins are inactivated by heat or mordant chemicals (iodine) |
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Toxoids Diphtheria Tetanus DT |
- Term referring to inactivated exotoxins (typically by heat or mordants such as iodine) used in vaccines - Stimulates antitoxin production so immunity is produced - Name two genuses of bacterium that can be prevented by this vaccination |
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Clostridium botulinum CBX |
- Example of a gram positive bacterium that produces exotoxins |
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- Active Enzyme Component - Binding Component Diphtheria toxin |
Which component of the A-B exotoxin is the A Part? B Part? Give an example of this toxin: |
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1. B Part 2. Receptor-mediated endocytosis 3. Inhibiting protein synthesis 4. Released from host cell 5. Reused by plasma membrane |
1. Which part of the A-B toxin binds to the host cell receptor?
2. The exotoxin enters the cell by which process? 3. A-B part separates, A component alters host cell function how? 4. What happens to the B component? 5. What happens to the receptor on the B component? |
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Membrane-Disrupting Toxins |
- Exotoxins that lyse host cells by disrupting plasma membranes - Contribute to virulence by killing host cells such as phagocytes |
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Superantigens |
- Exotoxins that cause an intense immune response due to release of cytokines (Small protein molecules to regulate immune responses and mediate cellular communication) from host's T-cells (Lymphocytes that act against foreign organisms and tissue) - Excessive levels of cytokines leads to symptoms of fever, nausea, vomiting, diarrhea, shock and even death |
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Genotoxins
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- Damage the DNA and thus causing mutations, disrupting cell division and leading to cancer |
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Lipid A Portion (From the lipopolysaccharides of Gram Negative Bacteria cell walls) |
- Portion of the cell wall that is released during bacterial multiplication for gram negative bacterial or when it dies - Stimulates macrophages to release cytokines - Causes disseminated intravascular coagulation (small blood clots) |
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Endotoxin Salmonella typhimurium STD |
- Lipid portions of lipopolysaccharides of Gram negative bacteria cell walls that causes disseminate intravascular coagulation - Liberated when bacteria die or cell wall lyses, such as during multiplication - Do not promote formation of effective antitoxins, instead tend to enhance bad effect - Give 1 example of a bacteria that produces this |
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Exotoxins |
- Specific for a particular cell structure or function in the host (Ex: Nerves, gastrointestinal tract) - Unstable at high heat (Except: staphylococcal enterotoxin) - High toxicity - No fever, can be converted to toxoids to immunize, neutralized by antitoxin - Small lethal dose |
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Botulism Diphtheria Gas gangrene Scarlet Fever Tetanus BDGST (Building Street) |
5 Representative Diseases of Exotoxins |
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Endotoxins |
- Produces general symptoms such as fever, weaknesses, aches, shock, sometimes induce miscarriage - Stable at high heat, can withstand autoclaving - Low toxicity - Not easily neutralized by antitoxin, no effective toxoids can be made to immunize - Larger lethal dose |
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Typhoid Fever (Salmonella Typhi) Urinary Tract Infection (Proteus spp) Meningcoccal meningitis (Neisseria meningitides) TUM - SPN |
3 Representative Diseases of Endotoxins and their Bacteria |
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Cytopathic Effects (CPE) |
- Term referring to Visible effects of viral infection on a cell |
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- Stops cell synthesis - Lysosomes release enzymes - Inclusion bodies - Synctium: Fusing cells - Function change, chromosomal changes - Antigenic changes on surface - Contact inhibition loss - Production of Interferons protect uninfected cells |
8 Examples of Cytopathic Effects for host cell (Visible effects of viral infection) SS CCALII |
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- Respiratory Tract: Coughing/Sneezing - Gastrointestinal Tract: Feces/Saliva - Genitourinary tract: Urine/Genital secretions - Skin: Blood/Arthropods/Needles GGRS |
4 Examples of Portal of Exit for Pathogens, and examples |
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Respiratory Inhalation |
Common Cold, Pneumonia, Tuberculosis, Influenza, chicken pox and measles are diseases that can be contracted via the mucous membranes of the _____________ tract by ________________ (action)
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Gastrointestinal Ingestion (Food/Water) Hydrochloric Acid Bile |
Most are destroyed however by _______________ and enzymes in the stomach and ___________ and enzymes in the small intestine. |
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Genitourinary Sexual |
HIV infection, AIDS, genital warts, chlamydia, herpes, syphilis and gonorrhea are examples of pathogens that are contracted via the broken and UNBROKEN mucous membranes of the ____________ tract through _______________ contact. |
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Skin
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- Openings such as hair follicles and sweat gland ducts Ex: Hookworm larvae can pierce through even if intact, fungi |
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Conjunctiva
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- Relatively effective - Trachoma, ophthalmia neonatorum can be acquired through here |
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Parenteral Route |
- HIV, hepatitis viruses, tetanus, rabies, malaria and gas gangrene are examples of pathogens that can be transmitted this way |
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Coagulases |
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Kinases |
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Cytokines
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- Excessive amounts can cause fever, nausea, vomiting, diarrhea, shock and even death |
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Shock
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- It is called 'septic' when caused by bacteria and 'endotoxic' when caused by Gram-negative bacteria |
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Septic Shock |
- Shock caused by bacteria - Shock caused by Gram-negative bacteria |
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Tumor Necrosis Factor |
- Phagocytosis of gram-negative bacteria cause causes secretion of this factor from phagocytes - Sometimes called cachectin - Binds to many tissues in the body and alters their metabolism in a number of ways - Effects: Damage to blood capillaries, their permeability is increased, they lose large amounts of fluid, drop in blood pressure resulting in shock |
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- Inhibiting synthesis of viral proteins and host cell proteins - Kill virus-infected host cells by apoptosis |
Interferons protect uninfected cells from infections in two ways |
