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23 Cards in this Set
- Front
- Back
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What is the significance of opportunistic pathogens?
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They are not considered pathogenic in normal healthy persons but cause disease when defendes in the host cells are down. Examples include pseudomonas and candid albicans
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What is virulence?
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The degree of pathogenicity determined by the ability of a microbe to establish itself in an host and cause infection.
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Describe microbial antagonism
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The antagonistic effect "good" microbes have against intruders.
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What are bacteroides?
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Intestinal bacterium that work as microbial antagonists.
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Explain why the GI tract is not sterile as are other internal organs.
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It is not a "closed" system. It has numerous openings including the mouth and anus that allow microbes to enter and become normal residence.
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How many species reside in the mouth and what are the most common?
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Approx, 600, commonly Streptococcus species
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What is dextran?
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The slime layer formed by S. mutans and S. sanguis in the presence of simple sugars. Colonization causes dextrin to build a biofilm that attracts other bacteria.
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Name the parts of the respiratory system that contain normal residential bacteria.
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Nasal mucosa, vestibule, nasal cavity, epiglottis, soft palate, and trachea.
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T or F: The stomach and small intestine harbor significant amounts of residential microbes? If F, correct.
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False. The oral cavity, pharynx and colon harbor significant amounts of residential microbes in numbers as high as 10 to the 11th power per gram of feces.
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Name the bacteria in the vagina that ferments in order to lower the pH during childbearing years to 4.5.
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Lactobacillus
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What does axenic mean?
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Germ free
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What is the negative effect of the immune system of germ free animals?
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They lack certain white blood cells and therefore a slower immune response. When they come in contact with normal control animals, they can become infected and die from seemingly insIgnificant diseases.
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What are true pathogens? Give examples.
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Primary pathogens are capable of causing disease in normal healthy individuals.Examples include influenza, malaria, and plague,
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What are gnomobiotic studies?
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Germ free subjects Are inoculated with a single type of microbe to determine its individual affect
or with several known microbes to determine interrelationships. |
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Name some main portals of entry
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Skin
GI tract Respiratory tract Urogenital tract |
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What is infectious dose?
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The number of microbes required to infect a host cell. Microbrpes with the smallest infectious dose have the highest virulence.
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What are the phases of infection?
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1. Establishment...portals of entry
2. Adhesion/attachment 3. Invasion 4. Release (portals of exit) |
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Name the common infections of the fetus
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STORCH
syphilis Toxoplasmosis Other disease (hep B, AIDS, Chlamydia) Rubella Cytomegalovirus Herpes simplex |
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What are the most serious complications of STORCH infections?
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Spontaneous abortion
Stillbirth Congenital abnormalities Brain damage Prematurity |
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Explain antiphagocytic factors
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Factors that kill phagocytes in order to get past the resistance they are met with in entering a system with the goal to infect.
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What are exotoxins? Endotoxins?
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Exotoxins is a toxin molecule secreted by a bacterial cell into infected tissues.
Endotoxins are not secreted but rather released after the cell isndamaged or lysed. |
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Give an example of exotoxins and explain how they act
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Hemolysins are bacterial exotoxins that disrupt the cell membrane of red blood cells, causing the cells to burst and release hemoglobin.
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What are A-B toxins
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They consist of two parts: A (active component) and B (binding component). B acts first, binding to a specific receptor cite. A acts as a catalyst that inactivates a normal cell protein.
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