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25 Cards in this Set
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Flagella
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Protein filaments that extend like long tails from the cell membranes of certain gram-positive and gram negative bacteria. It is used to move the cell around.
The tails are often several times the length of the bacterial cell |
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Basal Body
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Affixes the flagellum to the bacteria, it spans through the entire cell wall and binds to the inner and outer cell membrane
The basal body spins around causing the flagella to swing and this movement is called chemotaxis |
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What's an example of a bacteria with one polar flagella?
What's an example with with flagella all around the cell? What's an example with no flagella? |
Vibrio cholera have one polar flagella
Escherichia Coli has flagellas all around the cell Shigella does not have a flagella |
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Pili
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straight filaments arising from the bacterial cell wall, making the bacterium look like a porcupine, their purpose to adherence factors and are vital to their ability to cause disease
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Capsules
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protective walls that surround the cell membranes of bacteria
composed of simple sugar residues (rarely amino acids: Anthracis) enable bacteria to be more virulent because phagocytes and neutrophils are unable to encapsulate them |
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What are two tests that enable doctors to visualize capsules under the microscope?
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India ink stain, everything stains besides the capsule which looks like a halo around the cell
Quellung Reaction: Bacteria are mixed with antibodies that bind to the capsule |
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Opsonization
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the process of antibodies binding to the capsule
used in strep. pneumonia vaccine |
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Endospores
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metabolically dormant forms of bacteria that are resistant to heat (boiling) and have multiple layered coats outer layer called: exosporium
2 Genera produce spores: Bacillus and anaerobic Clostridium |
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Biofilms
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extracellular polysaccharide network similar to a capsule polysaccharides that forms a mechanical scaffold around the bacteria
it allows them to bind to prosthetic devices like catheters and protects them from antibiotic attacks |
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Facultative Intracellular Organisms
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Bacter that are phagocytosed by the host macrophage and neutrophils and survive within them
they escape the lysosome and peroxide toxins and are safe from antibodies within the cells |
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List the Facultative Intracellular Organisms
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Listeria monocytogenes, Salmonella typhi, Yersinia, Francisella tularensis, Brucella, Legionella, Mycobacterium
Mnemonic: Listen Sally Yer Friend Bruce Must Leave |
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Exotoxins
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proteins released by bacteria that cause disease
released mostly by gram positive bacteria, some gram negative release it exotoxins include anthrax, botulism, tetanus, and cholera |
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Neurotoxins
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Exotoxins that act on the nerves or motor endplates to cause paralysis. Tetanus toxin and botulinum toxin are examples.
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Enterotoxins
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exotoxins that act on the grastrointestinal tract to cause diarrhea. They inhibit resorption of NaCl, activate NaCl excretion, or kill epithelial cells. It results in osmotic pull of fluid into the intestine causing diarrhea. Either Infectious diarhea or Food Poisoning.
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Infectious Diarrhea
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Bacteria that colonizes and binds to GI tract continuously releasing their enterotoxins. They continue to grow unless stopped by immune system or antibiotics.
Examples: Vibrio cholera, E. Coli, Campylobacter jejuni, Shigella dysenteriae |
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Food Poisoning
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Bacteria that grows in the food and release enterotoxin in the food, its ingested and results in diarrhea vomiting for less than 24 hours
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Pyrogenic exotoxins
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stimulate the release of cytokines and can cause rash, fever, and toxic shock syndrome, examples staph. aureus and pyogenes
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Tissue Invase Exotoxins
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allow bacteria to destroy and tunnel through tissue. includes enzymes that destroy DNA, collagen, fibrin, NAD, RBCs and WBCs
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Exotoxin Subunits
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in major exotoxin bacteria composed of two polypeptide subunits bound by disulfide bridges. one called B for binding and the other A for action
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Endotoxin
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remember it is Lipid A in the outer membrane of LPS of gram negative bacteria. its released when the cell lyses
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Septic Shock
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a common and deadly response to bacterial infection, also referred to endotoxic shock because it is often triggered by endotoxins, causing dangerous drop of blood pressure and organ dysfunction
Body releases Tumor Necrosis Factor (TNF) which causes hypotension and shock |
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Bacteremia
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bacteria in the blood stream, can be seen by blood culture
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Sepsis
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Bacteria that causes a systemic immune response to the infection, high fever, fast heart rate, heightened WBC count
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Treatment of Septic Shock
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1) Find site of infection (commonly the lungs, followed by abdomen and urinary tract)
2) Quick antibiotic therapy 3) Support Blood Pressure |
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4 Bacteria that produce exotoxins that increase cAMP levels
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cholera
Anthrax Motezuma's revenge (enterotoxic E. Coli) Pertussis (Bordetella pertussis) |