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Uptake of naked DNA from the environment?
Transformation
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Fred Griffith's experiment proved the principle of_____ and what else?
Proved the principle of transformation and that DNA is the genetic material.
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A temporary physiological state during which transformation can occur
Competence
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Factors affecting transformation (3)
- Competence
- Specificity of DNA uptake
- Size & state of DNA
- *DNA quality is not necessarily a factor
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Newly emergent types of pneumococcal disease are canceling out what?
Herd immunity
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Which mode of horizontal gene transer requires a vector?
Transduction (via phage)
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Virus that infects bacterial cells?
Bacteriophage
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What determines a phage's tropism?
Tail fibers
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What is a phage's head capside made of?
Proteins
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Types of Phages:
1) Which one replciates within host cell leading to lysis?
2) Which one integrates into host chromosome and can remain quiescent?
- 1) Lytic
- 2) Temperate (Lysogenic)
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2 Types of transduction
- Generalized transduction
- Specialized transducation
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Which type of transduction is caused by packing errors?
What type of phage mediates this?
Which genes can be transferred?
- Generalized transduction
- Mediated by lytic phage
- Can transfer any bacterial genes
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Which type of transduction is caused by excision errors?
What type of phage mediates this?
Which genes can be transferred?
- Specialized transduction
- Mediated by lysogenic phage
- Can only transfer genes adjacent to phage integration site
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A property of a bacterial cell caused by the presence of a phage. (ex. E.coli is lysogenic for producing the Shiga toxin)
Lysogenic Conversion
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A phage that no longer can form infective phage particles although parts of it are retained due to a useful trait for the bacterium.
Defective prophage
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Which bacteria make an exotoxin and which make an endotoxin?
- Exotoxin- Streptococcus
- Endotoxin- Haemophilus
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Non-pathogenic bacteria can infect and replicate, but cause no harm. What is this called?
Sub-clinical infection (this can happen in an immune person)
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Infecting Dose 50 (ID50)
The number of organisms needed to infect half of the inoculated individuals.
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Lethal Dose 50 (LD50)
Number of organisms needed to kill half of the inoculated individuals.
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Genes on the chromosome that are common to almost all strains.
Core traits
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Genes that some strains have; expain hyper-virulent strains
Variable traits
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Antibodies that target a key virulence factor and thus provide protection from the bacterial disease.
Protectie Antibodies
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Diseases that are always present in a population at low levels.
Endemic
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Disease implies that the disease is occurring much more frequently than normal.
Epidemic
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World-wide epidemic
Pandemic
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Germiest public place is
- Gas pump handle
- (16.6% of cell phones have fecal bacteria)
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Organism proven to cause a particular disease.
Etiologic agent
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Koch's Postulates
- 1) Must find the organism in all cases, but not in healthy people
- 2) Must grow the organism in pure culture
- 3) Must use the pure culture to cause an experimental infection
- 4) Must isolate the organism in pure culture from the experimentally infected animal
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A sero-diagnosis is based on how much of an increase in Ab-titer during an infection
> or = 4
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Therapy that will cover many of the common causes.
Empiric therapy
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Spread of organism past the epithelial cell surface (or into a cell)
Invasiveness
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Time from acquisition of the organisms to the start of symptoms?
Incubation period
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Time during which there are non-specific symptoms, but can spread the bug
Prodromal period
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Specific signs and symptoms of the disease are present
Acute illness
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Time during which the illness subsides and patient returns to health
Recovery period
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Infections that involve organism that are found in the normal human flora
Endogenous infection
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Hospital acquired infections that are often endogenous infections.
Nosocomial infections
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Organisms that are not part of the human flora
Exogenous organism
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Healthy person who has an exogenous pathogen living in his/her flora
Carrier
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How many people die annually due to healthcare assocaited infections?
100,000
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2 Most troublesome bugs in hospital setting?
S. aureus, C. dificile
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Destroy neutrophils and macrophages
Leucocidins
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Bacteria have a ____ molecule at the end of their pili.
- Lectin
- Allow bacteria to bind to a specific sugar (change lectin --> change what they bind to)
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Which portion of LPS is toxic?
Lipid A (due to its branched fatty acids)
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Which part of LPS provides antigenicity?
Core carbohydrate
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R-antigen
No O-side chain on core carb. Colony appears rough. (Ab to R may help clear antigen)
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If O-side chain is present, what does the colony look like? What do you need Ab to?
- Smooth, round
- Ab to O antigen is normally protective (but there are tons of Gram-N O side chains so you won't have Abs to all of them)
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What part of LPS is needed for maximal virulence?
O antigen
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Which has a shorter outer chain, LOS or LPS?
LOS
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Endotoxin or exotoxin, which causes fever?
Endotoxin causes fever (stable up to 60 C)
Exotoxins typically lack fever
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Endotoxin or exotoxin, which requires only nanograms to be lethal?
Exotoxin
Endotoxin requires micrograms to be lethal.
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Endotoxin or exotoxin, which one has no toxid available?
Endotoxin
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Endotoxin or exotoin, which one is made up of proteins?
What is the other one made up of?
Exotoxin is made up of proteins.
Endotoxin is made up of Lipid A and carbs (think LPS).
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What do endotoxins bind to on B cells, macrophages, etc?
CD14, TL4
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Endotoxin binds to complement and triggers?
The alternalte complement pathway
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Endotoxin up-regulates expression of ______ on endothelial cells --> _______
Endotoxin up-regulates clotting factor on endothelial cells --> disseminated intravascular coagulation (DIC).
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What is used to test water to make sure it doesn not contain endotoxins?
Limulus Assay
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What determines the potentcey of the LPS?
Chemistry of fatty acids
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Injectosome is encoded by?
Type 3 Protein Secretion System
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Three components of LPS
- Lipid A
- Core carbohydrate
- O-side chain
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