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250 Cards in this Set
- Front
- Back
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Bacteria Structure: Basic or Special?
Cell Wall |
Basic
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Bacteria Structure: Basic or Special?
Flagellum |
Special
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Bacteria Structure: Basic or Special?
Plasma Membrane |
Basic
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Bacteria Structure: Basic or Special?
Fimbria |
Special
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Bacteria Structure: Basic or Special?
Chromosome |
Basic
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Bacteria Structure: Basic or Special?
Pilus |
Special
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Bacteria Structure: Basic or Special?
Ribosomes |
Basic
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Bacteria Structure: Basic or Special?
Glycocalyx |
Special
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Bacteria Structure: Basic or Special?
Plasmid |
Special
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Bacteria Structure: Basic or Special?
Inclusions/Granules |
Basic
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Bacteria Structure: Basic or Special?
Spore (endospore) |
Special
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Appendages of Bacteria
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1. Flagellum
2. Fimbria 3. Pilus |
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Bacteria: Cell Envelope Contents
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1. Glycocalyx
2. Cell Wall 3. Plasma membrane |
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Bacteria: Cytoplasm Contents
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1. Chromosome (nucleoid)
2. Ribosomes 3. Inclusion (granule) |
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What is the flagellum attached to on a bacterial cell?
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The cell membrane
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What are the 3 parts of the flagellum structure?
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1. Filament
2. Hook 3. Basal Body |
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Flagella Arrangements: Monotrichous
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Single flagellum at one end
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Flagella Arrangements: Lophotrichous
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Clusters of flagella at one end
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Flagella Arrangements: Amphitrichous
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A flagellum at each end
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Flagella Arrangements: Peritrichous
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Flagella distributed over the entire surface of the bacterial cell
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Which Flagella arrangement produces the slowest movement?
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Peritrichous (too many cooks in the kitchen)
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What is the rotation of the RUN movement for bacteria?
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Counterclockwise rotation of flagellum
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What is the rotation of the TUMBLE movement for bacteria?
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Clockwise movement of the flagellum (changing direction)
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Function of fimbriae?
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-Attachment to other bacteria
-Colonization |
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Function of pilus?
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-Pathway for DNA to be transferred from one cell to another (conjugation)
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Superficial to Deep structures of Cell Envelope
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Glycocalyx-Cell Wall-Cell Membrane
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What is the glycocalyx usually composed of?
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Polysaccharides
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What are the two types of Glycocalyx?
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1. Slime Layer
2. Capsule |
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Slime Layer type of Glycocalyx: Properties
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Thin
Loosely Organized Irregular Structure |
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Capsule type of Glycocalyx: Properties
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Thick
Highly Organized Regular Structure |
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What are the functions of the Glycocalyx?
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Bacterium Adhesion
Protection |
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What stain is used to visualize the glycocalyx layer of the cell envelope?
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Indian Ink Stain
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Which cell wall component is unique to bacteria?
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Peptidoglycan
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Which bacterial structure is a major target for antibiotics?
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Cell Wall
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What is Gram Staining?
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A stain that separates bacteria into 2 large groups based on the chemical and physical properties of their cell wall
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What chemical is used during the STAINING step of the Gram Stain?
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Crystal Violet is used in the staining step
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What chemical is used during the FIXING step of the Gram stain?
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Iodine is used during the fixing step
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What chemical is used during the DECOLORIZATION step of the Gram stain?
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Acetone is used during the decolorization step
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What chemical is used during the COUNTERSTAINING step of the Gram stain?
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Safranin is used during the counterstaining step
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What is the space between the layers of the cell membrane & peptidoglycan layer, in Gram (-) also the space between the outer membrane & peptidoglycan layer?
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Periplasmic space
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What are the 2 acidic polysaccharides bound to the peptidoglycan layer in Gram (+) bacteria?
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1. Teichoic acid
2. Lipoteichoic acid |
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What 3 structures compose a subunit of peptidoglycan?
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NAG (N-acetylglucosamine)
NAM (N-acetylmuramic acid) Tetrapeptide attached to NAM |
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The arrangement of which bacterial structure is responsible for the rigidity and porosity?
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Peptidoglycan
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What would happen if a Gram (+) cell lost it's teichoic acid and lipoteichoic acid?
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It would die
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Where does teichoic acid attach to?
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Peptidoglycan layer
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Where does lipoteichoic acid attach to?
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Cell membrane
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What is Beta-lactamase and where is it located?
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-enzyme that degrades penicillin antibiotics
-contained in periplasmic space |
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What two structures are present in the outer wall of Gram (-) bacteria?
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LPS
Porins |
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What are the three components of LPS?
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1. Lipid A
2. Core polysaccharide 3. O Antigen |
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Which component of LPS contributes to its toxicity?
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Lipid A
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Which component of LPS contibues to antigen diversity?
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O Antigen
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What chemical is used during the STAINING step in an Acid Fast Stain?
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Carbol fuchsin
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What chemical is used during the FIXING step in an Acid Fast Stain?
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Phenol
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What chemical is used during the DECOLORIZATION step in an Acid Fast Stain?
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Acid/Alcohol
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What chemical is used during the COUNTERSTAINING step in an Acid Fast Stain?
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Methylene Blue
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Which bacterial structure is the target for antimicrobial peptides( ex. defensins)?
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Cell membrane
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What enzyme helps to condense bacterial DNA?
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Gyrase
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Which type of Gram bacteria have spores?
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ONLY Gram (+)
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What kind of stain is utilized for spores?
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Malachite Green Stain
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Which stage of bacterial growth is most sensitive to antibiotic agents?
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Log phase
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What are the 6 requirements affecting bacterial growth?
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1. Temperature
2. pH 3. Oxygen 4. Water 5. Light 6. Nutrients |
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What is the optimum temperature range for mesophiles?
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20 - 45 degrees Celsius
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What is the optimum temperature range for thermophiles?
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45-110 degrees Celsius
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What is the optimum temperature range for psychrophiles?
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0-20 degrees Celsius
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What kind of temperature & pH classification are most bacteria?
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mesophiles (20-45 degrees C)
neutrophiles (5-8 pH) |
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What is the optimum pH range for neutrophiles?
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5-8 pH
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What is the optimum pH range for acidophiles?
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0-5 pH
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What is the optimum pH range for alkalinophiles?
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8-12 pH
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How does oxygen affect the growth of Obligate Aerobes?
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oxygen is required for growth
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How does oxygen affect the growth of Microaerophiles?
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oxygen is required at small levels for growth (2-10% oxygen)
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How does oxygen affect the growth of Obligate Anaerobes?
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oxygen is toxic
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How does oxygen affect the growth of Facultative bacteria?
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oxygen is not required for growth but it can be utilized when available
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How does oxygen affect the growth of Aerotolerant anaerobes?
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oxygen is not required and is not utilized
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What are the three detoxifying enzymes that obligate anaerobes lack?
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Superoxide dismutase
perioxidase catalase |
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What kind of bacteria is UV light toxic for?
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Eubacteria
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What are the 5 basic nutrients for bacterial growth?
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1. Carbon
2. Nitrogen 3. Hydrogen 4. Oxygen 5. Minerals & trace elements |
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What kind of energy gathering organisms are most bacteria?
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Chemoheterotrophs
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Which facet of metabolism consumes energy?
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Anabolism
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Which facet of metabolism produces energy?
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Catabolism
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What are the 2 primary energy storage molecules?
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ATP
GTP |
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How do primary energy storage molecules release energy
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Phosphatase cleaves the phosphate bond --> releases energy
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What are the 2 secondary energy storage molecules ?
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NADH
FADH2 |
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How do secondary energy storage molecules yield ATP?
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Electron Transport Chain
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How many ATP are produced from 1 NADH through the ETC?
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3 ATP
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How many ATP are produced from 1 FADH2 through the ETC?
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2 ATP
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What 3 reactions does glucose go through in an aerobic system?
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1. Glycolysis
2. TCA 3. ETC |
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What 2 reactions does glucose go through in an anaerobic system?
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1. Glycolysis
2. Fermentation |
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What is the end product of glycolysis
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2 molecules of Pyruvate
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What molecule enters the TCA cycle?
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pyruvate
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What is another function of the TCA cycle other than energy production?
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oxidation of amino acids, fatty acids, and carbohydrates
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What kind of energy storage molecules go through the ETC?
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Secondary energy storage molecules
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How many ATP are produced in aerobic glucose catabolism?
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38 ATP
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How many ATP are produced in anaerobic glucose catabolism?
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2 ATP
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What are the end products of anaerobic catabolism used for?
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Identification in bacteria
Industrial processes |
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In what kind of cells is the Entner-Duodoroff pathway restricted to?
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Prokaryotic cells
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What did the Frederick Griffith mice experiment demonstrate?
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Transformation
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What is transformation?
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Live cells pick up DNA that dead cells leave behind
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What kind of DNA enters the cell during transformation (double stranded or single stranded?)
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Single stranded
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Which mineral is required during DNA transfer in transformation?
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Calcium ion
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Cells capable of taking up exogenous DNA are called what?
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Competent cells
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Does transformation occur at a high frequency?
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No, it occurs at a low frequency
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Which protein promotes the DNA exchange exchange between the donor fragment and the recipient DNA?
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Rec A protein
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Under what kind of conditions does natural transformation occur?
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Nutritional shortage or adverse condition
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Can both Gram - and Gram + utilize transformation?
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Yes
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In what phase of growth do bacterial develop competence?
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Late Log phase (need dead & living cells)
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What is conjugation?
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DNA transfer during cell-to-cell contact through sex pilus
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Can F+ cells conjugate with other F+ cells?
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No
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What is encoded on the F plasmid?
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the sex pilus genes
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In what kind of cells does the F plasmid integrate into its DNA?
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High Frequency Recombination Cells
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What kind of cells can transfer their entire chromosome during conjugation?
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High Frequency Recombination Cells
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What is transduction?
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DNA exchange mediated by bacteriophages
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What part of the genome can be transferred in general transduction?
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Any host gene
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What part of the genome can be transferred in specific transduction?
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Only specific host genes
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What are the two things that compose bacteriophages?
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DNA & protein
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Which life cycle does general transduction produce?
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The lytic cylce
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Which life cycle does specific transduction produce?
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The lysogenic cycle & lytic cycle
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Does transposition happen between cells?
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No, it happens within a cell
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What kind of genes are within the insertion sequence of a transposon?
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transposase gene
or antibiotic resistance genes |
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What kind of sequences are at the ends of a transposon?
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Palindromic sequences
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What four factors are influenced by bacterial gene transfer?
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1. Colony morphology
2. Biochemical activity 3. Virulence 4. Drug resistance |
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What are the 4 differences between prokaryotic cells and eukaryotic cells that help antibiotics distinguish bacteria and animal cells?
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1. Presence of cell wall
2. Histones-animal cell Gyrase & topoisomerase IV-prokaryote 3. RNApol II-animal cell RNApol I-prokaryote 4. 80S (60S + 40S) ribosome-animal 70S (50S + 30S) ribosome-prokaryote |
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In what cellular compartment is the tetrapeptide added to NAM?
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Cytoplasm
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What does bactoprenol do?
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It transports peptidoglycan monomers to the periplasmic space
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What is the chronology of the peptidoglycan monomer building?
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Tetrapeptide-NAM
Tetrapeptide-NAM-bactoprenol Tetrapeptide-NAM-NAG-bactoprenol |
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Where is peptidoglycan produced?
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Cell membrane
|
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How do the peptidoglycan monomers arrange into the ultimate structure of peptidoglycan?
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1. Autolysins break glycosidic bonds between monomers
2. Autolysins break peptide cross bridges 3. New monomers added |
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What bond does Transglycosylase catalyze the formation of?
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Sugar-Sugar bond between NAM & NAG
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What bond does Transpeptidase catalyze the formation of?
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peptide bond between peptidoglycan rows
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What are anti-microbial agents?
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Chemical substances that kill or inhibit the growth of microbes
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What are the 3 groups of anti-microbial agents?
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1. Natural agent
2. Semi-synthetic agent (modified natural) 3. Synthetic agent |
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Which antibiotics are inhibitors of 30S ribosome subunit binding?
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Aminoglycosides
Tetracylcines |
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Which antibiotics are inhibitors of 50S ribosome subunit binding?
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Chloramphenical
Clindamycin Macrolides Oxazolidinones |
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What are the 5 examples of aminoglycosides (30S inhibitors)?
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1. Streptomycin
2. Kanamycin 3. Neomycin 4. Tobramycin 5. Gentamicin |
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What are the 5 basic sites of antibiotic activity?
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1. Cell wall synthesis
2. Cell membrane integrity 3. Nucleic acid synthesis 4. Protein synthesis 5. Biosynthesis pathways |
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Which 3 antibiotics inhibit peptidoglycan synthesis?
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1. Beta-lactam antibiotics
2. Vancomycin 3. Bacitracin |
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Which 4 antibiotics inhibit acid fast cell wall synthesis?
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1. Isoniazid
2. Cycloserine (for Mycobacteria) 3. Ethionamide 4. Ethambutol |
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What two proteins do beta-lactam antibiotics target and inhibit?
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1. Transglycosylase
2. Transpeptidase |
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Are beta-lactam antibiotics bactericidal or bacteriostatic?
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Bactericidal
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What is the target of Vancomycin antibiotics?
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The Ala terminus of the peptidoglycan precursor, preventing the formation of glycosidic bonds & peptide bones
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Can Vancyomycin be used against Gram (-) bacteria?
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No, because it cannot penetrate the outer membrane of Gram (-) bacteria
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Do Vancomycin antibiotics bind to transglycosylase or transpeptidase?
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No, it binds to the Ala terminus of the peptidoglycan precursor thus inhibiting TP & TG activity
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What do Bacitracin antibiotics inhibit?
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Cell wall synthesis
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How do Bacitracin antiobiotics inhibit cell wall synthesis?
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They inhibit bactoprenol from transporting peptidoglycan monomers to the periplasmic space
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What are the 4 major groups of Beta-lactam antibiotics?
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1. Penicilins
2. Cephalosporins 3. Carbapenems 4. Monobactams |
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What are the 2 major groups of cell wall synthesis inhibitors that are not beta-lactam antibiotics?
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1. Vancomycin
2. Bacitracin |
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How does isoniazid block acid fast cell wall synthesis?
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It blocks the incorporation of mycolic acid into acid fast cell walls
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How does ethambutol block acid fast cell wall synthesis?
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It interferes with the incorporation of arabinogalactan into acid fast cell walls
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What are the 5 major components of acid fast cell walls?
|
1. LAM
2. Outer lipids 3. Mycolic acid 4. Phosphatidylinositol Mannoside 5. Arabinogalactan |
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How do Polymyxins inhibit cell wall integrity?
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Bind to membrane phospholipids & cleave membrane (loss of contents)
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Can polymyxin antibiotics be effective against gram (+) bacteria?
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No, because they cannot diffuse through the thick peptidoglycan layer
|
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Which of the discussed antibiotics are limited to topical usage and is toxic if ingested?
|
Polymyxins
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Are polymyxins bactericidal or bacteriostatic?
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Bactericidal
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What is the result of aminoglycoside binding to 30S ribosome?
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1. Inhibit protein synthesis
2. Aberrant (abnormal) protein synthesis |
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What kind of bacteria are resistant to aminoglycosides?
|
Anaerobic bacteria because O2 is required to penetrate outer membrane
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In the 30S ribosome binding group of antibiotics, which type binds reversibly and which is irreversible?
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Aminoglycosides- Irreversible
Tetracyclines- Reversible |
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What is the main group of DNA replication inhibitors?
|
Quinolones
|
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What DNA replication molecules do Quinolones bind to?
|
Gyrase & Topoisomerase type IV
|
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What is the main group of RNA transcription inhibitors?
|
Rifamycins
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What RNA transcription molecule do rifamycins bind to?
|
RNA pol (beta subunit)
|
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What part of bacterial RNA transcription do rifamycins inhibit?
|
Initiation
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What are the 2 folic acid synthesis inhibitors?
|
1. Sulfonamide
2. Trimethoprim |
|
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Which antibiotics are the only groups that are bacteriostatic?
|
1. Protein synthesis inhibitors (except aminoglycosides)
2. Folic acid synthesis inhibitors |
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What are the 3 types of sensitivity tests for antibiotics against specific strains of bacteria?
|
1. Disk diffusion method (Kirby-Bauer)
2. Broth or agar dilution method 3. E-test |
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What is the difference between MIC & MBC?
|
MIC only measures the minimum inhibitory concentration that inhibits VISIBLE growth of a microorganism
MBC measures the amount needed to literally kill the entire population |
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What are the 4 mechanisms of antibiotic resistance?
|
1. Reduced drug accumulation
2. Drug inactivation or modification 3. Alteration of drug target site 4. Alteration of biosynthesis |
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What are the two modes of reduced drug accumulation?
|
1. Decreasing permeability to antibiotic
2. Increasing efflux of antibiotic |
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What 4 genetic processes drive acquired resistance?
|
1. Transformation
2. Conjugation 3. Transduction 4. Spontaneous mutation |
|
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What are the 2 mechanisms of beta-lactam resistance?
|
1. Beta-lactamase enzymes
2. Altering the PBPs to decrease binding affinity |
|
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How do beta-lactamase enzymes inactivate beta-lactam antibiotics?
|
They hydrolyze the beta-lactam ring structure
|
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What are 2 ways that bacteria alter the PBPs to battle the effects of antibiotic binding?
|
1. Gene mutations
2. Overproduction of PBPs |
|
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Are vancomycin antibiotics effective against Gram (-) bacteria?
|
No, because they are too big to pass through the outer membrane
|
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What are 2 ways that bacteria can be resistant to vancomycin antibiotics?
|
1. Gram (-) bacteria are naturally resistant
2. Different tetrapeptide terminus that will not bind vancomycin |
|
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What kind of host relationship is characteristic of pathogenic bacteria?
|
Parasitism
|
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Which 2 types of host-bacteria relationships result in disease?
|
Opportunism & Parasitism
|
|
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When can normal flora become pathogenic in an opportunistic relationship?
|
When inoculated in the "wrong" places
or when host is immuno-compromised |
|
|
What are the 3 portals of entry for bacteria?
|
1. Ingestion
2. Inhalation 3. Direct Penetration |
|
|
What are the 3 general steps of bacterial infection in order?
|
1. Colonization/Adhesion
2. Invasion 3. Multiplication |
|
|
What are the 4 factors in the colonization step of an infection?
|
1. Fimbria
2. Glycocalyx 3. Teichoic acid & lipoteichoic acid (only Gram (+) 4. Adhesins |
|
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Do adhesins always bind to specific receptors?
|
No, sometimes they are nonspecific
|
|
|
Why are adhesins good vaccine candidates?
|
They are essential to infection and they are readily accessible to antibodies
|
|
|
How do invasins affect the host?
|
Locally damage cells
Facilitate the growth and spread of the pathogen |
|
|
What are factors for the multiplication step in bacterial infection?
|
1. competing with other bacteria for nutrients
2. avoid being killed or removed by immune system |
|
|
What are the 4 major components of innate immunity?
|
1. Phagocytes
2. Complement system 3. Inflammatory Response 4. Fever |
|
|
What are the 4 steps of phagocytosis?
|
1. Engulfment
2. Formation of phagosome 3. Phagosome + Lysosome fusion (phagolysosome) 4. Pathogen digested and pushed out through exocytosis |
|
|
What are the effects of the complement system?
|
1. Opsonization (enhancing phagocytosis)
2. Cytolysis (pore formation) 3. Inflammation (histamine) |
|
|
What are 3 general ways that bacteria try to overcome the host defense?
|
1. Inhibit phagocytosis
2. Destroy immune system 3. Intracellular growth |
|
|
How can bacteria overcome the engulfment step in phagocytosis?
|
Glycocalyx interferes with opsonization
|
|
|
How can bacteria overcome the phagosome formation step in phagocytosis?
|
Lyse phagosome membrane and escape
|
|
|
How can bacteria overcome the phagolysosome step in phagocytosis?
|
Inhibit formation or are resistant to lysosome enzymes
|
|
|
What are 2 ways that bacteria can destroy the immune system?
|
1. Periodically change their antigens to avoid detection
2. Degrade complement proteins or antibodies |
|
|
What are the 2 broad qualities of bacteria that determine how they cause disease?
|
1. Invasiveness
2. Toxicity |
|
|
What are the 3 categories of exotoxins?
|
1. Cell surface acting toxins
2. Toxins that need to enter cell 3. Toxins directly delivered to host |
|
|
What are 2 examples of cell surface acting toxins?
|
1. Superantigens
2. Pore forming toxins |
|
|
What is an example of a toxin that needs to enter the cell?
|
A/B toxin
|
|
|
What is an example of exotoxins directly delivered to the host cell?
|
Type III and IV secretion systems
|
|
|
What are the 5 aminoglycoside antibiotics?
|
1. Streptomycin
2. Kanamycin 3. Neomycin 4. Gentomycin 5. Tobramycin |
|
|
What are the 3 tetracyline antibiotics?
|
1. Tetracyline
2. Doxycycline 3. Minocycline |
|
|
What are the 2 folic acid synthesis inhibitors?
|
Sulfonamide & Trimethoprim
|
|
|
What is the effect on surrounding RBCs in a Beta-hemolytic result of a Hemolysis test?
|
Complete lysis of RBCs & Clear halo
|
|
|
What is the effect on surrounding RBCs in a Gamma-hemolytic result of a Hemolysis test?
|
No Hemolysis
|
|
|
What is the effect on surrounding RBCs in a Alpha-hemolytic result of a Hemolysis test?
|
Incomplete lysis & Greenish halo
|
|
|
What is the chemical indicator used in Fermentation assays?
|
Phenol Red
|
|
|
What does a yellow color indicate in a fermentation assay using phenol red?
|
Fermentation ( Anaerobic bacteria)
|
|
|
What does a red color indicate in a fermentation assay using phenol red?
|
No Fermenation ( Aerobic bacteria)
|
|
|
What are the 3 basic serological tests for bacteria identification?
|
1. ELISA
2. Western Blot 3. Radioimmunoassay |
|
|
How is 16S ribosomal RNA used in bacteria identification?
|
It is the RNA component of the 30S ribosome of bacteria and very well conserved in prokaryotes
|
|
|
What are the 5 basic characteristics used in bacteria identification?
|
1. Morphological
2. Biochemical 3. Serological 4. Genomic 5. Growth |
|
|
What are the 3 major Gram + Cocci Genera?
|
1. Streptococci
2. Staphylococci 3. Enterococci |
|
|
What is the result of a Catalase assay between the 3 major Gram + Cocci genera?
|
Staphylococci -->positive
Streptococci-->negative Enterococci-->negative |
|
|
What is the host relationship for Staphylococci?
|
Opportunistic
|
|
|
What are the 3 major species for Staphylococci?
|
S. aureus
S. epiddermidis S. saprophyticus |
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What is the oxygen requirement for Staphylococci?
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Facultative
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What is the result of a Coagulase assay between the Staphylocci species?
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S. aureus-->positive
S. epidermidis-->negative s. saprophyticus-->negative |
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Which is the most virulent Staphylococcus species?
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S. aureus
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Which Staphylococcus species is the most isolated nosocomial pathogen?
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S. aureus
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What are the enzyme virulence factors for S. aureus
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1. Coagulase
2. Catalase 3. Hyaluronidase 4. Fibrinolysin 5. Lipase 6. Nuclease 7. Penicillinase |
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What are the structural component virulence factors for S. aureus?
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1. Glycocalyx
2. Peptidoglycan 3. Teichoic acid 4. Protein A (of LPS) |
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What are the toxin virulence factors for s. aureus?
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1. Cytotoxins
2. Exfoliative toxins 3. Enterotoxin 4. Toxic Shock Syndrome Toxin-1 |
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What disease is associated with Exfoliative toxins?
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Staphylococcal scalded skin syndrome (SSS)
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What kind of proteases are Exfoliative toxins?
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Serine proteases
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What kind of exotoxins are Enterotoxins?
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Superantigens
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What disease do enterotoxins cause?
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Food poisoning
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What kind of exotoxin is Toxic Shock Syndrome Toxin-1?
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Superantigen
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What is the function of Coagulase?
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Cause blood clot by converting fibrinogen to fibrin, prevent phagocytosis
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What is the function of Catalase?
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Catalyze removal of hydrogen peroxide
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What is the function of Hyaluronidase?
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Hydrolyze hyaluronic acids in connective tissue, spreads staphylococci
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What is the function of Fibrinolysin (Staphylokinase)?
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Dissolves fibrin clots
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What is the function of Lipase?
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Hydrolyze lipids, promotes invasion in cutaneous and subcutaneous tissues
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What is the function of Nuclease?
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Hydrolyzes DNA, useful in identifying S. aureus
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What is the function of Penicllinase?
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Hydrolyzes penicllins, imparts beta-lactam antibiotic resistance
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What is the function of the Glycocalyx as a virulence factor of S. aureus?
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inhibits phagocytosis
promotes bacterial adherence |
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What is the function of peptidoglycan as a virulence factor of S. aureus?
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endotoxin-like activity
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Under the products liability theories, what defenses are available under the theory of:
[1] Negligence; [2] Strict Liability; [3] Implied Warranties (a) Merchantability & (b) Fitness for a Particular Purpose)? |
[1] Negligence: Assumption of the risk and any type of contributory negligence;
[2] Strict Liability: In Contributory Negligence States – assumption of the risk and unreasonable misuse (failure to discover or guard against defect is NOT a defense); in Comparative Negligence States – any type of fault (under type of fault (under state’s comparative negligence rules); [3] Implied Warranties of Merchantability and Fitness for a Particular Purpose: In Contributory Negligence States – Assumption of the risk, unreasonable misuses, and failure to give reasonable notice of breach; In Comparative Negligence States – Any type of fault (under state’s comparative negligence rules) |
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What is the function of Protein A as a virulence factor of S. aureus?
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Inhibits antibody response by binding to the Fc receptor of IgGs
Inhibits phagocytosis by inhibiting opsonization Note: not present in S. epidermidis or S. saprophyticus |
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Can S. aureus invade through intact skin?
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NO, infection usually begins with traumatic inoculation
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What are the 3 general disease types caused by S. aureus?
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1. Cutaneous infection (most common)
2. Toxin-mediated syndromes 3. Systemic diseases |
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What are the 4 types of cutaneous infections caused by S. aureus?
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1. Impetigo
2. Folliculitis 3. Carbuncles 4. Wound infection |
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What are the 2 toxin-mediated syndromes caused by S. aureus?
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1. Food poisoning
2. Scalded Skin Sydrome |
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What are the 2 systemic diseases caused by S. aureus?
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1. Bacteremia (endocarditis & osteomyelitis)
2. Pneumonia |
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What is S. epidermidis especially good at forming?
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Famous biofilm former
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What is the virulence factor for S. epidermidis?
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Glycocalyx
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What are 2 major diseases associated with S. epidermidis?
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1. Endocarditis in valve replacement surgery
2. Prosthetic joint infection |
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What does S. saprophyticus cause?
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1. Urinary Tract Infection among women
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Are S. saprophyticus easily controlled by antibiotics?
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YES
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What kind of staphylococci infections is direct microscope observation most useful?
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Pyogenic infections
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Between which two Staphylococcus species does a Novobiocin assay distinguish?
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S. epidermidis & S. saprophyticus
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How is S. aureus distinguished between the other Staphylococcus species in a blood agar test?
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It has yellow colonies as opposed to white
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Is S. aureus Novobiocin sensitive?
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Yes
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Which Staphylococcus species are Novobiocin sensitive?
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S. aureus & S. epidermidis
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How is S. aureus distinguished in a mannitol fermentation test?
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S. aureus would produce a yellow color indicative of fermentation
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