Flashcards in Skinny bacteria II Deck (73):
What is the result for alpha, beta, and gamma hemolysis?
alpha = partial/green
beta = total
gamma = none
What are the lancefield antigens?
Cell wall carbs used to define beta-hemolytic into groups A through U
What is GAS?
What is GBS?
What is GDS?
What are the two groups of strep that do not get lancefield designations?
What are the four major diseases GAS is responsible for?
How do you differentiates GAS from other Beta hemolytic strep?
GAS is bacitracin sensitive
What are the three major virulence factors for GAS?
Hyaluronic acid capsule
What is significant about that capsule of GAS
Hyaluronic acid is a poor immunogen (looks like self) and interferes with phagocytosis
What are the two toxins of GAS?
What is the M protein found on Strep A? (3)
Myosin-like protein that:
-allows for attachment
-Inhibits complement attack
What is the function of streptolysin O and streptolysin S?
Pore forming toxins
What percent of GAS produce superantigens?
What are the superantigens that some strep produce? What are their function?
Pyrogenic exotoxins SpeA, SpeB, SpeC
Increase proinflammatory cytokine production
What is the function of C5a peptidase of GAS?
Prevents complement formation, and PMN chemotaxis
Strep gets into a cell using what protein? What happens then?
Produces more causing apoptosis of the cell
What are the four major skin infections caused by strep?
How can you distinguish between staph and strep impetigo?
Staph is more extensive, with bullous lesions
Sharply demarcated erythematous skin = ?
NOT sharply demarcated erythematous and warm skin = ?
What bacteria is the most common cause of cellulitis?
GAS causes what % of necrotizing fasciitis?
What are the symptoms of necrotizing fasciitis? (2)
Grayish skin coloration initially, moving to erythema and edema
What is the treatment for necrotizing fasciitis?
Prompt debridement and removal of tissue
Broad spectrum Abx
What causes scarlet fever? Symptoms?
Strep pyogenes exotoxin Spe
Strawberry tongue + Petechial rash = ?
What are the complications of acute rheumatic fever? What causes it?
Heart valve tissue damage
d/t cross rxn w/ M protein and type II hypersensitivity
Glomerulonephritis is a complication of what?
Pharyngeal OR cutaneous GAS
What type of hypersensitivity is glomerulonephritis?
When does glomerulonephritis present?
1-4 weeks post GAS pharyngitis or 3-6 week post cutaneous infection
Symptoms of glomerulonephritis? (3)
Recent strep infx
Reduced serum complement
Strep toxic syndrome usually follow what disease?
Necrotizing fasciitis caused by strep
True or false: Strep toxic syndrome is the result of bacteremia
How do you diagnose GAS, besides serology and culture?
**Antistreptolysin O abs**
What is the treatment for GAS? Is staph susceptible to this?
PCN--staph would be resistant to this
What is the gram stain and morphology of pseudomonas aeruginosa? Hemolysis pattern? Oxidase? Ferment?
Gram negative motile rod
Is staph sensitive to PCN?
no, has beta lactamases
Where can pseudomonas grow?
Anywhere there is water--even soap
Blue green pigment on agar = ?
Pseudomonas aeruginosa usually are associated with what?
True or false: Pseudomonas aeruginosa is an opportunistic pathogen, and has loads of abx resistance
What are the soluble pigments that Pseudomonas aeruginosa produces?
What is the capsule associated with Pseudomonas aeruginosa?
What are the adhesins for Pseudomonas aeruginosa? (4)
What is the major exotoxin for Pseudomonas aeruginosa? Function? How is it administered to cells?
Blocks protein synthesis through inhibition of EF-2
Type III secretion system
What is the MOA of abx resistance for Pseudomonas aeruginosa?
Mutation of pore proteins
CF and burn patients hate what bacteria?
What is the common cause of swimmer's ear (otitis externa)?
What are the two major soft tissue infections that Pseudomonas aeruginosa causes?
Pseudomonas aeruginosa infections are associated with what type of skin problem?
Bacteremia caused by Pseudomonas aeruginosa causes what?
What is Ecthyma gangrenosum?
Necrotic skin lesions and infections of the blood vessels
What predisposes burns to Pseudomonas aeruginosa?
Moist surface + inability of PMNs to penetrate skin
What is Hot tub skin rash? Symptoms?
Pruritic erythematous papules x5 days
What is the cause of "green nails"?
Pseudomonas aeruginosa biofilm/infection of the paronychia
What is webspace intertrigo? Cause?
Macerated and eroded skin on interdigital toes, usually caused by Pseudomonas aeruginosa
What is the treatment for Pseudomonas aeruginosa infections?
Combination therapy with aminoglycosides
What is the function of LTA that strep produces?
Involved in adhering to fibronectin on epithelial cell surfaces
What is the function of proteins F and M on strep?
F = adhesion
M = blocks C3b
What is the MOA of the superantigens produced by strep?
Increase proinflammatory cytokines
What is the function of DNAase that strep produces?
Depolymerizes DNA in pus, decreasing viscosity
What is the function of streptokinase produced by strep?
Sharply demarcated erythema, with associated fever and chills = ?
What is the pathogenesis of necrotizing fasciitis?
Dead tissue blocks circulation to the wound creating heaven for bacteria
What is the pathogeneis of rhemuatic fever heart damage?
Strep Pyogenes m M protein looks like heart tissue
Gram positive cocci in clusters = ? (usually)
Gram positive cocci in chain = ? (usually)
What are the symptoms of rheumatic fever? How long after a pharyngeal infx?
Diffuse, erythematous rash on upper chest, then extremities
Coating of the tongue (strawberry)
3 week post GAS pharyngitis
How do you distinguish between strep and staph toxic shock syndrome?
Staph = intoxication
Strep = bacteremia
Antibodies against streptolysin O (ASO test) is useful for confirming what disease(s)?
Rheumatic fever or glomerulonephritis
Can cutaneous infections of strep cause acute rheumatic fever?