VIRULENCE FACTOR (STAPHYLOCOCCI) Flashcards
A heme enzyme that catalyzes the decomposition of H2O2 to water and oxygen:
catalase
Differentiates (+) Staphylococci & (+) Micrococci from Streptococci (-):
catalase
Reagent of catalase test:
hydrogen peroxide
(+) result of catalase test:
bubble formation/ effervescence
Aerobic catalase test:
3% H2O2
Anaerobic catalase test:
15% H2O2
Superoxidase test:
30% H2O2
Causes pseudo-catalase reaction:
bubbles = need oxygen = AER
Aerococcus
Enterococcus
Rothia
Coagulates the fibrinogen in plasma:
coagulase
Promotes the formation of a fibrin layer therefore protecting the bacteria from phagocytosis:
coagulase
Major virulence factor of S. aureus:
coagulase
Coagulase bound to the cell wall:
cell-bound coagulase/clumping factor
Cell-bound coagulase:
it causes bacterial cell to agglutinate in plasma
Coagulase free from the cell wall:
unbound coagulase/free factor
Unbound coagulase:
it causes clot formation when bacterial cells are incubated with plasma
It enhances invasion and survival in tissues; breaks down hyaluronic acid resulting to spread of bacteria:
hyaluronidase
Other names of hyaluronidase:
spreading-factor enzyme, Duran-Reynold factor
It dissolves fibrin clot:
staphylokinase
Other names of staphylokinase:
fibrinolysin
Essential for the survival in sebaceous areas of the body:
lipase
It is important for the formation of furuncles, carbuncles and boils:
lipase
Other names of lipase:
fat-splitting enzyme
Increases organisms mobility:
deoxyribonuclease (DNAse) and phosphatase
Breaks down penicillin and other beta-lactam drugs:
beta-lactamase
Acts as neurotoxins that stimulate the vagus nerve to cause vomiting:
enterotoxin
Resistant to hydrolysis by the gastric and intestinal enzymes:
enterotoxin
True or False:
Reheating contaminated food will not prevent the disease.
TRUE. It is stable to heating at 100C for 30 minutes. They also do not cause any detectable odor or change in appearance or taste to food.
Most common enterotoxin:
enterotoxin A (78%)
Responsible for food poisoning (the infected food handler is the source of contamination):
enterotoxin A, B, and D
Associated with pseudomembranous enterocolitis:
enterotoxin B
Causes enterocolitis:
enterotoxin B, C, G, and I
Is a pore-forming exotoxin that kills WBC; it suppresses phagocytosis:
leukocidin/panton-valentine leukocidin
Responsible for necrotizing skin and soft tissue infections:
PVL
PVL causes:
community-acquired MRSA
It causes anemia- making iron available for microbial growth:
hemolysin
Disrupts smooth muscle in blood vessels; toxic to RBCs, WBCs, hepatocytes, platelets:
alpha hemolysin
Alpha hemolysin is exhibited by:
S. aureus
Catalyzes the hydrolysis of membrane phospholipids resulting in cell lysis:
beta hemolysin
It destroys sphingomyelin:
beta hemolysin
Other names of beta hemolysin:
hot-cold lysin, sphingomyelinase C
Cytolytic to RBCs and demonstrates nonspecific membrane
toxicity to other mammalian cells:
delta hemolysin
Delta hemolysin is exhibited by:
S. aureus, S. epidermidis, S. hemolyticus
Responsible for the various skin, wound, and deep tissue
infections:
gamma hemolysin
Gamma hemolysin is exhibited by:
S. aureus
Associated with PVL:
gamma hemolysin
It causes the epidermal layer of the skin to slough off:
exfoliating toxin A and B
It causes SSS or Ritter disease:
exfoliating toxin A and B
Other names of Exfoliating toxin:
epidermolytic toxin
A chromosomal-mediated toxin:
TSST-1
Causes menstruating-associated TSS:
TSST-1
Other names of TSST-1:
enterotoxin F, pyogenic exototxin C
Immunologically active substance found in the cell wall:
protein A
Antiphagocytic by competing with neutrophils for the fc portion of specific opsonin:
protein A
Appear as a slime layer/biofilm; inhibits phagocytosis:
capsule
Activates complement, IL-1, and act as a chemotactic factor for the recruitment of PMNs:
peptidoglycan
