Week 6 Flashcards
97% of Staphylococcus aureus isolated in human produce the enzyme
Coagulase
enzyme that reacts with the blood factor in the plasma to initiate clot formation
Coagulase
enhance the deposition of the fibrin around the organism to protect them from phagocytosis
counteracts the action of fatty substances secreted by the body
Lipase
help in the colonization of organism – oily skin surfaces
Lipase
found in the intracellular ground substance of connective tissue
Hyaluronidase
promote invasion of organism by digesting the intracellular ground substance “glue” (hyaluronic acid) that binds connective tissue in host tissue
Hyaluronidase
proteolytic enzyme with fibrinolytic activity
Staphylokinase
causes dissolution of clot – spread infection further
Staphylokinase
enzymatically and antigenically distinct from Streptokinase of Streptococci
Staphylokinase
Production by most strain of Staphylococcus
Staphylokinase
degrade nucleic acid DNA
Nuclease (DNAse)
most specific test for Staphylococcus aureus
Nuclease (DNAse)
found in cell surfaces of 90% - 96% of Staphylococcus aureus
Nuclease (DNAse)
lyse RBC by destroying their membrane
Hemolysins/Cytolytic Toxins
producing tissue damage;
Hemolysins/Cytolytic Toxins
abscess formation
Hemolysins/Cytolytic Toxins
Chromosomal mediated
Hemolysins/Cytolytic Toxins
A heterogenous protein that acts on a broad spectrum of eukaryotic cell membranes.
A Hemolysin
Degrades sphingomyelin, and is therefore toxic for many kinds of cells including human red blood cells
B toxin
most powerful toxin that lyses RBC of various animals (platelets and macrophages= tissue damage)
A-hemolysis
produce hemolysis in blood agar medium
A hemolysis
Predominant hemolysin produced by S. aureus
A-hemolysin
Heat labile
B toxin
heterogenous and dissociates into subunits in non – ionic detergents.
8 Toxin
Disrupts biologic membranes and may have a role in Staphylococcus aureus diarrheal diseases.
8 toxin
Active against macrophages, lymphocytes, and neutrophil.
8 toxin
A leukocidin that lyses white blood cells.
Y toxin
Composed of two proteins designated S and F which may interact with the two proteins of Panton – Valentine Leukocidin.
Y Toxin
composed of two (2) protein components that can kills white blood cells of humans and incapacitate the phagocytic line of the defense of the host. (cause pore formation in the cellular membrane necrosis and severe inflammation)
Panton – Valentine Leukocidin
An important virulence factor in CA – MRSA infections.
Panton – Valentine Leukocidin
Encoded on a mobile phage
Panton – Valentine Leukocidin
stable and resistant to the action of gut enzymes
Heat
Produce when Staphylococcus aureus grows in carbohydrate and protein foods.
Enterotoxins
Most often EXCRETED from the cell; but some accumulate inside the cell are either injected directly or are released by cell lysis.
Enterotoxins
Types of enterotoxins:
most frequently associated with Staphylococcus food poisoning
A & D
Types of enterotoxins:
associated with hospital acquired infection
(nosocomial); ingestion of 25μg results in
vomiting and diarrhea (pseudomembranous enterocolitis- milk product)
B
Types of enterotoxins:
Recently recognize toxin, associated with toxic shock syndrome
F
2 types of Exfoliative Toxins
Exfoliative Toxin A & Exfoliative Toxin B
