Exam 4 Chapter 19 Gram-Positive Cocci Flashcards
What is the physiology of the Staph family?
They are facultative anaerobes, they grow in grape-like clusters, Salt tolerant, non-motile and non flagellated, tolerant of desiccation and heat
What is the broad idea of Staph aureus?
More virulent strain, Variety of conditions depending on site of infection
What is the broad idea of Staph epidermidis
Normal microbiota of human skin, Opportunistic infections
Where is Staph aureus found on the skin?
In moist skin folds
Where is Staph epidermidis found on the skin?
It is ubiquitous on the human skin
Where can both of the Staph species grow if introduced?
Can grow in the gastrointestinal, upper respiratory, and urogenital tract
What can prevent Staph infections?
Hand washing and aseptic techniques prevents infections
What are Staph aureus’ pathogenic structural defenses?
Protein A, Bound coagulase, and Polysacharide slime layers (capsule)
Protein A is?
Coats to the cell surface, binds to the IgG antibody, inhibiting the complement cascade and the opsonization.
Bound coagulase is?
The convergence of fibrogen into fibrin molecules to then clot to hide the bacteria from phagocytic cells
Polysaccharide slime layer (capsules)
Facilitate attachment to surfaces, inhibits leukocyte chemotaxis and phagocytosis
What enzymes are secreted by Staph aureus to avoid phagocytosis?
Cell-free coagulase, Hyaluronidase, Staphylokinase, Lipases, and Beta-lactamase
What does the Cell-free coagulase enzyme do?
Triggers blood clotting
What does the Hyaluronidase enzyme do?
Breaks down hyaluronic acid (the bond between cells) in the skin to enable bacteria to spread between the cells.
What does the Staphylokinase enzyme do?
Dissolves the fibrin threads in blood clots, allowing Staph aureus to free itself from the clots
