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
What does the lipases enzyme do?
It digests lipids, and allows Staph to grow on skin and in oil glands
What does the Beta-lactamase enzyme do?
It breaks down penicillin and allows bacteria to survive treatment with Beta-lactam antimicrobial drugs
What toxins are produced by Staph aureus to avoid phagocytosis?
Cytolytic, Exfoliative, Toxic-Shock 1&2, Enteritoxins toxins
What do cytolytic toxins do?
They disrupt the cytoplasmic membrane of a variety of cells
What do Exfoliative toxins do?
They cause skin cells to slough off
What do Toxic Shock syndrome toxins 1&2 do?
They cause toxic-shock syndrome
What do enterotoxins do?
Stimulate symptoms associated with food poisoning
What kind diseases do Staph aureus invoke?
Noninvasive, Systemic, and Cutaneous diseases
What noninvasive diseases is produced by Staph aureus?
Bacteria that produce enteritoxins on food, food poisoning (intoxication)
What Cutaneous disease is invoked by Staph aureus?
Various skin conditions, scalded skin syndrome, impetigo, and folliculitis
What Systemic disease is caused by Staph aureus?
Toxic shock syndrome, Bacterimia, Endocarditis, Pneumonia, and Osteomyelitis
What is TSS?
Staph aureus toxin is absorbed into the blood, produces fever, vomiting, rash, and low blood pressure caused by tampons
Bacterimia
Presence of bacteria in the blood
Endocarditis
Damage to the lining of the heart
Pneumonia
Inflammation of the lungs, Empynema occurs when pus fills the lungs,
Osteomyelitis
Inflammation of the bone marrow and bone
How does Strep pyogenes evade phagocytosis through the M protein?
It destabilizes the complement
How does Strep pyogenes evade phagocytosis through the Hyaluronic acid capsule?
It hides bacteria from leukocytes
How does Strep pyogenes evade phagocytosis through the Streptokinase enzyme?
It breaks down blood clots and helps strep spread through tissues.
How does the C5a peptidase produced by Staph pyogenes help evade phagocytosis?
C5a peptidase breaks down complement protein C5a
How does the pyogenic toxin help Staph pyogenes evade phagocytosis?
Can stimulate fever, rash, and shock
How does the Streptolysins toxin help Staph pyogenes evade phagocytosis?
The lyse of red blood cells
What streptococcal diseases does Strep pyogenes cause?
Pharyngitis, Scarlet fever, Pyoderma and erysipelas, Necrotizing fasciitis (flesh eating disease), Strep tss
