Flashcards in Gram positive pathogens (complete) Deck (182)
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1
Are Staphylococcus normal flora
yes, but they can be opportunistic pathogens
2
What are the nine groups of Gram positive pathogens we study
1. Staphylococcus Aureus
2. Streptococcus Pyogenes (A)
3. Streptococcus pneumoniae
4. Bacillus Anthracis
5. Clostridium (perfringins, dificile, tetani, and botulinum)
6. Listeria monocytogenes
7. Corynebacterium diptheriae
8. propionibacterium acnes
9. Actinomyces species
3
Staphylococcus is motile or nonmotile?
non-motile
4
how does Staphylococcus interact with oxygen (anarobe, aerobe)
facultative aerobe
5
What does Staphylococcus look like under a microscope
cocci in irregular clusters (grapes)
6
What is the most common organism found on the skin
Staphylococcus epidermis
7
Where is Staphylococcus aureus typically carried in 30-50% of the healthy population
nose and perineum
8
How can you tell between Staphylococcus aureus and Staphylococcus epidermis
Staphylococcus Areus is
coagulase positive, mannitol positive
Staphylococcus Epidermis
coagulase negative, mannitol negative
9
which is more virulent Staphylococcus Aureus or Staphylococcus epidermis
Staphylococcus Aureus
10
How many bacteria are required for disease to result from a staph infection
only a few hundred bacteria
11
what are the three things about Staphylococcus that cause pathogenicity
1. It's ability to evade phagocytosis
2. Production of enzymes
3. production of toxins
12
What are the three categories of Staphylococcus diseases
Noninvasive disease
Cutaneous disease
Systemic disease
13
What is a non-invasive Staphylococcus disease
food poisoning that results from ingested food contaminated with enterotoxin
14
What are examples of cutaneous Staphylococcus disease
scalded skin syndrome
impetigo
folliculitis
furuncles
15
How does Staphylococcus defend itself against phagocytosis
Protein A
Bound Coagulase:
16
how does Protein A help Staphylococcus defend against phagocytosis
Protein A onthe bacterial surface binds antibodies by the Fc end. This inhibits opsonization and complement
17
how does bound coagulase help Staphylococcus defend against phagocytosis
converts blood protein fibrinogen into fibrin molecules, which make blood clots, the Staphylococcus hides from the phagocytes in the clots
18
What are the 5 enzymes created by Staphylococcus that attribute to its virulence
Cell-free coagulase
hyaluronidase
staphylokinase
lipases
B-lactamase
19
What does Cell-free coagulase do for Staphylococcus
triggers fibrin formation, which helps the Staphylococcus hide from phagocytes
20
What does hyaluronidase do for Staphylococcus
breaks down hyaluronic acid, which allows the bacteria to spread between cells
21
what does staphylokinase do for Staphylococcus
dissolves fibrin threads in blood clots, which allows Staphylococcus aureus to free itself from clots
22
what do lipases do for Staphylococcus
digests lipids, allows Staphylococcus to grow on the skins surface and in oil glands
23
what do B-lactamases do for Staphylococcus
Breaks down penicilins, makes them resistant to beta-lactams
24
What are the 4 toxins produced by Staphylococcus
Cytolytic toxins
exfoliative toxins
Toxic shock syndrome toxins
Enterotoxins
25
What are the two cytolytic toxins created by Staphylococcus and what do they do
alpha-toxins- pore forming toxins
PVL - beta pore forming toxin that lyses leukocytes
26
What do the exfoliative toxins of Staphylococcus cause
they cause the patients skin cells to separate from each other and slough off the body
27
What does the toxic shock syndrome toxin of Staphylococcus cause
it causes toxic shock syndrome, which is caused by the creation of a superantigen
28
What do enterotoxins of Staphylococcus cause
they stimulate intestinal muscle crampings, naseua, and intense vomiting (staph food poisoning)
29
Does Staphylococcus aureus cause food poisoning
yes
30
