Cocci pt 1 Flashcards
What are the three most common disease causing Cocci?
- Staphylococcus
- Streptococcus
- Nisseriae
What are the common factors of the staphylococcus family?
- Oxygen requirements, gram typing, environmental
Gram +
Typically in clusters
Facultative anaerobes
Very resistant to environment
Where are Staph aureus typically found?
Found on 60% of humans
-colonized at birth
What are the types of enzymes that Staph Aureus have:
- Coagulase
- Penicillinase
- Hyaluronidase
- Staphylokinase
- Lipase
What do these enzymes do:
- Coagulase
- Penicillinase
- Coagulase= Clots blood plasma
- Penicillinase= Destroy penicillin antibiotic
What do these enzymes do:
- Hyaluronidase
- Staphylokinase
Hyaluronidase= Digests connective tissue
Staphylokinase= Digests blood clots
What does this enzyme do:
Lipase
Lipase= Digests skin oil to help colonize
What types of toxins do Staphylococcus aureus produce:
- Hemolysins
- Leukocidin
- Enterotoxin
- Exfolative
- Toxic shock toxin
What do these toxins do:
- Hemolysins
- Leukocidin
Hemolysins= Lyse blood cells
Leukocidin= Destroys neutrophils/macrophages
What do these toxins do:
Enterotoxin
Exfolative
Enterotoxin= Disrupts GI system
Exfolative= Detaches dermis/epidermis
What does this enzyme do:
Toxic shock toxin
Causes fever, rash, vomiting
What type of infections do staphylococcus aureus cause:
- Cutaneous
- Osteomyelitis
- Respiratory
- Bacteremia
- Fixed toxemia
- Scalded Skin syndrome
What do these infections invade:
- Cutaneous
- Osteomyelitis
- Cutaneous= Wounds, follicles, and glands
- Osteomyelitis= Systemic bone infection (bone necrosis)
How does the Staph species cause this infection?
Respiratory
Symptoms?
Naturally found in nose:
Goes into lungs and causes pneumonia/lung abcess
How does the Staph species cause this infection?
Bacteriemia (what does it infect?)
Escapes from skin infection/device
Goes to bloodstream, liver/kidneys/heart/brain
How does the Staph species cause this infection?
Fixed toxemia
Symptoms?
Makes toxin in food
Nausea, vomiting, diarrhea
How does the Staph species cause this infection?
Scalded skin syndrom
Symptoms?
Releases exofoliative toxin
Bright red skin, blisters, peeling
How does the Staph species cause this infection?
Toxic shock syndrome
Symptoms
Releases superantigen that causes massive response by T-cells
Fever, low BP, renal failure
What are the ways that the immune system counters Staph aureus?
- Macrophages and neutrophils
- Cell mediated immunity forms abcesses to contain
What are treatments for:
- Staph Aureus
- MRSA
Staph aureus= Sulfa drugs (tetracycline)
MRSA= Vancomysin
How do staph/strep species react to a catalase test?
Staph= positive
Strep= negative
How do staph species react to a coagulase test?
S. aureus= positive
All others= negative
How do staph species react to anaerobic growth?
S. hominis= won’t grow
All others= will grow
How do staph species react to Urease production?
S. capitis= does not produce
All others= do produce
How do the Staph species react to Mannose fermentation?
S. epidermidis= ferments
All others= do not
