Staphylococcus
What are staph. aureus's virulence factors (4)
adhesins, toxins, capsule, protein A
What is sepsis
systemic inflammation of blood following bacteremia
Steps/general mechanism of microbial pathogenicity (6)
1. system entry 2. tissue attachment 3. tissue invasion 4. tissue colonization 5. secretion of toxins/virulence factors 6. evasion of host response
What is S. saprophyticus resistant to
Novobiocin
What will Mannitol Salt agar select for: S. aureus or epidermidis
S. aureus
What can the Mannitol Salt Agar plate distinguish
S. aureus and epidermidis
What does the coagulase test differentiate between
S. aureus and epidermidis
Why is there a color difference on a MSA with S. aureus and S. epidermidis
S. aureus has genes for the breakdown of mannitol
Coagulase negative Staphylococcus
S. epidermidis, saprohyticus
Where is S. epidermidis commensally found
Skin
Staphylococcus species with medial importance (3)
Staph. aureus, epidermidis, saprophyticus
What does the catalase test differentiate between
Staphylococcus and streptococcus
What infections can s. epidermidis cause
Stitch abscesses, indwelling med devices,
What infections can S. saprophyticus
UTIs
What makes up SCCmec
att and mecA
How does staph. aureus interact with Abs? What is the result of this interaction
binds to Fc region via Protein A. blocks initiation of phagocytosis
What does mecA do
binds to PBP to inhibit activity by penicilin
Why is bacteremia by staph. aureus dangerous
blood has high nutrients - iron, glucose, amino acids, minerals, etc.
Where is S. saprophyticus commensally found
female genital tract, perineum
How does staph. aureus become methicillin resistant
integration of a genetic element from a bacteriophage
Where does staph. aureus exist normally/commensally
nasal passages, skin
Catalase result for streptococcus
negative
Coagulase result for S. epidermidis
negative
What diseases can staph. aureus cause
pneumonia, meningitis, food poisoning, TSS, bacteremia, necrotizing pneumonia, endocarditis, osteomyelitis
Catalase result for S. aureus
positive
Coagulase result for S. aureus
positive
What effect does staphylokinase have in the blood
promotes coagulation
What is staph. aureus an etiological agent of
skin and soft tissue infections (SSTI's)
What is a virulence factor
structural/secreted microbial molecule that is absolutely necessary for the establishment of infection in an animal/human
Damaging oxygen radicals
superoxide, hydrogen peroxide, NO
Color of S. epidermidis
white
What color is staphylococcus aureus
yellow