Wk 1 Bacterial Skin Infections Flashcards
Which bacteria type is most common on the normal human skin microbiome?
gram –
Acne:
- structure association
- what is trapped
- offending organism
- hair follicles
- sebum (from sebaceous glands)
- propionibacterium causes inflammation
Ruptured lesion
pustule on surface
Two possible offending organisms of impetigo infection
Staphylococcus aureus
Streptococcus pyogenes
S. aureus diagnostic method
Gram + cocci
Catalase + (hydrogen peroxide degradation)
Coagulase +
S. pyogenes diagnostic method
Gram + cocci
Catalase -
Streptococcus pyogenes can spread to other areas of the body causing ______________ but is not the strain that can cause ______________
CAN cause glomerulonephritis
CANNOT cause rheumatic fever
Which organism contains the protein A exotoxin?
S. aureus
Protein A function
binds Fc region of IgG and prevents phagocytosis, complement binding, etc.
S. aureus virulence factors
- protein A
- hemolysins and leukolysins
- coagulase
Catalase test principles
Place organism in hydrogen peroxide solution
If catalase present, forms oxygen and bubbles evident
S. aureus = catalase +
S. pyogenes = catalase -
Coagulase test principles
Place organism in solution containing fibrinogen
Coagulation occurs in coagulase + organisms
Novobiocin sensitivity test principles
DNA gyrase inhibitor
sensitive = Staphylococcus epidermidis
resistant = Staphylococcus saprophyticus
Cellulitis: most common offending organisms
S. aureus
S. pyogenes
SSSS infection
- What does it stand for?
- What organism?
- What exotoxins mediate infection?
- Staphylococcal Scalded Skin Syndrome
- Staphylococcus aureus
- ET-A and ET-B
