Staphylococci Flashcards
The only one that is Coagulase +
S. Aureus
CNS
S. Epidermis
S. Saprophyticus
Capsule
Helps in
Adherence
Inhibiting chemotaxis, phagocytosis
Imp for coagulase negative strains
Enzymes
Lipase
Hyluronidase
Location of methicillin resistance gene
MecA gene on staphylococcal cassette chromosome (SCCmec)
Protein A
S. Aureus
Covalently linked with peptidoglycan layer
Binds Fc portion of IgG
Opsonization and phagocytosis (protection)
Coagulase
Clumping factor
Fibrinogen to fibrin
Protects bacteria under fibrin mash
Staph toxins that are Superantigens
Exfoliative toxin A
Enterotoxins
TSST-1
Panton Valentine leukocidin
Makes s. Aureus more resistant to phagocytosis
Agains PMN and Macs
MRSA –> airway bleeding , erythroderma, leucopenia
Ritter’s Disease
Staph scalded skin syndrome
Positive Nikolsky’s sign
Entire body
Nikolsky’s sign
Large blister with clear fluid
What does exofoliative toxin destroy
Intracellular connections in the skin
Bullous impetigo
Localized staph scalded skin syndrome
No Nikolsky’s sign
Highly communicable
Culture positive
Pustular impetigo
Pus filled vesicles
Crusted lesions
S. Aureus or SA + GAS
TSS
Cutaneous and soft tissue involvement
Tampons
Food poisoning
Enterotoxin
Mean incubation - 4 hrs. Lasts 24 hrs Severe vomiting Cramps, nause Non bloody diarrhea No fever
S. aureus infections
Aspiration pneumonia Osteomyelitis Infective arthritis Acute endocarditis Bacteremia + sepsis Empyema
Why is killing Staph difficult after phagocytic engulfment
They produce carotenoids and catalase – neutralize singlet oxygen and superoxide
S. Epidermidis
Virulence factor and explain what it is
Glycocalyx: the exopolysaccharide slime. Helps in adhesion, antiphagocytic and makes it resistance to antibiotics
S. Saparophyticus
Virulence related to binding to epithelium
UTI
- dysuria
- pyuria
- organisms in urine
What test differentiates between staphylococci from streptococci?
Catalase test is + in staphylococci
The only one with Protein A
S. Aureus
