PRELIM 08 - Gram-Positive Cocci Flashcards
Gram-positive spherical cells arranged in grapelike irregular clusters
Staphylococci
Staphylococci produces __________, which converts H2O2 to H2O and O2
Catalase
2 Staphylococcus aureus enzymes
Coagulase, Clumping factor
An S. aureus enzyme that clots oxalated or citrated plasma
Coagulase
An S. aureus enzyme that adheres organism to fibrinogen and fibrin
Clumping factor
4 Staphylococcus aureus toxins
Hemolysins, Exfoliative toxins, Toxic shock syndrome toxin-1 (TSST-1), Enterotoxins
An S. aureus toxin that lyse many cells and creates pores that cause release of inflammatory mediators
Hemolysins
An S. aureus toxin that is a superantigen; produces the generalized desquamation of staphylococcal scaled skin syndrome
Exfoliative toxins
An S. aureus toxin that is a superantigen and binds to MHC-II molecules which promotes the manifestations of toxic shock syndrome
Toxic shock syndrome toxin-1 (TSST-1)
An S. aureus toxin that is heat stable, resistant to gut enzymes, and causes food poisoning
Enterotoxins
6 S. aureus clinical findings
Furuncle/Carbuncle, Impetigo/Pyoderma, Bacteremia, Food poisoning, Toxic shock syndrome, Scalded syndrome
Localized abscess (S. aureus clinical findings)
Furuncle/Carbuncle
Local infection of superficial layers of skin, especially in children (S. aureus clinical findings)
Impetigo/Pyoderma
Supparation (abscess) occurs in other parts causing endocarditis, osteomyelitis, meningitis, and pneumonia (S. aureus clinical findings)
Bacteremia
Supparation in blood vessels of the metaphysis of a long bone
Osteomyelitis
Its incubation period is 1-8 hours; symptoms include N/V, diarrhea, and fever (S. aureus clinical findings)
Food poisoning
Abrupt onset of high fever, vomiting, diarrhea, myalgia, scarlatiniform rash, and hypotension with cardiac and renal failure in most severe cases (S. aureus clinical findings)
Toxic shock syndrome
Its symptoms include redness and tenderness of the central face, neck, trunk, and intertriginous zones
Scalded skin syndrome
Hydrolyzes β-lactam antibiotics; give β-lactamase resistant penicillins
β-lactamase
Resistance to β-lactamase resistant penicillins due to low affinity PBPs; give vancomycin
mecA gene
Bacteria that causes 75% of coagulase-negative staphylococcal infections
Streptococcus epidermidis
Bacteria that is part of the normal flora of the skin, respiratory tract, and GIT; relatively common cause of UTIs in young women
Streptococcus saprophyticus
Gram-positive spherical cells arranged in pairs or chains
Streptococci
Grouping based on Lancefield antigens (carbohydrates) present in the cell wall
Lancefield grouping
N-acetylglucosamine (Lancefield group)
Group A