Staphylococci Flashcards
What are the identifiable features of S. aureus?
Gram-positive, catalase-positive cocci in clusters
Is S. Aureus coagulase positive or negative?
Coagulase positive
What are the common soft tissue infections caused by S. aureus?
Impetigo
Cellulitis
Boil
Carbuncle
Folliculitis
What are the 4 toxins produced by S. aureus?
Alpha toxin
Enterotoxin
Toxic Shock Syndrome Toxin-1
Epidermolytic toxin
How does TSST-1 cause staphylococcus toxic shock syndrome?
Causes non-specific binding of MHC class II to T cell receptors, activating polyclonal T-cells which induce a cytokine storm
What are the 4 common deep infections caused by S. aureus?
- Endocarditis
- Osteomyelitis/septic arthritis
- Pneumonia following influenza
- Abscess in any tissue
What disease does the epidermolytic toxin cause?
Scalded Skin Syndrome
What does the S. aureus enterotoxin do?
Causes food poisoning within a few hours if the toxin is pre-formed
What antibiotic should be used to manage a suspected S. aureus infection empirically?
Vancomycin to cover for MRSA infection
How are S. saphrophyticus, S. epidermidis and S. lugdenensis distinguishable from S. aureus?
Coagulase negative
What is S. saphrophyticus commonly associated with?
UTI in sexually active females
What is S. lugdenensis commonly associated with?
Endocarditis
What is S. epidermidis commonly associated with?
Infections of orthopaedic implants or hardware
What are the 3 bacteria that most commonly cause post-influenza pneumoniae?
S. pyogenes
S. aureus
S. pneumoniae
S. aureus gram-positive cocci in chains or clusters?
Clusters
