Bacterial Infections in Vesicles, Bullae, Pustules

Question 1

Staphylococcus aureus

Answer 1

• Gr+ cocci, often *clusters
• Ubiquitous
• Normal microbiota
   o *S. aureus, anterior nares, skin, mucous membranes
   o Sometimes throat, perineum, vagina
• Nonmotile, nonendosporeforming
• Facultative anaerobes
• *Catalase +
• *B hemolysis
• *Coagulase +
• *mannitol +
VIRULENCE**ALL
• Capsule (Polysaccharide)
• Loose slime layer
• CoNS
• Monosaccharides, proteins
• Protein A
• PVL
• Fibronectin-binding protein
• superantigens
DISEASE
• Folliculitis, furunculosis, carbunculosis, skin abscess
   o Note Pseudomonas aeruginosa folliculitis
• Impetigo
   o Staphylococcus aureus, Streptococcus pyogenes or both
• Staphylococcal scalded skin syndrome (SSSS)

Question 2

Streptococcus pyogenes

Answer 2

DISEASE
• Erysipelas (a form of cellulitis)
o Mostly Streptococcus pyogenes