Staphylococcus aureus

• Greek staphylé = "bunch of grapes"

Laboratory identification

• Gram positive cocci
• catalase positive
  • produces bubbles from hydrogen peroxide
  • differentiates from Streptococcus species
• coagulase positive
  • differentiates from all other Staphylococcus species
• aerobic / facultative anaerobic

Features

• Capsule (slime layer)
  • protects from phagocytosis
• Protein A
  • binds Fc
  • consumes complement and prevents immune clearance

Toxins

• alpha, beta, gamma, delta
• exfoliative toxins (scalded skin syndrome)
• enterotoxins (food poisoning)
• Toxic shock syndrome toxin-1

Live on

• skin
• mucous membranes
• humans, mammals, birds

Diseases

• Scalded skin syndrome
• Staphylococcal food poisoning ( Intoxications)
• Toxic shock syndrome
• Skin Infections
• Bacteraemia (Septicaemia)
• Endocarditis
• Pneumonia
• Empyema
• Osteomyelitis
• Septic arthritis

Also

• Breast Abscess
• Hospital acquired infection
• Neurological infections- traumatic
• Infection in the compromised patient
• Urinary Tract Infections

Methicillin-Resistant Staphylococcus Aureus (MRSA)