Staphlococci

S. aureus

• 20-60% colonisation - colonises skin and mucous membranes
• Coagulase positive - appear golden
• Multiple conditions/presentations indicates incredible genetic flexibility and multiple strains of S. aureus
  • MSSA - treatable with antibiotics
  • MRSA - specific resistant (to flucloxicilin) strain associated with hospitals
  • Nasal strain can protect by excluding aggressive strain

S. epidermis

• 100% colonisation - skin and mucous membranes
• Coagulase negative
• Associated with nosocomial infection/immunocompromised
  • Associated with foreign devices e.g. catheters, prothetic valve infective endocarditis

S. aureus virulence factors

• Virulence and virulence factors: the molecular/genetic basis of pathogenesis that characterises species, subspecies and strains
  • Emerge through mutations and horizontal gene transfer
  • Virulence factors result in disease caused by specific component of pathogen e.g. toxic shock

Toxinoses

• Discrete disease associated with single protein component, a toxin or exotoxin (not the endotoxin)
• TSST-1: superantigen which is the commonest cause of toxic shock
• Staphlococcal food poisoning: (enterotoxin SeA SeB and SeC) intoxication, 1-5 hrs, vomiting, diarrhoea
• SSS: (scalded skin syndrome) exfoliation toxins, often neonatal face, axilla and goin, ETA and ETB toxins target DG-1

Toxic shock syndrome

• Linked to tampon use
• Rapid progression (48 hrs)
• High fever, vomiting, diarrhoea, sore throat, muscle pain