Healthcare associated infection

• •Endogenous Infection = Infection occurs from within the patient
• •Exogenous Infection = Infection which originates from outside of the body
• S.aureus characteristics:

  • Gram positive cocci
  • Grow in 18oC - 40oC
  • Facultative anaerobes.
  • Catalase positive
  • Beta haemolytic on blood agar
  • S.aureus was named after its golden colour on blood agar.
• S.aureus infection:

  • COLONISE: With the use of MSCRAMMS = Microbial Surface Components Recognising Adhesive Matrix Molecules
  • EVADE: Protein A binds the IgG antibody upside down.
  • Damage: Uses invasins and exotoxins. E.g. Toxic Shock Syndrome Toxin 1 (TSST-1)
• Methicillin is a beta-lactam antibiotic used against beta-lactamase producing S.aureus.-> MRSA is resistant to methicilin
• •MecA (30-50kb) incorporated on encodes for additional penicillin binding protein (PBP2a); reduced affinity for beta-lactams

  •MRSA resistant to all beta-lactam antibiotics
• E.coli characteristics:

  • Gram negative bacilli
  • Facultative anaerobes
  • Catalase positive
  • Peritrichous flagella
  • Beta haemolytic on blood agar
• Gastrointestinal tract infection:

  Caused by c.difficle

  • gram posistive
  • Anaerobic
  • Spore forming
  • Non-haemalytic on blood agar.
  • Appears glossy and grey coloured
• • C.diff screening occurs after a patient tests positive, the whole ward is then screened.
  • Molecular methods are used to detect the presence of toxins A and B.
  • Machines, like the Cepheid, provide rapid detection and 2 hours turn around time.
  • Patients will be moved wards depending on their result.