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Lists the categories of micro-organism that cause infection.

  • Bacteria
  • Viruses
  • Fungi
  • Parasites
  • Prions


List the common sterile sites in the body

  • Blood
  • CSF(cerebro-spinal fluid)
  • Lung
  • Bladder


List the non-sterile sites in the body

  • Skin
  • Nasopharynx
  • Urethra (a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body.)
  • Gut


Outline the role of microscopy in bacterial infection.

  • Light microscopy (x1000 magnification)
  • Unstained - to see pus cells (e.g.urine, CSF)

                     - to see parasites (faeces)

  • Gram stain - to see bacteria and yeasts/fungi
  • Viruses not visible in light microscope


Explain the difference between sterile and non sterile sites.

  • Sterile sites should contain no micro-organisms 
  • Non-sterile sites may contain commensal microbes that may not harm the body, but still show up in microscopy or cultures.


Outline the methods of detecting viruses

  • Molecular methods-real time PCR
  • Antigen detection
  • Serology to determine immunity (antibodies in serum)
  • Used rarely: Electron microscopy/ Cell or tissue culture - inoculate a “cell line"


Outline the diagnostic principles in parasitology

  • Microscopy of different stages: parasites, cysts and ova in faeces.
  • Blood films for malaria
  • Culture rarely possible
  • Serology sometimes useful


Describe basic infection control measures 

  • Wash hands before touching patient
  • Wash hands or apply alcohol gel between patients
  • Swab stethoscope between patients
  • Patients isolated in single room (“barrier nursed” or source isolation) have extra precautions:
  1. Wash hands, wear plastic apron
  2. On leaving, dispose of apron, wash hands


List the common specimen types collected for culture.

  • Urinary tract infection - mid-stream urine (MSU)
  • Chest infection – sputum
  • Tonsillitis/pharyngitis – throat swab
  • Wound or site of infection - swab or pus (swabs are sent in bacterial transport medium)
  • Diarrhoea - faeces
  • Bacteraemia - blood culture
  • Meningitis - cerebro-spinal fluid (CSF)


Feutures of gram stain & Microscopy

  • Rapid 
  • Not sensitive
  • Can’t usually identify particular species


Features of cell culture

  • Slow
  • Sensitive
  • Culture conditions suitable for the expected species


4 Healthcare Acquired Infection

  1. Methicillin Resistant Staph aureus (MRSA)
  2. Clostridium difficile
  3. Organisms with Extended Spectrum β-lactamases (ESBLs)
  4. Noroviruses