Cleaning, disinfection and sterilisation

• Cleaning is a process that physically removes contamination by foreign material and organic material e.g. by using warm water and detergent
• Disinfection is a process to kill or remove most, but not all, viable microorganisms
• Sterilisation is a process to kill all viable microorganisms (including bacterial spores but excluding prions)
• Prions are most resistant to decontamination (e.g. Creutzfeldt-Jakob Disease). Lipid or medium-sized viruses (e.g. HIV, herpes, hepatitis B) are most susceptible to decontamination
• In 2016, 6.9% of patients had a healthcare associated infection. HAIs cost the NHS an estimated £2.1 billion in 2016/17. HAIs are a driver of antimicrobial resistance
• Common types of healthcare associated infection: pneumonia, UTIs, surgical site, GI tract, bloodstream
• E. coli, staphylococci, Klebsiella pneumoniae, Pseudomonas aeruginosa, enterococci, clostridium difficile and Proteus species are common bacterial healthcare associated infections
• Covid, Norovirus, Influenza and RSV are common viral healthcare associated infections
• Candida and aspergillus species are common fungal healthcare associated infections
• Airborne, droplet spread, direct contact, indirect contact and common vehicle are all routes of HAI transmission
• Preventing HAIS in the NHS

  • Hand hygiene
  • Hospital environmental hygiene
  • Principles of asepsis
  • Use of personal protective equipment
  • Safe use and disposal of sharps
• Norovirus

  • diarrhoea and vomiting
  • common
  • expensive and disruptive
  • very infectious
  • PCR testing of stool samples should be readily available
  • Appropriate patient placement (side rooms and cohort nursing)
  • Increased environmental decontamination
  • Use of PPE
  • Handwashing with soap and water
• Hand washing

  • soap and water must be used when hands are visibly soiled or potentially contaminated with body fluids
  • soap and water are preferred when caring for patients with diarrhoea and vomiting
  • ensure hands can be decontaminated effectively
  • with alcohol hand gel the solution must come into contact with all surfaces of the hand, rub vigorously until solution has evaporated and hands are dry
  • Skin care is important
  • Will be audited
  • Don't forget patients and visitors
• Five moments for hand hygiene

  • Before touching a patient
  • Before clean/aseptic procedure
  • After body fluid exposure risk
  • After touching a patient
  • After touching patient surroundings
• Antiseptics kill microorganisms present on skin and mucous membranes (contrast with disinfectants which kills microorganisms on inanimate surfaces)

  Examples: Chlorhexidine, alcohol, iodine, quaternary ammonium compounds

  Uses include - handwashing, pre-operative skin decontamination, mucous membrane disinfection prior to a procedure, preventing and treating infected skin or mucous membranes
• Disinfection

  • Generally done by heat or chemicals
  • Unpredictable and depends on many factors including
  • Concentration
  • Contact time
  • Presence of organic material on surface
  • Nature of surface
  • Type and number of microorganisms
  • Chemical disinfectants include
  • Alcohol
  • Chlorine releasing agents
  • Glutaraldehyde
  • Hydrogen peroxide
  • Also need to consider safety, cost, acceptability, damage to surfaces etc.
• Sterilisation

  • Heat (dry or moist), chemical or radiation
  • Moist heat (steam under pressure) is commonly used - autoclave
  • autoclave example - 121-124 celsius for 15 minutes
  • Chemicals used for heat and moisture sensitive devices
  • Chemicals used include ethylene oxide and hydrogen peroxide
  • Radiation e.g. gamma rays
• Indwelling medical devices

  • Intravascular devices and catheters are a major risk for infection
  • infection may be endogenous
  • the majority of hospital associated bacteraemias and candidaemias are associated with indwelling medical devices
  • care bundles/pathways exist to reduce the risk associated with these devices
  • these include information on insertion and maintenance of devices including required hand hygiene, patient preparation and aseptic technique