Safety

Biological Safety

• Universal precautions: first guidelines, centered around blood-borne pathogen precautions
• Body substance isolation (BSI): updated guidelines for protection against all bodily fluids that may potentially transmit disease, as well as additional protection against certain diseases (e.g., airborne disease)
• Routine practises and additional precautions (standard precautions):
  • Assumption that all patients may possibly be infectious even without symptoms
  • Routine use of PPE and practises (e.g., handwashing) to prevent the spread of disease
  • If there are specific infection control concerns, then additional precautions may be used
    • Contact
    • Droplet
    • Airborne

S

• Sterilization: kills all microbes, including spores and cysts
• Disinfection: process that kills many organisms, but not necessary all organisms, especially resistant forms like spores
  • High level disinfection: complete elimination of all organisms on a device, except for small numbers of bacterial spores
• 1% sodium hypochlorite for spot cleaning
• 10% sodium hypochlorite for disinfecting spills
• 2% glutaraldehyde is high level disinfectant

Sterilization

• Dry heat sterilization using only heat (oxidation kills organisms)
• Useful for oils, powders, and solid materials
• 160C for 60min or 170C for 30min
• Spore test using Bacillus subtilus

• Moist Heat autoclave (coagulate and denature proteins)
  • 121C @ 15 psi for 15-30min
  • Useful for wide variety of materials, including liquids (won't evaporate)
    • Avoid oils and powders (repel moisture)
    • Blood and serum will lyse/coagulate
    • Spore test using Geobacillus stearothermophilus
• UV Sterilization
  • 265nm to damage DNA
  • Does not penetrate
• Ionizing radiation
  • Cobalt-60
• Gas Sterilization
  • Ethylene oxide (alkylating agent - blocks metabolism)
  • Requires longer exposure (1-6 hours)
  • Useful for larger or sensitize items

Sterilization Controls

• Autoclave: Geobacillus stearothermophilus
• ETO and dry heat: Bacillus subtilis
• Spore strips: clear broth = inactivated, turbid broth = growth
• Chemical indicators (e.g., autoclave tape) that changes colour if correct temperature is reached

Air Filtration

• HEPA filters 0.3μm
• Class I BSC
  • Protect only the worker and environment (not items within BSC)
  • Draw in room air through front opening
• Class II BSC (Risk group 1-3)
  • Protects worker, environment, and items within BSC
  • Draws air through front sash into grill and filter
• Class III BSC (Risk group 1-4)
  • Protects worker, environment, and items within BSC
  • Inside of BSC is completed enclosed
    • Use attached gloves to handle items
  • Air is filtered twice