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• Biosafety cabinet


  Used as the primary means of containment for working safely with infectious microorganisms
• Class II Biosafety Cabinet


  • Provides protection to the user, the experimental material and the environment
  • The type most commonly used in biomedical and microbiological laboratories
• Air flow in Class II Biosafety Cabinet

  1. Drawn from the room around the operator into the front grille of the cabinet, providing personnel protection

  2. Downward laminar flow of HEPA-filtered air provides protection for experimental material inside the cabinet

  3. Cabinet air has passed through the exhaust HEPA filter and may be recirculated back into the laboratory (Class II Type A) or ducted out of the building (Class II Type B)

  
• Class III Biosafety Cabinet


  • Most suitable for work with biohazardous agents requiring high containment (biosafety level 3 or 4)
  • Completely enclosed, HEPA filter-ventilated cabinet fitted with glove ports and decontamination capabilities for entry and exit of material
  • Offers the highest degree of personnel and environmental protection from infectious aerosols
• Incubator

  • A device used to grow and maintain microbiological cultures or cell cultures
  • Maintains optimal temperature, humidity and other conditions such as the CO2 and oxygen content of the atmosphere inside
  • Essential for much experimental work in cell biology, microbiology and molecular biology
  • Used to culture both bacterial and eukaryotic cells
• Sterilization


  Complete destruction of ALL microbes
• Disinfection


  Killing of pathogens on inanimate objects, physical or chemical
• Antiseptic


  A chemical agent for disinfection of living tissue, external skin, mouth vagina
• Bacteriocide


  Kill microbes, also germicide, fungicide, virucide
• Bacteriostatic


  Prevents or stops microbial growth, also fungistatic, virustatic
• Aseptic (Asepsis)


  Prevent contamination of person or object by microbes
• Sanitize


  Removal of pathogens from inanimate objects, mechanical or chemical cleaning
• Contamination


  Presence of living microbes on object
• General rule for disinfection


  1. Clean then disinfect

  2. Use at recommended strength

  3. Prevent contamination of disinfectant

  4. Prepare fresh
• Phenols


  • Rupture the cell membrane
  • Denature enzymes (protein)
  • Effective in presence of organic matter
• Halogens


  • Effective against Hepatitis, HIV
  • Chloride: Bacteriocide, fungicidal, virucidal
  • Iodine: Skin antiseptic, environmental disinfectant
• Metal ions


  • Silver: 1% AgNO3 eye drops for gonorrheal neonatal ophthalmitis
  • Mercury: HgCl2 skin antiseptic, Mercurochrome
  • Copper, zinc: Fungicide, algacide
• Alcohols


  • Detergents: Surface active
  • Alkylating agents: Cross link proteins, nucleic acids
  • Ethylene Oxide: Sterilizes heat sensitive or chemical sensitive objects
• Hydrogen peroxide


  • Disinfectant - 6%
  • Bactericidal
  • Fungicidal
  • Virucidal
• Ozone


  • Used in industrial settings to sterilize water and air, as well as a disinfectant for surfaces
• Vaporized hydrogen peroxide


  • Steam formaldehyde
• Physical sterilization methods


  • Moist heat
  • Dry heat
  • Irradiation
  • Sterile filtration
• Moist heat sterilization


  The most widely used and reliable sterilization method
• Dry heat sterilization


  Appropriate for materials that cannot withstand moist-heat sterilization
• Autoclaving


  Sterilizes equipment and supplies by subjecting them to high pressure saturated steam at 121°C or more, typically for 15 minutes under pressure 15 bp
• Dry heat sterilization


  1. Transfers heat energy from air inside the oven to the instruments

  2. Requires higher temperatures

  3. Good for items that are likely to dull or rust in the autoclave, powders, cellulose and ink

  4. Packaging must be able to withstand high temperatures
• Dry heat sterilization methods

  • Hot oven: 160°C for 2 hours or 180°C for 30 min
  • Flaming: for loops and straight-wires in microbiology labs
  • Incineration: Burn any organism to ash
  • Boiling: for 15 minutes, ineffective against prions and many bacterial spores
• Rapid dry heat sterilization


  Heats air to 190°C (374°F) for 6 minutes for unwrapped objects and 12 minutes for wrapped objects
• Chemical (gas) sterilization


  Used to sterilize surfaces and porous materials that other sterilization methods may damage, using ethylene oxide generally in combination with heat and moisture
• Radioactive sterilization


  Suitable for the industrial sterilization of contents in sealed packages that cannot be exposed to heat, using electromagnetic or particulate radiation like gamma-rays and ultraviolet (UV) light
• Ultraviolet (UV) light


  • Less damaging and less lethal to microorganisms, but poor penetration and less efficient
• Gamma-rays (ionising radiations)


  • Cause both excitation and ionization of atoms of different molecules in microorganisms
• Mechanical sterilization (filtration)


  1. Removes but does not destroy microorganisms, clarifies solutions by eliminating particulate matter

  2. Depth filters trap particles in channels

  3. Screen (membrane) filters are films made of various materials
• Liquid chemical sterilant/disinfectants are only for heat-sensitive critical and semi-critical devices, but raise safety concerns due to being powerful and toxic</b>
• Heat tolerant or disposable alternatives are available for liquid chemical sterilant/disinfectants