micropara

• Techniques for controlling pathogenic microorganisms

  • Killing microorganisms
  • Inhibiting the growth of microorganisms
• Cidal agents


  Agents which kill cells
• Static agents


  Agents which inhibit the growth of cells (without killing them)
• Physical control of pathogenic microorganisms

  • Heat
  • Filtration
  • Radiation
  • Ultrasonic vibration
• Heat - Sterilization


  1. Direct flame (incineration)

  2. Hot air oven

  3. Boiling water

  4. Autoclaving

  5. Fractional sterilization

  6. Pasteurization

  7. Flash pasteurization

  8. Ultra-pasteurization

  9. Hot oil
• Filtration


  • Inorganic filters (e.g. Seitz filter, porcelain, ground glass)
  • Organic filters (e.g. Berkefed filter using diatomaceous earth)
  • Membrane filters (e.g. cellulose acetate, polycarbonate)
• Radiation


  • Ultraviolet irradiation (damages bacterial DNA)
  • Ionizing radiation (x-rays, gamma rays eject electrons from organic molecules)
• Ultrasonic vibration


  High frequency sound waves propagated in fluids to cause microscopic bubbles that disintegrate microorganisms
• Preservation methods


  • Drying
  • Salting
  • Low temperature and freezing
• Chemical control of pathogenic microorganisms

  • Disinfectants
  • Antiseptics
• Phenol coefficient


  Indicates the ability of a chemical agent compared to phenol under similar conditions
• Phenol and phenolic compounds

  • Standard disinfectants, especially useful against Gram+ bacteria, coagulate bacterial proteins and cell membrane enzymes
• Halogens


  • Chlorine (used in water treatment)
  • Iodine (used as antiseptic for wounds)
• Heavy metals


  • Mercury (in products like mercurochrome, Merthiolate, metaphen)
  • Copper (used to control algae)
  • Silver nitrate (antiseptic and disinfectant)
• Alcohol


  Effective antiseptic applied on skin, acts as a strong dehydrating agent on vegetative bacterial cells
• Alkylating agents


  • Formaldehyde (inactivates viruses, produces toxoids)
  • Ethylene oxide (sterilizes plastic materials)
• Hydrogen peroxide


  Used for rinsing wounds, scrapes, and abrasions
• Soaps and detergents


  • Soaps have pH 8.0 that destroys some bacteria, mechanically washes skin surface
  • Detergents are strong wetting agents and surface tension reducers
• Dyes


  • Triphenylmethane dyes (antiseptic against Bacillus, Staphylococcus, Salmonella)
  • Acridine dyes (antiseptic against gonorrhea, staphylococcal infections), act by inhibiting bacterial DNA and RNA synthesis
• Aseptic technique


  • With traumatic wounds
  • In administration of injections/infusions
  • In surgery
• Aseptic technique


  • Keeping hands clean
  • Ensuring sterile items remain free from contamination
  • Avoiding breathing, coughing, sneezing on wounds or sterile items
• Medical asepsis


  Procedures to protect patient and environment from spread of infectious organisms, maintaining cleanliness to limit microbes to specific areas and render objects clean or dirty
• Principles of medical asepsis

  • Wash hands frequently
  • Keep soiled items from touching clean items/clothing
  • Don't place soiled items on floor
  • Avoid clients coughing/sneezing on others
  • Move equipment away when brushing/dusting
  • Avoid raising dust
  • Clean least soiled areas first
  • Dispose of soiled items directly into drain
• Medical asepsis


  Maintaining cleanliness to prevent the spread of pathogenic microorganisms and ensure the environment is free from microbes as much as possible
• Microbiology equipment


  A set of modern and often high-tech equipment used to facilitate the rapid culture, isolation and identification of microorganisms in specimen samples
• Medical asepsis


  • Limiting microbes to specific areas and rendering objects either clean or dirty
• Microscope


  • Used in the laboratory setting
• Test tubes and holders

  • Finger-like lengths of glass or clear plastic tubing which is open in one end and rounded with U-shaped bottom
• Microscope glass slides


  • Thin flat pieces of glass used to hold objects for examination under the microscope
• Inoculation loop


  • A simple tool used to retrieve an inoculum from a culture of microorganisms, also known as a smear loop, an inoculating wand or microstreaker
  • It is used in the cultivation of microbes on Petri dishes by transferring the inoculum for streaking
  • It is sterilized in a flame until it turns red-hot before and after each use to prevent cross-contamination
• Principles of Medical Asepsis

  • Wash hands frequently
  • Keep soiled items and equipment from touching skin and clothing
  • Do not place soiled bed linen or any other items onto the floor
  • Avoid having clients cough, sneeze, or breath directly on others
  • Move equipment away from you when brushing, dusting, or scrubbing articles
  • Avoid raising dust
  • Clean the least soiled areas first then move to more soiled ones
  • Dispose of soiled or used items directly into the drain
  • Avoid leaning against sinks, supplies, or equipment
  • Avoid touching your eyes, face, nose, mouth
  • Use particles of personal grooming that help prevent spreading microorganism
  • Follow guidelines conscientiously for isolation or barrier techniques as prescribed by agency
• Pipette


  • An instrument used to transport a measured volume of liquid, comes in different types such as fillers, helpers, light-guided pipetting systems, and pipette tips
• Bunsen burner


  • A laboratory equipment that produces a single open gas flame for heating, sterilization and combustion
• Basic Procedures of Medical Asepsis

  • Perform patient care handwash
  • Disinfect materials as required
  • Maintain a clean patient care environment
  • Use clean and dirty utility rooms
  • Store and handle linen properly
• Petri dish


  • A shallow cylindrical covered container or dish, often made of glass or plastic, used to culture cells or small moss plants
• Sterile Technique


  The way sterile materials are handled in order to keep them free of living microorganisms (germs)
• Medical autoclave

  • A device that uses steam to sterilize equipment and other objects in order to inactivate microorganisms
• Culture medium

  A liquid or gel designed to support the growth of microorganisms or cells
• Types of culture media

  • Nutrient broths
  • Agar plates
• Principles of Surgical Asepsis

  • Only sterile objects can touch another sterile object
  • Open sterile packages so that the first edge of the wrapper is directed away from the worker
  • Avoid spilling any solution on a cloth or paper used as a field for a sterile setup
  • Hold sterile objects above the level of the waist
  • Avoid talking, coughing, sneezing, or reaching over a sterile field or object
  • Never walk away from or turn your back on a sterile field
  • All items brought into contact with broken skin or used to penetrate the skin should be sterile
  • Use dry sterile forceps when necessary
  • Consider the edge (outer 1 inch) of a sterile field to be contaminated
  • Consider an object contaminated if you have any doubt as to its sterility