Spread and control of infection


Sterilization

  • complete killing, or removal, of all living organisms from a particular location or material.
  • Classical sterilization techniques using saturated steam under pressure.
  •  Other methods include filtration, ionizing radiation (gamma and electron-beam radiation), and gas (ethylene oxide, formaldehyde).

 

  Steam sterilization


  • Performed in Autoclave
  • Exposure of microorganisms to saturated steam under pressure
  • Cause destruction by the irreversible denaturation of enzymes and structural proteins
  • requires precise control of time, temperature, and pressure
  • The recommendations for sterilization in an autoclave are 15 minutes at 121-124 °C (200 kPa)

 

 

Dry-heat sterilization

  • Requires a higher temperature than moist heat and a longer exposure time.

  • It is more convenient for heat-stable, non-aqueous materials that cannot be sterilized by steam
  • E.g. glassware, powders, oils, and some oil-based injectable

 

 

Filtration

  • Mainly for thermolabile solutions
  • May be sterilized by passage through sterile bacteria-retaining filters
  • e.g. membrane filters (cellulose derivatives, etc.), plastic, porous ceramic, or suitable sintered glass filters, or combinations of these
  • Usually, membranes of not greater than 0.22 μm nominal pore size should be used

 

 

 

Exposure to ionizing radiation

  • Certain active ingredients, drug products, and medical devices sterilized by ionizing radiation in the form of gamma radiation
  • Laws and regulations for protection against radiation must be respected.

 

 

Pasteurization

  • The use of heat at a temperature sufficient to inactivate important pathogenic organisms in  water or milk
  • At a temperature below that needed to ensure sterilization
  • For example, heating milk at a temperature of 74°C for 3 to 5 seconds or 62°C for 30 minutes
  • It kills the vegetative forms of most pathogenic bacteria that may be present without altering its quality. 
  • Spores are not killed at these temperatures.

 

 

Disinfection

  • The reduction in the number of bacteria, viruses, or fungi to a desired concentration
  •  Some of the disinfectants like  alcohols, chlorine and chlorine compounds, formaldehyde, glutaraldehyde etc
  • Chlorination of water is disinfection

 

 

Antisepsis

  • The destruction or inhibition of microorganisms on living tissues, thereby limiting or preventing harmful results
  • For example the use of tincture, povidine  iodine on skin wound.

  • Hydrogen per oxide 

Sanitization
  • A process of cleaning certain area or surface in such a manner so that it is made bacteria-free and elementally clean all types of microbes and viruses that can infect the human body and cause different kinds of diseases
  • It may be hand sanitization or Surface sanitization