Aseptic Technique & Culturing Microbes
Aseptic Technique & Culturing Microbes
Questions
A. What is the difference between a bactericidal and bacteriostatic agent? What is the difference between sterilization and disinfection?
Control of growth refers to the prevention of growth of microorganisms. This control is affected in two basic ways: by killing microorganisms or by inhibiting the growth of microorganisms. Control of growth usually involves the use of physical or chemical agents which either kill or prevent the growth of microorganisms. Agents that kill cells are called cidal agents; agents that inhibit the growth of cells without killing them are called static agents. Thus the term bactericidal refers to killing bacteria, and bacteriostatic refers to inhibiting the growth of bacterial cells.
Sterilization is the complete destruction or elimination of all viable organisms in or on an object.
There are no degrees of sterilization; an object is either sterile or it is not. Sterilization Procedures involve the physical removal of cells or the use of heat, radiation, or chemicals.
Disinfection simply means that you are reducing the microbial load on an object. Since this is usually done to render the object less likely to be involved in the transmission of infection, a good disinfection procedure is aimed at specifically reducing the numbers of potentially pathogenic organisms in the context of the use of the object being disinfected.
B. List five microbial killing methods, how they work, and what they are used for.
1.Filtration – involves the physical exclusion and removal of all cells in a liquid or gas, and is especially important to sterilize solutions which would be denatured by heat (antibiotics, injectable drugs, vitamins, etc.).
2. Boiling – at 100oC for 30 minutes kills almost all endospores. Very long or intermittent boiling is required to
Questions
A. What is the difference between a bactericidal and bacteriostatic agent? What is the difference between sterilization and disinfection?
Control of growth refers to the prevention of growth of microorganisms. This control is affected in two basic ways: by killing microorganisms or by inhibiting the growth of microorganisms. Control of growth usually involves the use of physical or chemical agents which either kill or prevent the growth of microorganisms. Agents that kill cells are called cidal agents; agents that inhibit the growth of cells without killing them are called static agents. Thus the term bactericidal refers to killing bacteria, and bacteriostatic refers to inhibiting the growth of bacterial cells.
Sterilization is the complete destruction or elimination of all viable organisms in or on an object.
There are no degrees of sterilization; an object is either sterile or it is not. Sterilization Procedures involve the physical removal of cells or the use of heat, radiation, or chemicals.
Disinfection simply means that you are reducing the microbial load on an object. Since this is usually done to render the object less likely to be involved in the transmission of infection, a good disinfection procedure is aimed at specifically reducing the numbers of potentially pathogenic organisms in the context of the use of the object being disinfected.
B. List five microbial killing methods, how they work, and what they are used for.
1.Filtration – involves the physical exclusion and removal of all cells in a liquid or gas, and is especially important to sterilize solutions which would be denatured by heat (antibiotics, injectable drugs, vitamins, etc.).
2. Boiling – at 100oC for 30 minutes kills almost all endospores. Very long or intermittent boiling is required to