Microbiology: Chapter 7 Flashcards
What method of microbial control completely destroys all forms of microbial life?
What is commercial sterilization?
Limited heat treatment, destroys pathogens but not all bacteria (killing C. botulinum endospores)
What method destroys the vegetative cells on a surface?
What is a disinfectant?
Chemical treatment used to disinfect inanimate objects (removal of pathogens)
What method is treatment of living skin or tissue to kill microorganisms (removal of pathogens from living tissue)?
What is physical removal of microbes (alcohol swab, soap) - as in cleaning the skin prior to injections?
What is sepsis?
Refers to microbial contamination
What is asepsis?
The absence of significant contamination
What prevents microbial contamination of wounds?
Aseptic surgery techniques
What is the systematic cleansing of inanimate objects to reduce the microbial count to a safe level (for public health, used in restrooms, kitchens)?
What is bactericidal?
(-cidal, to kill); kill all bacteria
What is bacteriostatic?
(-static, to stop); halt (inhibit) the growth of bacteria for as long as the inhibitory substance is present; if inhibitor is removed, growth begins again
Microbial death (same as growth) occurs how?
Killing in a population is not instantaneous, it occurs exponentially
What does the effectiveness of antimicrobial treatment depend on?
Number of microbes
Environment (organic matter, temperature, biofilms)
Time of exposure (need time for disinfectant to work, then wipe)
Microbial characteristics (if unfavorable conditions then will make endospore)
What is thermal death time (TDT)?
The time at a given temperature in which all the microorganisms in a liquid culture will be killed.
What is thermal death point (TDP)?
The lowest temperature at which all microorganisms in a liquid suspension are killed in 10 minutes.
What is heat sterilization?
High heat and high humidity together are the most effective in killing microorganisms, but dry heat can also be used.
What is tyndallization?
Sterilization of a fluid by heating it repeatedly to a point slightly below that of boiling. With each heating the bacteria which have developed from the more resistant spores are destroyed; when finally no undeveloped spores remain the fluid is sterile.