Lecture 11 - Microbial Control Flashcards
Four possible outcomes microbial control outside the body
sterilization
disinfection
antisepsis
decontamination
what is the primary targets of microbial control?
microorganisms capable of causing infection or spolage
Considered the most resistant microbial entities
bacterial endospores
Destruction of endospores is the goal of ____.
sterilization
most resistant type of microbial forms
- prions
least resistant type of microbial forms
- enveloped viruses
A process that destroys or removes all viable microorganisms, including viruses.
sterilization
any material that has been subject to sterilization
sterile
sterilized products are essential to human well being (3)
- surgical instruments
- syringes
- commercially packaged foods
The use of a physical process or a chemical agent to destroy vegetative pathogens but not bacterial endospores.
disinfectection
are normally only used on inanimate objects
disinfectants
the growth of microorganisms in blood and other tissues
sepsis
any practice that prevents the entry of infectious agents into sterile tissues and prevents infection
asepsis; aseptic techniques
chemical agents that kill microorganisms
germicide and microbicide
chemical that destroys bacteria except for those in endospore stage
bactericide
kills fungal spores, hyphae, and yeasts
fungicide
inactivates viruses, especially on living tissue
virucide
capable of killing endospores
sporicide
Prevent the growth of bacteria on tissues or objects in
the environment
bacteriostatic agents
Inhibit fungal growth
fungistatic chemicals
Chemicals used to control microorganisms in the body (antiseptics and drugs)
microbistatic agents
Any cleansing technique that mechanically removes
microbes and debris
• Reduces contamination to safe levels
sanitization
- reduction of the # of microbes on the skin
- involves scrubbing the skin or immersing it in chemicals or both
- emulsifies oils on the outer cutaneous layer
- mechanically removes potential pathogens on the outer layers of the skin
antisepsis/degermation
expected to come into contact with sterile tissues
critical medical devices
comeinto contact w/t mucosal membranes
semi critical medical devices
those that not touch the patient or are only expected to touch intact skin
non critical medical devices
factors that affect death rate (7)
- # of microorganisms
- nature of the microbes the population
- type of microbial growth
- tempt and pH of environment
- concentration of the agent
- mode of action of the agent
- presence of solvents, interfering organic matter, and inhibitors
• Cellular targets of physical and chemical agents:
- cell wall
- cell membrane
- DNA RNA
- proteins
how protein can be altered (3)
- complete denaturation
- different shape
- blocked active site
are inserted into the lipid bilayer to disrupt it and create abnormal channels that alter permeability and cause leakage both into and out the cell
surfactant molecules
the most widely used method of microbial controls
heat
other methods of microbial control
radiation
filtration
ultrasonic waves
cold
Hot water, boiling water, steam
Temperature ranges from 60°C - 135°C
moist heat
air with a low moisture content that has been heated by a flame or electric heating coil
160c - 1000c
dry heat
exhibit the greatest resistance to disinfection methods
bacterial endospores
destruction of spores usually requires
temperatures above boiling
vary in their sensitivity to heat
vegetative cells
the shortest length of time required to kill all test microbes at a specified temperature
thermal death time