Control Methodologies for Sterilization and Disinfection Flashcards
What is sterilization
Total destruction of all microbes, including bacterial spores, mycobacteria, naked capsid, viruses, and fungi
How is sterilization achieved?
Achieved by dry or wet head, certain gases, and certain chemicals
What is autoclaving
use of moist high heat for at least 15 minutes
Rate of killing organisms is affected by
size of autoclave
temperature and time
steam flow rate
location of material in the chamber
density and size of load
How do you do a routine check of autoclave
spore test
error in sterilization process= spores germinate and grow
What is dry heat treatment
exposure to 160 degrees for 2 hours or 1 hour
ultraviolent radiation sterilizes by damaging DNA
Ionizing radiation sterilizes by knocking off electrons from biomolecues
What factors affect antimicrobiral activity
population size (load)
population composition
True/false: Larger microbial populations take faster to kill than smaller populations
FALSE: larger population take longer to kill than smaller populations
True/false: microorganisms differ markedly in their sensitivity to antimicrobial agents
true
What is a vegetative cell
active form of bacterial cells
metabolically active but NOT undergoing cell division
What is a endospore
form form of a cell
Allows for survival of adverse conditions but does not allow the cell to grow or reproduce
Does germicide kill endospore
Germicide kills pathogens and many nonpathogens but not necessarily endospores
What is germicide effective against
bactercides, sporicide, fungicides, algicides, and viricides
bacteriostatic and fungistatic agents
inhibits growth
not as harmful to microbes as -cides
what does bacteriostatic solution do
prevent the growth of bacteria on tissues or on objects in the environment
What is disinfection
use of physical or chemical methods to destroy MOST microorganisms
levels of disinfection
High
Intermediate
Low
What is high-level disinfection
usually emulates efficiency of sterilization
What is intermediate-level disinfection
bacterial spores can survive
used to clean surfaces or instruments under conditions where contamination with bacterial spores is not likely
Low- level disinfection
kills most vegetative bacteria and lipid-enveloped viruses
What is low-level disinfection used for
disinfect noncritical instruments including stethoscopes
Mechanisms of harm of disinfections
protein denaturation
membrane disruption
nucleic acid damage
inhibition of metabolism
DNA interference
What are phenols and phenolics
denature proteins and disrupt lipidic membranes
not effective against spores at room temp and has poor activity against naked capsid viruses
What are phenolic compounds active against
myobacteria
Chlorhexidine
used as a hand and skin antiseptic
broad spectrum of action: binds to tissues and has persistent antibacterial activity
what does chlorhexidine reduce
gingival inflammation, plaque, and bleeding
What does chlorhexidine inhibit
sugar transport in streptococci
amino acid uptake and catabolism in S. sanguinis
P. gingivalis protease
Membrane functions, including ATP synthase and maintenance of ion gradients in streptococci
binding of plaque-forming bacteria
