Chapter 7 Flashcards
disinfection
reducing the number of pathogenic organisms on objects or in materials so that they pose no threat of disease
sanitization
to remove microbes or reduce their populations to a safe level as determined by public health standards
sterilization
killing of all microorganisms, including bacterial spores
antiseptics
chemical agents that can be used safely on skin and tissues to destroy microbes or inhibit their growth
alcohol
damages membrane and denatures proteins
not effective against spores
used in many hand sanitizers
phenols
denature proteins
causes damage to skin - not used
bisphenols
derivative of phenol - two phenols together
used instead of phenol
halogens
oxidize proteins
e.g. chlorine
iodine
modifies proteins
used as antiseptic on wounds and in surgery
iodophors
release iodine over a long period of time and don’t stain
e.g. Wescodyne
ethylene oxide gas
alkylation - throw alkyl groups onto protein to deactivate them
hydrogen peroxide
antiseptic rinse for wounds and scrapes
catalase in tissue breaks it down into oxygen, which acts against anaerobes
bubbling loosens dirt and dead tissue
dyes
modifies nucleic acid
e.g. crystal violent - skin antiseptic
formaldehyde and glutaraldehyde
alkylation - denatures proteins and nucleic acids
phenol coefficient
determines effectiveness of a chemical agent as a disinfectant compared to phenol (the gold standard)
higher than 1 - better than phenol
high level disinfectant
destroys all microbes, but not all spores
intermediate level disinfectant
destroys all vegetative bacteria including mycobacteria (TB bacterium), fungi, and most viruses
low level disinfectant
destroys fungi, vegetative bacteria except mycobacteria, and some viruses
autoclave
physical sterilization agent uses steam to kill temp: 121.5°C pressure: 15 lbs/in2 time: 15 mins
autoclave - flash cycle
temp: 134°C
pressure: 30 lbs/in2
time: 3 mins
Geobacillus stearothermophilus
gold standard used for autoclaves - toughest spores
disadvantages of autoclave
damage to plastic and rubber items
corrodes metal items
may leave water deposits, may be wet
dry heat oven
physical sterilization agent
temp: 160°C
time: 2 hours
advantages of dry heat oven
no corrosion
low cost
items are dry
disadvantages of dry heat oven
long
damage to plastic and rubber items
can’t sterilize liquids
pasteurization
physical agent - kills potential pathogens in milk, especially TB bacterium
heat milk - 62°C for 30 mins
flash pasteurization
72°C for 15 seconds
UV radiation
creates thymine dimers
X-ray radiation
produces free radicals - destroy DNA
filtration
for liquids
to get rid of pyrogens (LPS lipid A) as well as sterilize
