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effects of temperature on effectivness
increase temperature increases efficiancy
increases energy and they "bash" into each other
denatures
effects of increased volume
increased volume increases killing effect
effects of exposure rate
prolonged application can kill more
Cleanliness principle
clean surface first
rid of organic matter
disinfectants work better
Ideal disinfectant
no such thing
bad for us as well - we don't want to kill everything
too expensive
soaps and detergents
polar at one end non polar at the other end -like aphospholps
emulsfied ... cleanliness effect
disrupts membranes and impars proteins
Organic acids and bases
change pH (enzymes can't function)
Heavy metals:
Ag, Cu, Hg, Se
interact with amino, sulfy hydryls groups n proteins (substute groups in nucleic acids)
Halogens:
Iodine
binds to proteins
iodophors -organic molecule attached to iodine
acts like a detergent
halogens:
chlorine
chlorine bleach
strong oxidizer
effective but inactivated by organic matter
destroys bonds between monomers
Alcohols
denatures proteins; disrupts cell membranes
-best mixed with water
-disinfect, not sterilize (drys to fast)
alcohols:
phenols
denature proteins
action not impaired by presense of organic materials
Hydrogen peroxide
oxidizing agent
form free radicals
Alkylating agents
add functional groups to macromolectules
formaldehyde
inactive viruses, toxins
ethylene oxide
gas sterilization
Dry heat:
slowly oxidizes molecule
-requires higher temperatures
-takes long
Moist heat
denature proteins - breaks hydrogen bonds
quicker - water distributes heat better
-molecules banging around more
pasturization
slows microbial growth on food - to extend shelf life
bacteria still exists but as long as we don't overload out system can control them
Radiation:
UV light
low energy
not oxidizing
breaks hydrogen bonds
---have to overwhelm them to make them base pair with themselves
ionizing radiation
high energy
oxidizing
needs an electron so it goes takes one from another and then they need an electron and it's a chain reaction
radiation:
microwaves
lower energy
more efficeintly passed through water molecules
won't kill endospores -water isn't part of their system
Filtration
required pores smaller than pathogen
Thermal death point
temperature that kills all bacteria in 24 hours
thermal death time
time to kill all bacteria in a culture at a specific temperature
Phenol coefficient
compare all disinfectants performance with phenol when conditions are identical
estimate killing powe and come up with a ratio
1=phenol
<1=better than phenol
>1=less than phenol
Filter paper method of evaluating disinfectants
disks get saturated with disinfectant and placed on a medium that was innoculated ad let the bacteria grow
Use dilution for evaluationg disinfectants
make seial dilutions of disinfectant
take a bead that was contaminated with bacteria
place 1 bead in each dilution for a certain amount of time
take them out and inset in a broth
and see if anything grows
Inhibition of cell synthesis
inhibits formation of new peptidoglycon layer
-can't grow and can't repair damage with long term use
resistance is common
disrupt membrane function
resistance in some classes
inhibition of protein synthesis
targeting or taking advantage of the fact that prokaryote and eukaryotes are different enough to effect one instead of the other
attacks small ribosomes by altering target site
inhibiting of nucleic acid synthesis
atacks enxymes involed
attacks ones unique to the bacteria
fast acting because RNA is constantly being made
broad spectrum
: we have different enzymes than the bacteria but all bacteria have the same enzyme
competitive inhibition enzymes
competes for the active site on an enzyme
so the substrate can't
have to have a higher amount it than the substrate
Broad spectrum
prokaryotic specific
works on a wide range of groups
cons
: we have good microbes within us they could kill
selective for resistance
: killing for one genes while other may not have that gene
narrow spectrum
works on a narrow range
specific bacterium
used most often when
: don't know what the bacterium is and the patient is dying
Chemotherapy index
ratio of toxis dosage level vs. therapeutic dosage level
max tolerance dose
min dose that cures dz
1=close to killing yourself
100=a lot safer
>1=suicide
mutualism
both benefit
commensalism
host benefits
no positive or negative effect on virus
parasitism
virus benefits
host is harmed
resident
found in one spot
we expect to find it there
transient
don't expect to find it there
opportunist
take advantage of a situation
immunocompromised
introduced into unusual body site
disturbed microbiota
opportunist:
imnocomromised
body already is fighting a dz
stress - depresses immune system
chemothereapy
opportunist:
disturbed microbiota
where you expect to find them
keeping each colony in check
1 or 2 or more colonies removed leave a chance open for other colonies to be introduced or already existing colonies take over
how microbes cause dz
infect
: -gain acces - adhere to cell surface - or invade tissues - multiply
produce toxins
use energy and monomers from host -decreasing host growth and repair
Sterilize
to free from living microorganisms by the use of physical or chemical agents, depriving thm of the ability to reproduce
disinfect
the act of freeing something from infections by destroying harmful microorganism
antiseptic
free of living microorganisms
sanitizer
a substance of preparation for killing germs
bacteriostatic
inhibition of the growth of bacteria withou destruction
bactericidal
destroying bacteria
germicidal
any substance that kills germs or other microorganisms
viricidal
an agent that inhibits or destroys viruses
fungistatic
capable of inhibiting the growth and reproduction fo fngi without destroying them
fungicidal
destroying fungi
sprocidal
tending to kill spores
Author
tigray
ID
68796
Card Set
Medical Microbiology
Description
exam 2 need to knows
Updated
2011-02-25T03:14:59Z
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