question

sterilization

answer

removal or destruction of ALL microbes

question

disinfection

answer

treatment of inanimate objects; cannot inhibit endospores or some viruses

question

antisepsis

answer

when a chemical is used on skin or other tissues

question

pasteurization

answer

the use of heat to kill pathogens/spoilage microbes in food and beverages

question

microbistatic treatment

answer

stop binary fission but DOES NOT KILL cells

done with LOW TEMPERATURES

question

microbicidal treatment

answer

KILLS CELLS

done at HIGH TEMPERATURES

question

microbial death

answer

the permanent loss of reproductivity ability under ideal environmental conditions (HAS PERMANENTLY LOST ABILITY TO UNDERGO BINARY FISSION)

question

modes of action

answer

processes that are damaging the cell leading to death

1. alteration of cell wall and cell membrane
2. damage to proteins and nucleic acids

*we target these things because they are essential structures and processes that will cause cell to die if damaged

question

what does alteration of a cell wall or cell membrane do?

answer

-damage to cell wall makes the cell more susceptible to hypotonic environments
- damage to the cell membrane would allow cellular contents to leak out
- damage to a viral envelope would prevent viral replication

question

what does damaging proteins and nucleic acids do?

answer

- denatured proteins cease to function, bringing about cellular death
- damage to nucleic acid molecules could produce fatal mutations and stop protein synthesis

question

what factors affect how effective treatment is?

answer

1. THE SITE TO BE TREATED: is it animate or inanimate? will it have to penetrate tissue/ mucous membrane or only contact the surface
2. THE RELATIVE SUSCEPTIBILITY OF MICROBES THAT ARE PRESENT:
(most resistant>) prions, bacterial endospores, mycobacteria, cysts of protozoa, active-stage protozoa, most gram negative bacteria, fungi, non enveloped viruses, most gram positive bacteria, enveloped viruses (
3. ENVIRONMENTAL CONDITIONS: temperature and pH affect effectiveness of treatments. Is organic material present? this also effects effectiveness.

question

physical methods vs chemical methods of treatment

answer

PHYSICAL:
- heat related: all achieve sterilization, moist heat (boiling, autoclaving, pasteurization) OR dry heat (over, complete incineration)
- refrigeration and freezing: don't kill so they do not achieve sterilization
- desiccation: dehydration at room temperature, doesn't achieve sterilization
- filtration: achieves sterilization (good for liquids that are heat sensitive)
- osmotic pressure: controls growth but not sterilization because endospores are not susceptible
- radiation: achieves sterilization

CHEMICAL METHODS
- phenolics, alcohols, ozidizing agents, heavy metals, surfactants.
- used primarily as disinfectants and antiseptics, endospores are typically resistant.

question

what is desiccation

answer

dehydration at room temp
* DOESNT ACHIEVE STERILIZATION

question

why does osmotic pressure not achieve sterilization?

answer

osmotic pressure controls growth but because endospores are not susceptible to be harmed by this it doesn't achieve COMPLETE sterilization, it is used for FOOD PRESERVATION

question

which PHYSICAL methods of treatment achieve sterilization??

answer

- (gamma rays) (uv can achieve but not reliably)
- dry oven or autoclave
- filtration

(osmotic pressure, boiling, mild heat, pasteurization, uv radiation, desiccation, refrigeration, and freezing do not achieve sterilization)

question

do CHEMICAL methods of treatment sterilize?

answer

NO, primarily used as disinfectants and antiseptics because endospores are resistant.

question

disinfection vs antiseptic?

answer

antiseptic on skin
disinfection on inanimate objects

question

modes of action vs mechanisms of action

answer

modes of action= chemical or physical
mechanisms= specific cellular targets

question

what are the mechanisms of action or cellular targets of controlling growth? (antibiotics)

answer

1. inhibition of cell wall synthesis
2. inhibition of protein synthesis (very complex so useful for targeting specific part)
3.disruption of cytoplasmic membrane
4. inhibition of DNA or RNA synthesis (only synthesis disrupted)
5. inhibition of general metabolic pathway such as folic acid (inhibiting folic acid synthesis which is needed to make DNA and RNA in prokaryotes, but not in eukaryotes. prokaryotes dies from not making folic acid)
6. inhibition of pathogens attachment or entry into host celll ( mostly for viruses)

question

what does inhibition of folic acid do?

answer

prevents PROKARYOTIC cells from making DNA and RNA

(doesn't affect eukaryotic so its good for antibiotic use)

question

selective toxicity

answer

antibiotics are selectively toxic so they they interrupt SOMETHING SPECIFIC to the bacteria/ prokaryotic cell

question

we want to ____________ selective toxicity in order to kill only the ______________ cell and not the ___________ cell

answer

we want to use INCREASE selective toxicity in order to kill only the PROKARYOTE and not the EUKARYOTE

question

the more selectively toxic an antibiotic is the less toxic it is for _____________

answer

US!!!

question

what are the 5 cellular targets in order of ranking? (not including inhibition of attachment which is mostly for viruses)

answer

1. inhibition of cell wall synthesis (selective) (we don't have a cell wall)
2. inhibition of folic acid synthesis (selective) (we don't make folic acid)
3. inhibition of protein synthesis (ribosomes differ, could be selectively toxic)
4. inhibition of nucleic acid synthesis (toxic)
5. disruption of cell membrane (toxic)

question

side effects of antibiotics

answer

- toxicity
-allergies
- disruption of normal microbiota
- secondary infections/super infection - result because you took an antibiotic
- antibiotic kills all bacteria it can. whatever it leaves behind may be able to grow more in number and cause a second infection such as a yeast infection) (yeast is fungal and cannot be killed by antibiotic so yeast flourishes when other bacteria are killed)

question

how would an individual, existing cell gain the ability to resist the effect of an antibiotic?

answer

because antibiotic use selects for resistant bacteria (it kills off the ones that are not resistant leaving ones that are and causing the population to shift to more resistant) *WE don't become resistant, its the bacteria that is becoming resistant

question

to begin a populations phenotype may be__________but then overtime by use of antibiotics the phenotype changes to_________________

answer

drug sensitive> drug resistant

*demonstrates evolution and survival of the fittest

question

where do resistant cells come from?

answer

1. binary fission- if parent cell has gene for antibiotic resistance it will pass on to offspring
2. if a parent cell is not resistance and daughter cell shoes evidence of antibiotic resistance this is due to a MUTATION
3. a cell born sensitive how can it gain the ability to have resistance? HORIZONTAL GENE TRANSFER

question

how would an individual, existing cell gain the ability to resist the effects of an antibiotic?

answer

an existing cell can gain material through horizontal gene transfer (conjugation, transformation, or transduction)

question

what are the three types of horizontal gene transfer?

answer

1. conjugation
2. transformation
3. transduction

question

MECHANISMS OF RESISTANCE

answer

1. enzymatic destruction
2. slow/prevent entry
3. alter target
4. efflux pumps- cell has to make this pump (transport protein) and put it into its membrane (requires new genetic material) (pumps out antibiotic as soon as it enters, they are not antibiotic specific so bacterial cells that make these pumps are resistant to most antibiotics)
5. biofilms- cells in biofilm have resistance to an antibiotic because they make the extracellular matrix which is very hard to penetrate so antibiotics can't get to cells giving them protection

question

if an antibiotic is resistant to methacyclin this means what

answer

it is very resistant, probably to many other things as well

question

enzymatic destruction of antibiotic

answer

bacterial cell makes enzymes which destroy the antibiotics (enzymes are selective)

question

slowing and preventing entry of antibiotic

answer

cell can't make receptor so antibiotic can't get in

question

altering the target of the antibiotic

answer

the antibiotics target on the cell is altered so that it can no longer bind to where it wants to.

question

what are our options of treatment when these bacterial cells are so resistant?

answer

1. sufficiently high concentration of drug maintained for a long enough time to inhibit the pathogen
2. use of antibiotics in combination
3. limit use of antibiotics to necessary cases
(50% of sore throats and 30% of ear infections are viral, not bacterial)
4. develop new drugs *there is a new gram positive bacteria targeting antibiotic that can cill methicillin resistant staphylococcus aureus

question

bacteriophage boom

answer

classically the treatment uses a bacteriophage, or cocktail of severe, to specifically target the lyse of target pathogenic bacteria

question

what is an example of when bacteriophage are being used for treatment?

answer

MEATS!! used to treat and make meats safer

question

probiotics
vs
antibiotics

answer

probiotic- "for life" "keeps alive". something we ingest that contains beneficial living microbes that enhance and increase number of beneficial microbes in GI tract

antibiotic- "against life" "kills"

question

what do cold temperatures do?

answer

1. inhibit metabolism
2. food preservation

question

what does a dry oven do

answer

1. denatures proteins, destroys membrane
STERILIZATION

question

what does boiling do

answer

1. denatures proteins, destroys membranes

DISINFECTION

question

what does mild heat, killing pathogens, and spoilage microbes do?

answer

denatures proteins, destorys membranes
*PASTEURIZATION

question

what does an autoclave do?

answer

denatures proteins, destroys membranes
STERILIZATION

question

what do gamma rays do?

answer

damages DNA
STERILIZATION

question

what do UV radiation do?

answer

damage DNA
DISINFECTION
*CAN ACHIEVE STERILIZATION BUT NOT RELIABLY

question

out of gamma rays and UV radiation which one disinfects and which one sterilizes?

answer

gamma rays sterilize
uv radiation disinfects

question

osmotic pressure does what

answer

inhibits metabolism
*FOOD PRESERVATION

question

alcohol does what

answer

disrupts cell membranes
DISINFECTION OR ANTISEPSIS

question

phenol/phenolics do what

answer

denature proteins, disrupt cell membranes
DISINFECTION AND ANTISEPSIS

question

filtration does what

answer

separates microbes from air and liquids
STERILIZATION

question

are enveloped or non enveloped viruses harder to kill?

answer

non enveloped are harder to kill because the envelope makes for an easy target

question

log phase vs stationary phase cells

answer

log phase are more susceptible because they are synthesizing and this is disrupted

Bacteria most susceptible in log phase due to production of new cells
Antibiotics inhibit cell wall formation
Antibiotics inhibit DNA replication
Antibiotics inhibit protein synthesis

question

some examples of environmental conditions that affect treatment are

answer

- porous of smooth surface
- organic materials present- animate of inanimate?

question

standard petri dishes are made out of heat-sensitive plastic, but ned to be sterilized before use. how can we do this?

once the plate has been used for bacterial culture, it once again must be sterilized. considering it is only used once (disposable) how might this be achieved?

answer

radiation

autoclave

question

any treatment of skin is referred to as

answer

antisepsis (soap, alcohol)

question

how is antisepsis achieved

answer

soap and alcohol

question

a needle that is heat stable needs to be made safe

answer

autoclave (high pressure steam)
sterilization

question

the antibiotic which is heat sensitive, needs to be prepared for injection what method should you use?

answer

filtration, which achieves sterilization because its going in the body

question

alcohol is used to wipe of a stethoscope, what outcome is this?

answer

disinfection (because its not penetrating this is sufficient)

question

chemotherapeutic agents are?

answer

what are used to control microbial growth inside human host
1. antibiotics, antivirals, antifungals

question

in most cases what essential cellular structure is interrupted to control growth
because of this are log phase more or less susceptible?

answer

SYNTHESIS
log phase are more susceptible because they are synthesizing new cells!

question

degerming

answer

Degerming is the removal of microbes from a surface by
scrubbing, such as when you wash your hands or a nurse prepares an area of skin for an injection. Though chemicals such
as soap or alcohol are commonly used during degerming, the
action of thoroughly scrubbing the surface may be more important than the chemical in removing microbes.

question

sanitation

answer

is the process of disinfecting places and
utensils used by the public to reduce the number of pathogenic microbes to meet accepted public health standards. For
example, steam, high-pressure hot water, and scrubbing are
used to sanitize restaurant utensils and dishes, and chemicals are used to sanitize public toilets.

question

sanitation vs disinfection

answer

sanitation- PUBLIC
disinfection- HOME/ NOT PUBLIC

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