MODULE 8

Question 1

what are three ways we control microbes

Answer 1

• Kill
• Remove
• Prevent growth

Question 2

what is sterilization, disinfection and sanitation in terms of inanimate items

Answer 2

○ Sterilize - remove all vegatative cells, microbes, endospores etc
○ Disinfection - reduces and destroys the microbial load
○ Santitation - reduce microbes to safe public health level

Question 3

what is antisepsis/antiseptic and degerming in living tissues

Answer 3

○ Antisepsis/antiseptic - reduces microbial load
○ Degerming - Reduce load using scrubbing and mild chemicals

Question 4

Protocols are affected by (4)

Answer 4

1. Time of exposure
2. Temperature/Concentration
3. Microbial load
4. Type of microbe

Question 5

what are the resistance level of microbial types from susceptible to resistant

Answer 5

lipids + med size virus
vegetative bacteria
vegetative fungi
fungal spores
mycobacteria + small viruses
parasitic oocytes
bacterial spores
prions

Question 6

whats the one mechanical method of control

Answer 6

filters

Question 7

what are 2 methods of physical control

Answer 7

heat and radiation

Question 8

what does heat do in control

Answer 8

Denatures protein and DNA and melts lipids

Question 9

TF Dry heat is much better than moist heat

Answer 9

F, moist is better bc heat transfers thru water better

Question 10

TF pasteurization sterilizes microbes

Answer 10

F, just eliminates pathogens (makes safe)

Question 11

what are the physical methods of heating that lead to sterilization

Answer 11

• incineration/dry oven
• steam pressure autoclave
• X-ray (ionizing)

Question 12

what are the physical methods that lead to dininfection

Answer 12

• boiling water/pasteurization
• UV (non ionizing)

Question 13

Autoclaves _______ at _____°C for ____minutes or more

Answer 13

Sterilize
121
15

Question 14

UV light Only kills _______, no penetrating power, X-RAy causes _____ and will sterilize

Answer 14

surface
DNA damage

Question 15

filters _____ bacteria, not_______ them

Answer 15

remove
kill

Question 16

what does a red medium vs a yellow medium mean in autoclaving

Answer 16

red = autoclave worked (spores dead)
yellow = autoclave failed (spores alive)

Question 17

why are spores used in an autoclave

Answer 17

most resistant, if spores die, everything else is dead too

Question 18

what are the 2 chemical methods

Answer 18

liquid and gases

Question 19

whats the difference between germicides, chemotherapy and preservatives

Answer 19

germicides: chemical used to kill microbes on surfaces
chemotherapy: chemical used as therapeutic to kill or prevent growth of microbes
preservatives: chemical that kill microbes or inhibits microbial growth by creating an unfavorable environment

Question 20

TF selective toxicity only applies to chemotherapy

Answer 20

T

Question 21

what is a static microbial agent vs a cidal microbial agent

Answer 21

“Static” = stops growth
“Cidal” = kills

Question 22

what are the things that affect germicidal chemicals

Answer 22

• Time of exposure
• Temperature of environment (less effective at lower temps)
• Concentration of germicide (higher is usually better)

Question 23

How can we tell if a microbe is susceptible

Answer 23

Looking for “zone of clearing” - preventing growth in the medium
- Susceptibility - weather or not it kills microbe

Question 24

in the microbial death curve At time 0 minutes there are ____ cells. As time passes, ____ of the population dies each interval, So every 5 minutes, the population drops_____(one log reduction). Every 0 in the ________ adds a ____to the percentage when looking at the D-value

Answer 24

10 billion
90%
10×
microbe count
9

Question 25

what is Antagonism and Additive or synergistic microbial cocktails

Answer 25

Antagonism: negates the effect Additive or synergistic: adds or multiplies the effect

Question 26

what is an antibiotic

Answer 26

- Chemical substances that kill bacteria or prevent bacterial growth - A chemical not a protein

Question 27

what are 3 sources of microbes

Answer 27

○ Naturally produced by soil microbes ○ Some are completely synthetic chemicals ○ Some are “semi-synthetic” chemicals

Question 28

what are 3 characteristic of antibiotics

Answer 28

selectively toxic spectrum of activity Cidal vs static

Question 29

what are 5 targets of antibiotics

Answer 29

○ Plasma memb ○ Cell wall ○ Metabolic pathways ○ Ribosomes ○ DNA and RNA synthesis

Question 30

how do antibiotics try to achieve selective toxicity

Answer 30

by targeting a process or structure that is unique to bacteria

Question 31

what are the 5 ways antibiotics work

Answer 31

- Block DNA or RNA synthesis 2. Block protein synthesis 3. Inhibit bacterial metabolic pathways 4. Disrupt bacterial cell membranes 5. Block peptidoglycan synthesis

Question 32

what are 2 adverse affects of antibiotics

Answer 32

- toxicity/ intolerance - allergic reactions (True allergy (anaphylaxis) is probably rare, confusion between allergy and intolerance) - Disruption of “normal flora” Antibiotics (esp. broad spectrum) kill the “normal” microbiota

Question 33

why is selective toxicity difficult in fungi

Answer 33

theyre eukaryotic

Question 34

TF there are a wide array of antifungal agents

Answer 34

F, limited number

Question 35

what are some methods of action of antifungal agents

Answer 35

inhibit cell wall synthesis (chitin) inhibit microtubules and cell division

Question 36

if it works for fungi it _________ for bacteria and vise versa

Answer 36

doesnt work

Question 37

what is the problem with selective toxicity in antiviral agents

Answer 37

relatively few agents and fewer are truly “broad-spectrum” * Most work only against a specific virus

Question 38

TF all antiviral agents are Cidal

Answer 38

F, static

Question 39

TF most viruses arent treatable

Answer 39

T

Question 40

what are the challenges of antiviral therapy

Answer 40

○ Toxicity in humans ○ Don’t work against latent viruses ○ Treatment more effective if given early ○ Resistance develops quickly ○ Developing new agents is difficult

Question 41

antiviral agents can prevent viral adsorption or ________, prevent _______ of viral NA, block viral gene __________& ___________, block final viral _______________.

Answer 41

penetration un-coating expression and replication assembly &/or release

Question 42

what is antimicrobial resistance

Answer 42

Reduced ability of an antimicrobial agent to neutralize a microbe that was previously sensitive

Question 43

what are 5 mechanisms of antibiotic resistance

Answer 43

- E-flux pump = immediately pump out or prevent entry of antibiotic - Direct breakdown of antibiotic by bacterial enzymes - Modify the target on which the antibiotic acts (point mutation) - Target amplification: more copies, need more antibiotics - Target mimicry: act as a decoy to bind antibiotics - Enzymatic bypass: redundancy in processes

Question 44

what is Antimicrobial Susceptibility Testing

Answer 44

Determine the lowest concentration needed to kill or inhibit growth of a bacteria This is called the “MIC” (or Minimal Inhibitory Concentration)

Question 45

High MIC value =

Answer 45

a lot of antibiotic needed (suggest resistance)