Chapter 13: Sterilization/Disinfection, Antibiotics

Question 1

variables that dictate the most appropriate antimicrobial strategy used

Answer 1

type of microbe, number of microbes, risk of infection, object being sterilized/disinfected

Question 2

most resistant microbes

Answer 2

prions, endospores

Question 3

moderately resistant microbes

Answer 3

mycobacteria, non-enveloped viruses

Question 4

moderately susceptible microbes

Answer 4

gram-negative bacteria, eukaryotes

Question 5

most susceptible microbes

Answer 5

gram-positive bacteria, enveloped viruses, mycoplasmas

Question 6

process (chemical or physical) by which ALL living cells, spores, and viruses on an object are destroyed

Answer 6

sterilization

Question 7

chemical agent used to sterilize

Answer 7

sterilant

Question 8

killing or removal disease-producing organisms from inanimate surfaces (chemical or physical)

Answer 8

disinfection

Question 9

chemical used on inanimate objects to disinfect

Answer 9

disinfectant

Question 10

killing or removal of most pathogens from living tissues (most often chemical), does not always result in sterilization

Answer 10

antisepsis

Question 11

chemical used to remove/eliminate pathogens from living tissue

Answer 11

antiseptic

Question 12

reduces the microbial population to safe levels, usually involves cleaning, not complete removal of pathogens

Answer 12

sanitation

Question 13

agents with antimicrobial chemicals that kill microbes

Answer 13

cidal agents

Question 14

agents with antimicrobial chemicals that inhibit/control growth

Answer 14

static agents

Question 15

antimicrobial measures can typically affect _______________ as well

Answer 15

nonpathogenic microbes

Question 16

microbes die at an _____________ rate in the presence of killing agents

Answer 16

exponential

Question 17

measures efficacy of disinfecting and sterilizing agents, time it takes to kill 90% of the population, important to measure effectiveness of a disinfectant or antimicrobial

Answer 17

decimal reduction time (D-value)

Question 18

uses high pressure and high temp to sterilize objects, sufficient for destroying endospores after 20 mins, ex: autoclaves, pressure cookers, bench top sterilizers

Answer 18

pressurized steam sterilization

Question 19

biohazardous waste is destroyed by burning, for single-use items only

Answer 19

incineration

Question 20

for moisture-sensitive items, not as effective as steam sterilization but can sterilize if done correctly

Answer 20

dry oven

Question 21

kills most organisms and viruses, but NOT for spores or hyperthermophiles

Answer 21

boiling (100C)

Question 22

heating of food at a temp and time combination that kills pathogens, cannot eliminate all microorganisms and spores, goal is to kill pathogens without affecting texture, color, or taste of food

Answer 22

pasteurization

Question 23

all pharmaceutical drugs must be safe, but some are sensitive to heat or chemical sterilization

Answer 23

filtration

Question 24

sterilization can be performed through filtration where solutions are passed through filters with _________ (0.2um removes all cells, 0.02um removes viruses)

Answer 24

tiny pore size

Question 25

food is bombarded with high-energy electromagnetic radiation; viruses, endospores, and prions are very resistant to this method because they are very small

Answer 25

irradiation

Question 26

factors that influence the efficacy of a chemical disinfectant

Answer 26

presence of organic matter, kind of organisms present, corrosiveness, stability, odor, and surface tension

Question 27

presence of organic matter: chemicals bind to any organic material present, lowering _________ of agent against microbes

Answer 27

effectiveness

Question 28

kinds of organisms present: should be effective against a broad range of _________

Answer 28

pathogens

Question 29

corrosiveness: disinfectant should not damage the _________

Answer 29

surface it is on

Question 30

stability, odor, and surface tension: chemical should be ______ when stored, ________ odor, ______ surface tension to access cracks

Answer 30

stable; neutral/pleasant; low

Question 31

drug that slows/inhibits bacterial growth, effective therapy that reduces bacterial burden until it can be cleared by the host

Answer 31

bacteriostatic drug

Question 32

drug that kills bacteria cells

Answer 32

bactericidal drug

Question 33

antibiotic that targets one or limited groups of bacteria, pathogen must be identified before use (may take time), less disruption to normal microbiota

Answer 33

narrow spectrum antibiotic

Question 34

antibiotic that targets large groups of bacteria, used when treatment is urgent before the pathogen can be identified, can lead to disruption of the host microbiota

Answer 34

broad spectrum antibiotic

Question 35

we don't use broad spectrum antibiotics for every bacterial infection because it can lead to _________ of the hosts's normal microbiota and contribute to the development of ____________

Answer 35

disruption; antimicrobial resistance

Question 36

factors that health care providers need to consider when administering an antimicrobial drug

Answer 36

tissue distribution, excretion, and metabolism of drugs, allergies/other health concerns, half life of drugs

Question 37

effect where one drug inhibits the function of another

Answer 37

antagonistic effect

Question 38

effect where two drugs work better together than their additive effects

Answer 38

synergistic effect

Question 39

ability to kill/inhibit the infecting organism without damaging the host, difficult to achieve to minimize host side effects, goal of antimicrobial therapy

Answer 39

selective toxicity of a drug

Question 40

concentration of drug needed to completely inhibit bacterial growth in culture, lower = more effective antibiotic

Answer 40

minimum inhibitory concentration (MIC)

Question 41

tests a bacterial culture for susceptibility to antibiotics on a plate; the zone of inhibition of bacterial growth is assessed to determine the susceptibility of pathogens to various antibiotics

Answer 41

disk diffusion assay (Kirby-Bauer disk susceptibility test)

Question 42

mechanisms of antibacterial activity

Answer 42

metabolic inhibitors DNA replication inhibitors RNA polymerase inhibitors protein synthesis inhibitors cell membrane damage cell wall inhibitors

Question 43

drug that targets the unique ergosterol membrane or DNA synthesis

Answer 43

antifungal drug

Question 44

fungi have efficient _______________ that further complicate antifungal development

Answer 44

drug detoxification systems

Question 45

drug that targets metabolic functions

Answer 45

antiprotozoal drug

Question 46

_____________ can be used by protozoa (single-cell eukaryotes) for metabolism releasing free radicals that damage the parasite

Answer 46

nitroimidazoles

Question 47

general strategies for bacteria to resist antibiotics

Answer 47

1. prevent intracellular accumulation: destroy antibiotic, pump the antibiotic out, reduce membrane permeability (prevent entry of antibiotic) 2. prevent antibiotic binding to target: alter the target, modify the antibiotic (B-lac) 3. dislodge the ribosome: protect the ribosome (target for antibiotics)

Question 48

acquired resistance due to inherent characteristics of the organism

Answer 48

innate (intrinsic) resistance

Question 49

examples of innate resistance of antibiotics

Answer 49

gram-negative bacteria have an outer membrane that prevents entry; mycobacterium have a waxy mycolic acid cell wall, grow slowly, and can grow inside of host cells

Question 50

drug resistance that arises through genetic changes through mutations or acquisition of new genes

Answer 50

acquired resistance

Question 51

transfer of genes between neighboring cells, responsible for generation of multi-drug resistant bacteria

Answer 51

horizontal gene transfer

Question 52

How does horizontal gene transfer affect antibiotic resistance of otherwise-susceptible bacteria when antibiotics are misused?

Answer 52

An antibiotic susceptible pathogen can infect the lungs to cause pneumonia, pathogen replicates and a spontaneous antibiotic resistant mutant arises Patient is given antibiotic (selective pressure), susceptible bacteria dies but not the resistant ones Patient starts to get better then relapses, antibiotic-resistant bacteria start to replicate through HGT, patient risks transmitting the antibiotic-resistant strain to new person

Question 53

Why does antibiotic misuse lead to resistance?

Answer 53

If you take an antibiotic when you have a viral infection, the antibiotic attacks bacteria in your body. These are bacteria that are helpful or are not causing disease. This incorrect treatment can then promote antibiotic-resistant properties in harmless bacteria that can be shared with other bacteria