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BIMM 120 > Chapter 26 > Flashcards

Chapter 26 Flashcards

1
Q

What is sterilization

A

The killing or removal of ALL viable organisms

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2
Q

What is inhibition

A

Effectively limiting/inhibiting microbial growth. Ex. dehydration, refrigeration, freezing, etc

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3
Q

What is decontamination

A

Treatment of objects, surfaces, etc to make them clean and safe to handle

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4
Q

What is disinfection

A

Removal of all active pathogens, but not necessarily all microorganisms and not spores (dormant and not active)

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5
Q

What is widely used for killing microbes and why

A

Heat - high temperatures denatures macromolecules and DNA, which kills microbes

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6
Q

What is the decimal reduction time

A

The amount of time required to reduce viability tenfold, is determine in relation to the temperature and growth conditions

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7
Q

What can survive heat

A

Endospores and other types of spores can survive heat treatment that would normally kill vegetative cells

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8
Q

What is an autoclave

A

A device that uses steam under presure to produce 121C at 15 PSI, allows the termpature of water to get above 100C without evaporating

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9
Q

What are autoclaves used for

A

Used to sterilize both liquids and dry items

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10
Q

How long does it take to sterilize small volumes

A

About 15 minutes, it takes larger volumes more time because it takes longer to heat up large amounts

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11
Q

What is pasteurization

A

Precisely controlled heat and time to reduce the microbial load in heat-sensitive liquids, such as milk. It kills all pathogens in the product but does NOT kill all the normal microorganisms. It avoids the altering of product quality

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12
Q

What is used in radiation sterilization

A

Microwaves, UV, X-rays, gamma rays, and electrons can kill microbes. Exposing microbes to high enough energy can damage them to death

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13
Q

What is UV useful for

A

UV is useful for decontamination of surfaces because it can’t penetrate solid, opaque, or light-absorbing material

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14
Q

What is ionizing radiation

A

High energy electromagnetic radiation that produce ions and other reactive molecules that damage cell components, some microorganisms can be more resistant to this than others

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15
Q

What is filter filtration

A

Filtration avoids the use of heat on sensitive liquids and gases. The pores of filter are too small for organisms to pass through

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16
Q

What are depth filters

A

HEPA filters

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17
Q

What are membrane filters

A

Function more like a seive

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18
Q

What are the 3 possible antimicrobial agents

A

Bacteriostatic, bacteriocidal, and bacteriolytic

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19
Q

What is bacteriostatic

A

After adding the agent, the number of cells and number of viable cells have stopped increasing and is leveling off. They are still alive just not growing anymore

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20
Q

What is bacteriocidal

A

The cells are killed after the agent is added and the number of viable cells decrease while the number of cells stops increasing

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21
Q

What is bacteriolytic

A

An agent that will cause the cells to break apart (penicillin) as the cells grow. The cells will burst leading to the decline of the number of cells as well as the number of viable cells

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22
Q

What is minimum inhibitory concentration

A

MIC - is the smallest amount of an agent needed to inhibit growth of a microorganisms. It varies with the organism and its numbers as well as the abiotic factors such as temp, pH, and medium

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23
Q

Describe a disc diffusion assay

A

A antimicrobial agent is added to filter paper disc, which is then placed on a petri plate inoculated with a lawn of the test bacteria. The MIC is reached at some distance from the disc

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24
Q

What is the zone of inhibition

A

The area of no growth of the test bacteria around the disc, this zone can be measured and compared. Larger zone of inhibition means its more effective

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25
Q

Describe the antibiotic dilution series

A

Useful for determining the MIC. Have a set of tubes with broth that bacteria can grow in. Perform a series of serial dilutions of the antibiotic and putting dilutions in the broth. The first tube to show no microbial growth is most likely the dlution of MIC

26
Q

What are the two categories of chemical antimicrobial agents

A

Products used to control microorganisms in industrial applications and products designed to prevent growth of human pathogens in inanimate environments and body surfaces

27
Q

What are sterilants

A

Kills all microbes

28
Q

What are disinfectants

A

Kills most microbes but not all and not spores

29
Q

What are sanitizers

A

Reduce microbe levels considered safe

30
Q

What are antiseptics

A

Kill or inhibit microbes without harming the host

31
Q

What are important antiseptics

A

Alcohol, Phenol-containing compounds, Cationic detergents, Hydrogen peroxide, and Octenidine

32
Q

What does penicillin affect

A

Cell wall synthesis

33
Q

What is cirpoflaxin affect

A

DNA gyrase, is important because bacteria have it but humans don’t

34
Q

What is erythromycin affect

A

Ribosomal 50s subunit

35
Q

What do tetracyclines and streptomycins affect

A

Ribosomal 30s subunit

36
Q

What is selective toxicity

A

The ability to inhibit or kill a pathogen without affecting the host

37
Q

What are growth factor analogs

A

Are structurally similar to growth factors but are not functional. Can disrupt cell metabolism

38
Q

What are antibiotics

A

Naturally produced antimicrobial agents but less than 1% of antibiotics are clinically useful

39
Q

What are semisynthetic antibiotics

A

Antibiotics that have been modified

40
Q

What is the broad spectrum of antibiotics

A

Different bacteria vary in their sensitivity to antibiotics

41
Q

What are B-lactam antibiotics

A

They consist of over half of all antibiotics used worldwide. Includes penicillins and cephalosporins

42
Q

What is penicillin

A

Produced by fungi. Is primarily effective against G+ bacteria. It targets cell wall syntehsis by inhibiting transpeptidation by biding to transpeptidase enzymes

43
Q

What are aminoglycosides

A

They contain amino sugars bonded by glycosidic linkages

44
Q

What are some examples of (streptomyces) aminoglycosides. Streptomyces makes several antibiotics

A

Kanamycin, neomycin, and streptomycin

45
Q

What do aminoglycosides target in bacteria

A

They target the 30s ribosomal subunit to inhibit protein synthesis

46
Q

Why are they aminoglycosides no longer used today

A

Neurotxicity and nephrotoxicity

47
Q

What are macrolides

A

Broad-spectrum of antibiotic that targets the 50s ribosomal subunit of ribosome Ex. Erythromycin

48
Q

What are tetracyclines

A

Broad-spectrum inhibitom of protein synthesis by inhibiting the function of 30s ribosomal subunit of ribosome

49
Q

What is antimicrobial drug resistance

A

The acquired ability to resist the effects of a chemotherapeutic agent, can result from the mutation of bacterial gene

50
Q

What is an example of a mutation that could lead to antimicrobial drug resistance

A

A mutation that encodes for the ribosomal protein that alters the antibiotic binding site without altering the protein’s function. Can also result from acquiring a foreign gene

51
Q

What are the 6 reasons that microorganisms can be resistant to certain antibiotics

A
  1. WT lacks target that the antibiotic inhibits
  2. WT is impermeable to antibiotic
  3. Evolve change in the target of the antibiotic (mutation to produce resistance)
  4. Evolve a resistant biochemical pathway (bypass targeted pathway
  5. Acquired gene to inactivate or degrade the antibiotic
  6. Acquire gene to pump out the antibiotic
52
Q

Describe antibiotic inactivation by modification or cleavage

A

Antibiotics can have certain functional groups attacked that render it inactive

53
Q

Where are drug-resistance genes located

A

On the R plasmid or sometimes on transposon that jumped into the R plasmid

54
Q

Where do R plasmids originate

A

R plasmids predate the human use of antibiotics, originally evolved in soil bacteria and were used as a defense against bacteria and fungi that produce antibiotics

55
Q

What happens when antibiotics are overused

A

The wide-spread use of antibiotics selects for the evolution and spread of R plasmids.

56
Q

How do you minimize resistance to antibiotics in bacteria

A

By using antibiotics correctly and only when needed

57
Q

What can happen to the R plasmid over time in a population

A

Resistance to an antibiotic can be lost in a population if the antibiotic is not used for several years, carrying an unnecessary plasmid or gene is a burden and selected against

58
Q

What is bacteriophage therapy

A

The use of bacteriophage to kill pathogenic bacteria

59
Q

What are sulfa drugs

A

Inhibit synthesis of folic acid

60
Q

What are nucleic acid base analogs

A

Formed by addition of bromine or fluorine, block nucleic acid synthesis

61
Q

What are quinolones

A

Interfere with DNA gyrase. Ex. ciproflaxin

BIMM 120 (17 decks)

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