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LSCI230 > Week7C1 : Control of microorganisms > Flashcards

Week7C1 : Control of microorganisms Flashcards

1
Q

What is sterilization?

A

The killing or removal of all viable organisms (including

endospores).

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2
Q

What is inhibition?

A

Effectively limiting microbial growth.

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3
Q

What is decontamination?

A

The treatment of an object to make it safe to handle.

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4
Q

What is desinfection?

A

Directly targets the removal of all pathogens, not necessarily all microorganisms

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5
Q

What is the most widely used method for controlling microbial growth?

A

heat treatment.

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6
Q

What are the three physical methods?

A

heat
filtration
radiation

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7
Q

What are the three antimicrobials used internally

A

antibiotics
antifungal
antivirals

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8
Q

T or F : The time necessary to kill a defined fraction is independent of the initial cell concentration.

A

true

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9
Q

T or F : The D is not dependant on the population size while the TDT is

A

true

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10
Q

Sterilization is acheived by ___ minutes at ___˚C

A

10-15 minutes

121˚C

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11
Q

T or F : pasteurization kills listeria monocytogenes

A

false, it reduces the microbial load.

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12
Q

Flash pasteurization is ____ ˚C for ___ seconds

A

72 ˚C

15 seconds

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13
Q

bulk pasteurization is ____ ˚C for ___ minutes

A

65˚C

30 minutes

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14
Q

How does heat kills

A

denature proteins

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15
Q

How does radiation kills

A

breaks DNA so inhibit replication

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16
Q

What microorganism can resist an elevated level of radiation

A

deinoccoccus radiodurans

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17
Q

What are the two types of filters

A
  1. depth filters

2. memrbane filters

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18
Q

What are the three clases of antimicrobial agents?

A
  1. bacteriostatic
  2. bacteriolytic
  3. bacteriocidal
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19
Q

What is the only type of microbial agent that reduces the total number of cells and the total number of viable cells

A

bacteriolytic

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20
Q

When the total cell count and the viable cell count are not decreased, the antimicrobial agent is ___

A

bacteriostatic

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21
Q

When the total cell count is not decreased but the total viable count is decreased, the antimicrobial agent is ___

A

bacteriocidal

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22
Q

What is the MIC?

A

minimum inhibitory concentration : the smallest amount of an agent that will inhibits the growth

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23
Q

What is the MLC?

A

minimum lethal concentration (MLC) : lowest concentration of an agent that kills a test organism

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24
Q

What is the MBC?

A

minimum bacteriocidal concentration. It is the lowest concentration of agent that kills a test bacterium.

25
Q

On a disc diffusion assay, the line delimiting the zone of microbial growth and the zone of no microbial growth is the ____

A

MIC

26
Q

Name the four types of chemical antimicrobial agents for external use

A
  1. sterilants
  2. disinfectants/sanitizers
  3. antiseptics
  4. antimicrobial drugs
27
Q

What is the only type of external antimicrobial agent that kills endospores

A

sterilants

28
Q

What are the different antimicrobial drug classes

A
  1. antibiotics
  2. antifungal
  3. antiviral
29
Q

Disinfectants/Sanitizers are applied to ___

A

applied to nonliving objects or surface (can be toxic for

animals/humans).

30
Q

Antiseptics are applied to_____

A

surface of living tissues or skin (must not be toxic for

animals/humans).

31
Q

**Sodium hypochlorite is a ___

A

sterilant, desinfectant and antiseptic

32
Q

Antimicrobial drugs can either be ___ or ___

A

bacteriostatic

bacteriocidal

33
Q

Only ___ and _____ (sterilants) can kill endospores

A

halogens and alkylating agents

34
Q

What are the various targets of antimicrobial drugs?

A
  1. cell wall synthesis
  2. folic acid metabolism
  3. cytoplasmimc membrane structure and function
  4. lipid biosynthesis
  5. Protein synthesis
  6. Protein synthesis (30s inhibitor)
  7. Protein synthesis (50s inhibitors)
  8. DNA directed RNA polymerase
  9. RNA elongation
35
Q

What was the name of the first antimicrobial drug?

A

salvarsan

36
Q

What are growth factors analogs?

A

structure similar to growth factors but can’t functinon in a cell

37
Q

What are the two types of growth factors analogs seen in class

A

sulfa drugs

isoniazid

38
Q

***Sulfanilamide is an example of a ____ and it is an analgoue of ____

A

growth factor analog (sulfa drug)

p-aminobenzoic acid

39
Q

Isoniazid is a growth factor effective against ____ that interferes with the synthesis of ____

A

mycobacterium

mycolic acid

40
Q

What are the three types of synthetic antimicrobial drugs seen in class

A
  1. growth factors analogs
  2. nucleic acid analogs
  3. quinolone
41
Q

Quinolones are antibacterial

compounds that interfere with ___

A

DNA gyrase (control DNA supercoiling).

42
Q

___ are one of the most important groups of antibiotics of all time discovered by alexander fleming

A

B-Lactams

43
Q

B-Lactams group includes :

A

penicillins, cephalosporins, and cephamycins.

44
Q

Penicillins are effective against gram ____ and they inhibits the ____

A

positive

cell wall synthesis

45
Q

What are the only two semisynthetic penicillin resistant to the enzyme b-lactamase

A

methicillin and oxacillin

46
Q

T or F : penicillin are named after the mold they are isolated from

A

true

47
Q

How does cephalosporins work

A

by inhibition of the cell wall synthesis

48
Q

How does the b-lactam inhibitis the cell wall growth

A

binds the TPase (important enzyme for the cross-linking of the peptidoglycan wall)

49
Q

the majority of antibiotics
we use came from the
bacteria ____
(80%)

A

streptomyces

50
Q

**Streptomycin is an _____

A

aminoglycoside

51
Q

***Streptomycin target the ______ and is bacterio___

A

target the 30s subunits and causes misreading of the mRNA

bacteriocidal

52
Q

What are the 4 antibiotics isolated from proxaryotes groups seen in class

A
  1. aminoglycosides
  2. chloramphenicol
  3. macrolides
  4. tetracyclines
53
Q

What is the target of chlorampehnicol?

A

binds the 23s rRNA and block peptide elongation

54
Q

Chlorampehnicol is bacterio___

A

static

55
Q

What is the target of macrolides

A

target the 50s subunit of the ribosome

56
Q

What is the target of tetracyclines?

A

inhibits the 30s ribosomal subunit

57
Q

Why are antiviral drugs more toxic than antibiotics

A

Most antiviral drugs also target host structures, resulting in toxicity

58
Q

Most successful and commonly used antivirals are the _____

A

nucleoside analogs

59
Q

***Fluconazole and nyastin inhibits ____

A

ergosterol synthesis

LSCI230 (20 decks)

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