Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

2) Introductory Microbiology COPY > Microorganism Control > Flashcards

Microorganism Control Flashcards

1
Q

What is sterilization?

A
  • Killing or removal of all viable organisms (including endospores)
  • All or nothing: either it is sterile or not
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is inhibition?

A

Effectively limiting microbial growth (ex: refrigerators)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is decontamination?

A

Treatment of an object to make it safe to handle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is disinfection?

A

Targets the removal of all PATHOGENS, not necessarily all microorganisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the 3 physical methods to control microorganism growth?

A

Heat, radiation, filtration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the chemical methods (antimicrobials) that are used on external surfaces? (4)

A
  • Sterilants
  • Disinfectants
  • Sanitizers
  • Antiseptics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the chemical methods (antimicrobials) that are used internally? (3)

A
  • Antibiotics
  • Antivirals
  • Antifungals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the most widely used method to control microbial growth?

A

Heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the decimal reduction time?

A

Amount of time required to reduce viability tenfold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is the decimal reduction time correlated to temperature?

A

Decimal reduction time is inversely correlated with the temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Does the initial cell concentration affect the time necessary to kill a defined fraction?

A

NO, since it is a fraction, not a number of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the thermal death time? What is it dependent on?

A
  • Time needed to kill all cells at a given temperature

- Dependent on the population size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What method is used to killed endospores?

A
  • Endospores resist boiling

- Autoclaving

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the pressure and temperature of autoclaving? How long does it take to sterilize?

A
  • 15 psi
  • 121oC
  • 10-15 minutes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is pasteurization?

A

Using precisely controlled heat to reduce the microbial load in heat-sensitive liquids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Is pasteurization a sterilization method?

A

No, since it does not kill all organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does pasteurization target? Why?

A
  • Targets pathogens (Listeria, salmonella, E. coli)

- Reduces the microbial load and increases the shelf life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the two types of pasteurization?

A
  • Flash pasteurization: 72oC for 15 seconds

- Bulk pasteurization: 65oC for 30 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What kind of radiation can reduce microbial growth?

A

Microwaves, UV, X-rays, gamma rays, and electrons, cathode ray tubes, X-rays, radioactive nuclides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does UV affect microorganisms?

A

Has sufficient energy to cause modifications and breaks in DNA, which inhibits replication, transcription and causes death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What can’t UV penetrate?

A

Solid, opaque, or light-absorbing surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is ionizing radiation? What does it generate?

A
  • Electromagnetic radiation that produces ions and other reactive molecules
  • Generates electrons and hydroxyl radicals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which microorganisms are good at resisting radiation?

A
  • C. botulinum (since they create spores)

- Viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does filter sterilization do?

A
  • Does not kill microorganisms

- Removes them from a solution or from the air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are depth filters? What does it sterilize?

A
  • Very thick
  • Fibrous sheet
  • Used to sterilize liquid, air
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are HEPA filters? What does it sterilize?

A
  • Depth filters

- Filtrates air and removes all microorganisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are membrane filters?

A
  • Piece of material in which holes are drilled

- ex: nucleation tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How can filtration speed be increased?

A

By a syringe, pump, or vacuum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are bacteriostatic antimicrobial agents?

A
  • Inhibits growth of microorganisms
  • Total cell count maintained
  • Viable cell count maintained
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are bactericidal antimicrobial agents?

A
  • Kills microorganisms
  • Total cell count maintained
  • Viable cell count decreased
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are bacteriolytic antimicrobial agents?

A
  • Kills microorganisms by inducing cell lysis
  • Total cell count decreased
  • Viable cell count decreased
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the minimum inhibitory concentration (MIC)?

A
  • The smallest amont of an agent needed to inhibit the growth of a microorganism
  • Varies with the type of organism, inoculum size, temperature, pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the minimum lethal concentration (MLC)?

A

The lowest concentration of an agent that kills a test organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the minimum bacteriocidal concentration (MBC)?

A

The lowest concentration of an agent that kills a test bacterium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the decimal reduction time (at concentration X)?

A

The time needed at concentration X to kill 90% of the population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the decimal reduction concentration (after x minutes)?

A

The concentration you need to kill 90% of the population in a period of 5 minutes

37
Q

What is the disc diffusion assay?

A

If microorganisms are affected by the antimicrobial disks, they will form zones of inhibition (areas with no growth)

38
Q

What are the functions of antimicrobials?

A
  • Prevent spreading of a pathogen
  • Prevent contamination of the host
  • Cure superficial bacterial infections
39
Q

What are the two types of antimicrobial products?

A
  • Products used to control microorganisms in commercial and industrial applications (paper, textile, fuel)
  • Products designed to prevent growth of human pathogens (sterilants, disinfectants, sanitizers)
40
Q

What are sterilants? Do they kill endospores?

A
  • Destroy all forms of microorganisms, including endospores

- Extremely toxic, also called cold sterilization

41
Q

What are disinfectants/sanitizers? Do they kill endospores?

A
  • Applied to non-living objects or surfaces (floors, tiles, etc.)
  • Can be toxic for animals/humans
  • Do NOT kill endospores
42
Q

What are antiseptics?Do they kill endospores?

A
  • Applied to the surface of living tissues or skin
  • Must not be toxic for animals/humans
  • Do NOT kill endospores
43
Q

What are antimicrobial drugs?

A
  • Antibiotics, antifungals, antivirals
  • Applied outside or inside the body of animals/humans
  • Must not be toxic for animals/humans
  • Do NOT kill endospores
44
Q

What kind of antimicrobial agent is alcohol? how does it function?

A
  • Disinfectant and/or antisepctic

- Dissolves lipids and proteins in the microorganisms, which kills them

45
Q

What kind of antimicrobial agent is sodium hypochlorite? how does it function?

A
  • Disinfectant, antiseptic, and sterilant (in high concentrations)
  • Used in hospitals
  • Chlorine oxidizes anything organic (lipids, RNA, DNA, peptidoglycan): destroys everything
46
Q

How do antimicrobial agents compare to antimicrobial drugs?

A

Agents: very unspecific
Drugs: extremely specific

47
Q

Antimicrobial drugs are classified based on what? (3)

A
  • Molecular structure
  • Mechanism of action
  • Spectrum of antimicrobial activity; the variability of species they can target (broad vs. specific)
48
Q

Why can antimicrobial drugs be used internally?

A

Low toxicity for the host, while there is high toxicity for the pathogens (minimum side effects)

49
Q

How do antimicrobial drugs target pathogens?

A

By targeting specific components that are only found in pathogens (ex: peptidoglycan, 70S ribosomes)

50
Q

Are antimicrobial agents bacteriostatic, bactericidal, or bacteriolytic?

A

Bacteriostatic or bactericidal

51
Q

What are examples of components of good antimicrobial drugs?

A
  • No severe side effects
  • Low risk/benefit ratio
  • Broad spectrum of activity to facilitate rapid medical intervention
  • Appropriate bioavailability and pharmacokinetics; must reach the site of infection
  • Low cost to develop and manufacture
52
Q

Who studied selective toxicity? When?

A
  • Paul Ehrlich

- Early 1900s

53
Q

What is selective toxicity?

A

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

54
Q

What is Salvarsan? What did it treat? Who discovered it?

A
  • One of the first antimicrobial drugs
  • Used to treat syphilis
  • Discovered by Paul Ehrlich
55
Q

What are growth factor analogs?

A
  • Structurally similar to growth factors, but do not function in a cell
  • Targets a metabolic pathway that is only present in the pathogen; not the host
56
Q

What are Sulfa Drugs? Who discovered them? Is it bacteriostatic, bactericidal, or bacteriolytic?

A
  • Antimicrobial drug
  • Gerhard Domagk (1930s)
  • Sulfanilamide is an analogue of p-aminobenzoic acid, which is needed to synthesize folic acid
  • Bacteriostatic: inhibits folic acid synthesis
57
Q

What is Isoniazid?

A
  • Antimicrobial drug
  • Growth analog effective only against Mycobacterium
  • Interferes with the synthesis of mycolic acid, which is necessary for their cell wall
  • The immune system can then kill the bacterium
58
Q

What are Nucleic Acid Base Analogs?

A
  • Antimicrobial drug
  • Formed by the addition of bromine or fluorine
  • Stops DNA replication/translation
59
Q

What are quinolones? Is it bacteriostatic, bactericidal, or bacteriolytic?

A
  • Antimicrobial drug
  • Antibacterial compounds that inhibit DNA gyrase (control DNA supercoiling)
  • Gyrase relaxes and un-twists DNA; if it is missing, the DNA coils can break from the tension
  • Bacterium cannot replicate its DNA
  • BACTERICIDAL
60
Q

What are antibiotics?

A

Antimicrobial agents naturally produced by a variety of bacteria and fungi to inhibit or kill other microorganisms (to eliminate competition)

61
Q

What is the most important group of antibiotics? What are its 3 components?

A
  • B-Lactams
  • Penicillins
  • Cephalosporins
  • Cephamycins
62
Q

Who discovered Penicilins? From what?

A
  • Alexander Flemming

- Isolated from mold

63
Q

What are penicilins effective against? What is their function?

A
  • Primarily against Gram-Positive bacteria since the outer wall of Gram-Negative bacteria limits the transport of penicilin
  • Inhibit cell wall synthesis by targeting peptidoglycan
64
Q

What are cephalosporins made from? What does their mode of action ressemble? What is it used to treat?

A
  • Produced by a fungus
  • Same mode of action as penicillins
  • Commonly used to treat gonorrhea
65
Q

What is the mode of action of B-Lactams?

A
  • Transpeptidase catalyzes transpeptidation in peptidoglycan
  • Transpeptidase will bind to the B-Lactam, and will be inhibited
  • The bacterium will have holes in its cell walls, and is more susceptible to osmotic shock, which can cause cell lysis
66
Q

Are B-Lactams bacteriostatic, bactericidal, or bacteriolytic?

A
  • Bactericidal or bacteriolytic

- Bacteriostatic in isotonic solutions

67
Q

How do B-Lactams cause cell lysis?

A

The bacterium is more susceptible to osmotic shock (due to holes in cell walls), which can cause cell lysis

68
Q

What is the function of aminoglycosides? Is it bacteriostatic, bactericidal, or bacteriolytic?

A
  • Antibiotic from Prokaryotes
  • Targets the 30S subunit of ribosomes, and causes misreadings of mRNA (makes weird proteins)
  • Bactericidal
69
Q

What is the function of chloroamphenicols? Is it bacteriostatic, bactericidal, or bacteriolytic?

A
  • Antibiotic from Prokaryotes
  • Binds to 23S rRNA and blocks peptide elongation
  • Bacteriostatic, which becomes bactericidal over time
70
Q

What is the function of macrolides? Is it bacteriostatic, bactericidal, or bacteriolytic?

A
  • Antibiotic from Prokaryotes
  • Broad-spectrum antibiotics that target the 50S subunit of ribosomes
  • Bacteriostatic
71
Q

What is the function of tetracyclines? Is it bacteriostatic, bactericidal, or bacteriolytic?

A
  • Antibiotic from Prokaryotes
  • Broad-spectrum, which inhibits 30S ribosomal subunits and blocks protein synthesis
  • Bacteriostatic
72
Q

What is the function of daptomycin? Is it bacteriostatic, bactericidal, or bacteriolytic? What is it used for? Where is it produced from?

A
  • Antibiotic from Prokaryotes
  • Produced from Streptomyces
  • Used to treat Gram-Positive bacterial infections
  • Forms pores in the cytoplasmic membrane; loses permeability and PMF function
73
Q

What is the function of platensimycin? Is it bacteriostatic, bactericidal, or bacteriolytic?

A
  • Antibiotic from Prokaryotes

- Broad-spectrum, effecting against MRSA and vancomycin-resistant enterococci

74
Q

Why are antibiotic producers tolerant? (3)

A
  • Lack target sites (ex: no peptidoglycan)
  • Modify target sites
  • Lack of uptake mechanism
75
Q

What are the 4 antibiotic resistance mechanisms?

A
  • Destruction or modification of the antibiotic
  • Modification of the target site
  • Modification of the uptake mechanism
  • Efflux pumps
76
Q

What are efflux pumps?

A
  • Transporter that takes something out of the cell

- Antibiotic resistance mechanism

77
Q

What is the acquisition of resistance mediated by?

A

By the acquisition of a new gene (or group of genes) that provide the cells with a new function (i.e. antimicrobial resistance)

78
Q

Most drug-resistant bacteria isolated from patients contain drug-resistant genes located on ____________

A

R plasmids

79
Q

Can R plasmids be transferred?

A

R plasmids can be transferred between bacteria of the same species or related species

80
Q

Which pathogen has developed resistance to all known antimicrobial agents?

A

Methicillin-resistant S. aureus (MRSA)

81
Q

How can antimicrobial drug resistance be minimized?

A

By using antibiotics correctly and only when needed (reduce selection)

82
Q

How do antiviral drugs result in toxicity? Why?

A
  • Most antiviral drugs target host structures

- Viruses use host cell machinery

83
Q

Are antibiotics useful for viruses?

A

No, they are ineffective

84
Q

What are the most successful and commonly used antivirals?

A
  • Nucleoside analogs

- Block reverse transcriptase and production of DNA (RNA viruses)

85
Q

What are protease inhibitors?

A
  • Antiviral Drugs

- Inhibit the processing of large viral proteins into individual components

86
Q

What are fusion inhibitors?

A
  • Antiviral Drugs

- Prevent viruses from successfully fusing with the host cell

87
Q

Why do Fungi pose problems for chemotherapy?

A
  • Since they are Eukaryotes

- Much of the cellular machinery is the same as that of animals and humans

88
Q

What do antifungal drugs target?

A
  • Ergosterol synthesis

- Cell wall synthesis (inhibitor of chitin)

2) Introductory Microbiology COPY (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions