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Microbiology > Chapter 14 Study Guide > Flashcards

Chapter 14 Study Guide Flashcards

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Biology 101 flashcards
1
Q

Selectively finding and destroying pathogens without damaging the host

A

Selective toxicity

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2
Q

The goal is to have antimicrobial agent attack unique features of the pathogen leaving the hosts cells unaffected

A

Selective toxicity

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3
Q

Why is it generally more difficult to develop anti microbials for eukaryotic and viral infections

A

Similarity to host cells
Intracellular nature of viruses
Fewer unique targets
High mutation rates

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4
Q

What was the first anti microbial to be developed

A

Penicillin

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5
Q

Is better called anti microbial because it targets a wide range of microbes, including bacteria.

A

Penicillin

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6
Q

What is the difference between a synthetic and a semi synthetic drug ?

A

Synthetic is made in a lab or not found in nature

Semi synthetic is chemically modified derivative of a natural antibiotic

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7
Q

The first true antibiotic discovered was _______. It was discovered by ______.

A

Penicillin

Alexander Fleming

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8
Q

Cause reverse inhibition of growth, with bacterial growth restarting after elimination of the drug.

A

Bacteriostatic

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9
Q

Drugs kill their target bacteria

A

Bactericidal

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10
Q

A ______ targets only specific subsets of bacterial pathogens.

If the pathogen causing an infection has been identified, it is best to use ________.

A

Narrow spectrum antimicrobial

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11
Q

A __________ targets a wide variety of bacterial pathogens, including both gram positive and gram negative.

A

Broad spectrum

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12
Q

The risk associated with using broad spectrum antimicrobials that they will also target a broad spectrum of the normal microbiota, increasing the risk of a _________, a secondary infection in a patient having a preexisting infection.

A

Superinfection

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13
Q

A _______ develops when the antibacterial intended for preexisting infection kills the protective microbiota, allowing another pathogen resistant to the antibacterial to proliferate and cause a secondary infection.

A

Superinfection

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14
Q

What are the 5 main mechanisms of actions of antibiotics

A

Inhibit cell wall synthesis
Inhibit protein synthesis
Disruption of cell membrane
Inhibit nucleic acid synthesis
Inhibit metabolic pathways

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15
Q

Which of the 5 mechanisms of actions does penicillin use ?

A

Inhibit cell wall synthesis

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16
Q

Have a broader spectrum of effectiveness compared to penicillin. They can target a wider range of bacteria, including some gram negative bacteria.

A

Ampicillin and amoxicillin

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17
Q

Is a semisynthetic penicillin that was developed to address the spread of enzymes that were inactivating the other penicillins

A

Methicillin

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18
Q

Why is penicillin called a B-lactam antibiotic ?

A

It contains a B lactam ring that interferes with enzymes that bacteria use to build their cell walls

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19
Q

Examples of B lactam antibiotics

A

Penicillins
Cephalosporins
Monobactams
Carbapenems

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20
Q

A _______ enzyme breaks down the B lactam ring in B lactam antibiotics, rendering them ineffective against bacteria that produce this enzyme

A

B lactamase

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21
Q

Tetracyclines and erythromycin kill microbes by

A

Inhibiting protein synthesis

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22
Q

These drugs target bacterial ribosomes that have 70s ribosomes

A

Tetracycline and erythromycin

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23
Q

Fluoroquinolones like ciproflaxin, use the mechanism of ________?

A

Inhibition of nucleic acids

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24
Q

Inhibit folic acid synthesis

A

Sulfonamides

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25
Q

Is effective against a wide range of bacteria, including gram positive organisms found on the skin, such as staphylococcus and streptococcus

A

Bacitracin

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26
Q

Is effective against a wide range of bacteria, including gram positive organisms found on the skin, such as staphylococcus and streptococcus

A

Bacitracin

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27
Q

Why is targeting ergosterol in fungi effective for these kinds of infections ?

A

Ergosterol is similar to cholesterol, it maintains cell membrane integrity and function

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28
Q

Do human cells have ergosterol ?

A

No, this makes ergosterol a unique target for anti fungal drugs allowing selective toxicity

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29
Q

Should only be used for life threatening fungal infections because it can also bind to cholesterol, potentially causing kidney damage

A

Amphotericin B

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30
Q

What are some of the primary targets for anti viral medications ?

A

Block the receptor ps on the host cell that bind to the virus

Block fusion of the virus and cell

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31
Q

Specifically target influenza viruses by blocking the activity of influenza virus neuraminidase, preventing the release of the virus from infected cells.

A

Tamiflu
Relentza
Rapivab

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32
Q

Which pathogen are antiretroviral drugs used for ?

A

HIV

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33
Q

Also interferes with anaerobic bacteria

Treats trichomonas, giardiasis, and amebic dysentery

A

Metronidazole

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34
Q

Is when bacteria evolve to survive exposure to antibiotics that would normally kill them or stop their growth

A

Antibiotic resistance

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35
Q

What are the 4 most common mechanisms of antibiotic resistance

A

Blocking entry
Inactivation by enzymes
Alteration of target molecule
Efflux of antibiotic

36
Q

Three major ways to test for susceptibility to antimicrobials

A

Disk diffusion method
Broth dilution test
E-test

37
Q

The ______ establishes the MIC, determining the lowest concentration of an antimicrobial that inhibits visible bacterial growth

A

Broth dilution test

38
Q

Bacteria that are resistant to large number of antibiotics

A

Superbugs

39
Q

Are colloquially known as “superbugs” and carry one or more resistance mechanisms, making them resistant to multiple antimicrobials

A

MDR multi drug resistant microbes

40
Q

Why is there a concern ? Resistant to many common antibiotics, limiting treatment options

A

MRSA

41
Q

Resistant to vancomycin, a last resort antibiotics

A

VRE and VRSA

42
Q

Resistant to the most potent TB drugs, leading to longer, more complex treatments with a higher risk of failure.

A

MDR-TB and XDR-TB

43
Q

What are some potential safety issues associated with antimicrobial drugs ?

A

Allergy
Therapeutic index
Reactions of antibiotics with other drugs
Damage to organs
Risk to fetus

44
Q

The effect of two drugs together is greater than the effect of either alone

A

Synergism

45
Q

The effect of two drugs together is less than the effect of either alone

A

Antagonism

46
Q

The lowest concentration of drug that inhibits visible bacterial growth

A

MIC minimal inhibitory concentration

47
Q

The broth dilution test and the E test can determine the

A

MIC minimal inhibitory concentration

48
Q

Reports that record susceptibility of organisms encountered clinically

A

Antibiograms

49
Q

A substance produced by a microbe that, in small amounts, inhibits another microbe.

A

Antibiotic

50
Q

Synthetic substances that interfere with the growth of microbes

A

Antimicrobial

51
Q

The _______ antibacterials block the cross linking of pepetide chains during the biosynthesis of new peptidoglycan in the bacterial cell wall

A

B lactam drug

52
Q

Penicillins, cephalosporins, monobactams, and carbapenems all contain a B lactam ring, the site of attack by inactivating _________

A

B lactamase enzymes

53
Q

The use of chemicals to treat a disease

A

Chemotherapy

54
Q

Are a class of antibiotics used to treat various bacterial infections. They work by inhibiting bacterial DNA synthesis, effectively killing the bacteria.

Ex. Ciproflaxin and Levoflaxin

A

Fluoroquinolone

55
Q

Produced by viral infected cells to inhibit further spread of infection

A

Interferons

56
Q

Prevent the synthesis of peptidoglycan

A

Penicillins

57
Q

A scientist discovers that a soil bacterium he has
been studying produces an antimicrobial that
kills gram-negative bacteria. She isolates and
purifies the antimicrobial compound, then
chemically converts a chemical side chain to a
hydroxyl group. When she tests the antimicrobial
properties of this new version, she finds that this
antimicrobial drug can now also kill gram
positive bacteria. The new antimicrobial drug
with broad-spectrum activity is considered to be
which of the following?

A

semisynthetic

58
Q

Which of the following antimicrobial drugs is
synthetic?

A

sulfanilamide

59
Q

Which of the following combinations would most
likely contribute to the development of a
superinfection?

A

Long-term use of broad-spectrum antimicrobials

60
Q

Which of the following routes of administration
would be appropriate and convenient for home
administration of an antimicrobial to treat a
systemic infection?

A

oral

61
Q

Which clinical situation would be appropriate for
treatment with a narrow-spectrum antimicrobial
drug?

A

Treatment of strep throat caused by culture-identified Streptococcus pyogenes

62
Q

Which of the following terms refers to the ability
of an antimicrobial drug to harm the target
microbe without harming the host?

A

selective toxicity

63
Q

Which of the following is not a type of β-lactam
antimicrobial?

A

Glycopeptides

64
Q

Which of the following does not bind to the 50S
ribosomal subunit?

A

Tetracyclines

65
Q

Which of the following is not an appropriate
target for antifungal drugs?

A

cholesterol

66
Q

Which of the following drug classes specifically
inhibits neuronal transmission in helminths?

A

avermectins

67
Q

In the Kirby-Bauer disk diffusion test, the
_______ of the zone of inhibition is measured
and used for interpretation.

A

diameter

68
Q

Which of the following techniques cannot be used to determine the minimum inhibitory
concentration of an antimicrobial drug against a
particular microbe?

A

kirby bauer disk

69
Q

The utility of an antibiogram is that it shows
antimicrobial susceptibility trends

A

In a localized population.

70
Q

An ______ is used to show antimicrobial susceptibility trends in a specific, localized population, such as a hospital or community, helping guide empirical therapy and monitor resistance patterns within that area.

A

antibiogram

71
Q

Which of the following has yielded compounds
with the most antimicrobial activity?

A

soil

72
Q

Narrow-spectrum antimicrobials are commonly
used for prophylaxis following surgery.

A

false

73
Q

β-lactamases can degrade vancomycin.

A

false

74
Q

Echinocandins, known as “penicillin for fungi,”
target β(1→3) glucan in fungal cell walls.

A

true

75
Q

The rate of discovery of antimicrobial drugs has
decreased significantly in recent decades.

A

true

75
Q

If drug A produces a larger zone of inhibition
than drug B on the Kirby-Bauer disk diffusion
test, drug A should always be prescribed.

A

false

76
Q

The bacterium known for causing
pseudomembranous colitis, a potentially deadly
superinfection, is ________.

A

c. diff

77
Q

Selective toxicity antimicrobials are easier to
develop against bacteria because they are
________ cells, whereas human cells are
eukaryotic.

A

prokaryotic

78
Q

Antiviral drugs, like Tamiflu and Relenza, that are effective against the influenza virus by
preventing viral escape from host cells are called

A

neuraminidase inhibitors.

79
Q

Staphylococcus aureus, including MRSA strains,
may commonly be carried as a normal member
of the ________ microbiota in some people.

A

nasal microbiota

80
Q

The method that can determine the MICs of
multiple antimicrobial drugs against a microbial
strain using a single agar plate is called the
________.

A

E test

81
Q

Where do antimicrobials come from naturally?
Why?

A

bacteria and fungi;

82
Q

How does the biology of HIV necessitate the
need to treat HIV infections with multiple drugs?

A

high mutation rate

83
Q

What bacterial structural target would make an
antibacterial drug selective for gram-negative
bacteria? Provide one example of an
antimicrobial compound that targets this
structure.

A

The outer membrane of gram-negative bacteria is a key structural target for selective antibacterial drugs. An example of an antimicrobial compound that targets this structure is polymyxin B.

84
Q

inhibiting cell wall synthesis _____ prevent the synthesis of peptidoglycan

A

penicillin

85
Q

inhibiting protein synthesis– Target bacterial 70S ribosomes

A

Chloramphenicol, erythromycin, streptomycin,
tetracyclines

Microbiology (30 decks)

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