Pharmacology - Antibiotics Part 1 (Exam 2) Flashcards

1
Q

Who discovered the world’s first antibiotic

A

Alexander Fleming

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2
Q

3 things to know from antibiotics table

A

1) most antibiotics derived from a natural product
2) development is NOT continuous
3) as bacteria develop resistance, people develop new antibiotics

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3
Q

chemical derived from microorganisms (commonly yeasts and fungi) and used to inhibit other microorganisms (generally, a drug used for bacterial infections).

A

antibiotic

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4
Q

stop growth/reproduction with no cell killing

A

bacteriostatic

(STOP)

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5
Q

stop growth/reproduction AND cell killing

A

bactericidal

(KILL)

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6
Q

stop growth/reproduction AND cell killing/destruction

A

bacteriolytic

(DESTROY)

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7
Q

Differences between gram + and gram - bacteria

A

Gram +: thick peptidoglycan layer, stains purple, anaerobes found in oral cavity, no outer envelope

Gram -: thin peptidoglycan layer, stain pink, outer envelope

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8
Q

What factors play a role in the likelihood of a microorganism to cause an infection?

A
  1. Infectivity (ability of the bacteria to infect the host)
  2. # of organisms present (wash your hands)
  3. Immunity of host (pt. may be immunosuppressed)
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9
Q

Which antibiotics affect the cell wall?

A

Penicillins
Cephalosporins

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10
Q

Which antibiotics affect the plasma membrane?

A

Daptomycin

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11
Q

Which antibiotics affect DNA synthesis?

A

Fluoroquinolones

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12
Q

Which antibiotics affect metabolic pathways?

A

Sulfonamides
Trimethoprim

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13
Q

Which antibiotics affect ribosomes?

A

Tetracyclines (30S subunit)
Macrolides (50S subunit)

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14
Q

Name 5 mechanisms of action of antibiotics

A

1) inhibit cell wall synthesis
2) alteration in cell membrane integrity
3) inhibition of ribosomal protein synthesis
4)inhibition of nucleic acid synthesis
5)inhibition of folic acid synthesis

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15
Q

How does inhibition of cell wall synthesis work?

A

-Beta-lactam antibiotics covalently bind to active site of penicillin-binding proteins (PBP)
-These PBP remove the terminal alanine, this will allow for formation of the cross-linked peptidoglycan wall
-Binding inhibits the transpeptidase rxn and halts peptidoglycan synthesis and the cell dies

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16
Q

Name of rxn that halts peptidoglycan synthesis

A

transpeptidation

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17
Q

Another name for peptidoglycan

A

murein

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18
Q

Peptidoglycan is made of repeated subunits of?

A

N-acetylglucosamine and N-acetylmuramic acid bound by B(1,4) linkages

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19
Q

Peptidoglycan is cross linked via?

A

short peptides

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20
Q

Binding to the cell membrane is ____________ dependent insertion of its lipid tail

A

calcium

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21
Q

After binding to the cell membrane via calcium dependent insertion of lipid tail, what happens?

A

depolarization
K+ efflux
rapid cell death

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22
Q

Protein-making factory

A

ribosome

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23
Q

Different _________ work together to make _______ possible

A

proteins; life

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24
Q

Which drugs target the 50S prokaryotic subunit (bacterial) and 39S eukaryotic subunit (mitochondrial)?

A

erythromycin + chloraphenicol

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25
Q

Which drugs target the 30S prokaryotic subunit (bacterial) and 28S eukaryotic (mitochondrial) subunit?

A

tetracycline + glycylcline

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26
Q

Prokaryotic –> Bacterial (_____S)

It is made up of _____S and ______S subunits

A

70S

50S and 30S subunits

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27
Q

Eukaryotic –> Mitochondrial (_____S)

It is made up of ______S and ______S subunits

A

55S

39S and 28S

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28
Q

Eukaryotic –> Cytosolic/on rough ER (_____S)

It is made up of ______S and ______S subunits

A

80S

60S and 40S

29
Q

How does inhibition of nucleic acid synthesis occur?

A

DNA-dependent RNA polymerase

30
Q

Antibiotics inhibiting folic acid synthesis also suppress?

A

DNA synthesis

31
Q

T/F: all microbial resistance patterns are broad

A

False! They’re local bc the antibiotics are based on a particular community

32
Q

Name some methods for reducing bacteria resistance

A

-education
-improved hand washing technique
-better hospital infection control
-isolation of patients w/ highly resistant bacteria
-control of antibiotic use in hospitals
-discontinued use of antibiotics in agriculture

33
Q

Mechanisms by which bacteria become resistant to drugs (6)

A
  1. Modification of target sites
  2. Alternate growth requirements
  3. Enzymatic activation
  4. Overproduction of target sites
  5. Efflux pumps
  6. Decrease in cell permeability
34
Q

Very common mechanism of bacterial resistance

A

enzymatic inactivation

35
Q

What enzyme hydrolyzes penicillins and cephalosporins?

A

B-lactamase

36
Q

Which enzyme inactivates chloramphenicol, aminoglycosides, and tetracyclines?

A

acetyltransferases

37
Q

How do bacteria alter target sites?

A

-ribosomal point mutations
-altering DNA gyrase & topoisomerase
-modifying penicillin-binding proteins in viridians group streptococci & pneumococci

38
Q

How do bacteria alter cell wall permeability? Is this a good method?

A

-limiting access of antibiotic to receptor by deleting outer membrane proteins or closing membrane pore channels

Nope, low level of resistance (must be combined with another mechanism)

39
Q

What is the purpose of efflux pumps?

A

eliminating antibiotics (already in cell) from cell interior as fast as they can enter

40
Q

How many families are there of efflux transporters?

A

5

41
Q

bacteria develop alternative metabolic growth requirements to evade destruction

A

auxotrophy

42
Q

Requirement of a specific growth substance beyond the minimum required by the wild type/parent strain for normal metabolism and reproduction.

Give an example

A

auxotrophy; enterococci

43
Q

This acid develops sulfonamide resistance?

A

Para-aminobenzoic acid

44
Q

How is there overproduction of targets by B-lactamase?

A

resistance to B-lactam antibiotics

45
Q

antibiotic no longer kills the microorganism, but it merely inhibits its growth or multiplication (growth after drug removal)

A

tolerance

46
Q

multiplication in the presence of the antibiotic

A

resistance

47
Q

Antibiotic resistance is characterized by a higher _______

A

MIC = minimum inhibitory concentration

48
Q

minimum duration for killing of 99% of bacterial cells in the population versus susceptible bacteria

A

MDK99

49
Q

What does a lower MDK99 indicate?

A

bacteria is susceptible

50
Q

Tolerance is caused by loss of ______ activity. There is a mutation in the _____________ system controlling the bactericidal autolysin activity

A

autolysin; sensor-response

51
Q

Resistance occurs with what kind of doses?

A

subtherapeutic antibiotic doses

(does not kill/inhibit the microorganism)

52
Q

In resistance, _________ microorganisms are inhibited, allowing resistant ones to multiply and dominate

A

sensitive

53
Q

In resistance, the antibiotic is considered a _________ to survival. The microorganism reacts by which 3 things?

A

threat

  1. mutation to resistance
  2. acquisition/transfer of resistance genes
  3. expression of latent resistance genes
54
Q

Three mechanisms of horizontal gene transfer

A
  1. transduction
  2. conjugation
  3. transformation
55
Q

Name some mobile genetic elements involved in horizontal gene transfer

A

naked DNA
plasmids
bacteriophages
transposons
integrons

56
Q

Jumping genes

A

transposons

57
Q

self-transfer of genetic information by plasmids or transposons to other microorganisms

A

conjugation

58
Q

DNA from one bacterium to another by a bacteriophage intermediary

A

transduction

59
Q

naked DNA from their environment into their genome

A

transformation

60
Q

Name some genetic variations in bacteria

A

-local nucleotide changes in genome
-rearrangement of genomic sequences

61
Q

Name some adverse effects of antibiotic therapy

A

-allergies
-resistance
-superinfection
-nephrotoxicity
-ototoxicity
-antibiotic induced photosensistivity
-prolonged QTc interval
-possible interference w/ oral contraceptives

62
Q

drug deposited in the skin absorbs UV light and transfers energy to local tissue

A

phototoxicity

63
Q

sunlight causes haptens to become complete antigen to the skin; allergic rxn is immediate or delayed

A

photoallergy

64
Q

Antibiotics can ___________ the efficacy of oral contraceptives by __________ their clearance from the body

A

decrease; increase

65
Q

Some anti-coagulants act through inhibition of _______________ blood coagulation proteins.

Since gut bacterial flora produce majority of vitamin K, you could further ________ vitamin K production when taking antibiotics

A

vitamin K-dependent; decrease

(decreased vitamin K production = increased effect of Warfarin (anticoagulant) = excessive bleeding)

66
Q

T/F many antibiotics can be used during pregnancy

A

FALSE

67
Q

Which antibiotics are ok to use during pregnancy?

A

Penicillin
Erythromycin

68
Q

Which antibiotic is NOT ok to use during pregnancy?

A

Tetracycline