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Microbiology- HLSC 124 🦠 > Microbio Chapter 20- Antimicrobial Agents > Flashcards

Microbio Chapter 20- Antimicrobial Agents Flashcards

1
Q

What antimicrobial agents attack the cell wall?

A
  1. Penicillin
  2. Cephalosporins
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2
Q

What part of the cell wall do the agents attack?

A

P part of peptidoglycan layer

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3
Q

What do cell wall attacking agents cause

A

Osmotic lysis (cell dies)

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4
Q

What is the nucleus of Penicillin called?

A

Beta lactam ring

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5
Q

What two main types of penicillin?

A

a. Natural
b. Semisynthetic

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6
Q

What are the two types of natural penicillin?

A

PenG
PenV

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7
Q

How is PenG penicillin given?

A

Through injection

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8
Q

How is PenV penicillin given?

A

Taken orally

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9
Q

What are examples of semisynthetic penicillin?

A

Oxacillin, Ampicillin, Methicillin

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10
Q

What enzyme destroys the beta lactam ring of penicillin?

A

Penicillinase or Beta-lactamase

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11
Q

What are semisynthetic penicillin resistant to?

A

Penicillinase/beta lactamase. Resistance varies based on spectrum.

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12
Q

Example of a bacteria that produces Beta lactamase?

A

Staphylococcus aureus

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13
Q

Methicillin resistance?

A

Resistant
-MRSA strain (Methicillin resistant Staphylococcus aureus)

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14
Q

Oxacillin spectrum?

A

Narrow (only kill one group)

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15
Q

Ampicillin spectrum?

A

Broad (Could kill more bacteria)

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16
Q

What is a common adverse effect of penicillin?

A

Allergic reaction

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17
Q

What are cephalosporins resistant to?

A

Enzymes (e.g; Beta lactamase)

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18
Q

What is a problem associated with Cephalosporin manufacturing?

A

It is expensive because they require lab purification

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19
Q

How are the semisynthetic forms of cephalosporins named?

A

They are called by generation. 1st, 2nd, 3rd, 4th, 5th

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20
Q

What happens with each generation of semi forms of cephalosporins?

A

Each new generation gets broader and broader spectrum

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21
Q

What disease does 3rd gen cephalosporin treat?

A

Meningitis

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22
Q

What adverse effects are associated with Cephalosporins?

A

Mild GI tract symptoms

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23
Q

What antimicrobial agents inhibit protein synthesis?

A
  1. Chloramphenicol
    2.Erythromycin
    3.Streptomycin
    4.Tetracycline
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24
Q

Why is Chloramphenicol CHEAPER to manufacture?

A

It naturally has a simple structure so it is less expensive to synthesise it chemically

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25
Q

What does Chloranphenicol’s simple structure allow it to do?

A

More easily penetrate tissues like the BBB

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26
Q

What can Chloramphenicol’s treat?

A

Meningitis
-bc it can penetrate BBB

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27
Q

What is a rare adverse effect associated with Chloramphenicols?

A

Aplastic Anemia

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28
Q

What adverse effect can occur if a woman takes chloramphenicol while pregnant?

A

Grey baby syndrome

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29
Q

How does Chloramphenicol inhibit peptide bond formation?

A

It binds to the 50s portion of the ribosome

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30
Q

What family does erythromycin belong to?

A

Macrolides
-Macrocyclic lactone ring structure

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31
Q

What drug can erythromycin be used as an alternative for?

A

Penicillin
e.g; allergy

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32
Q

What form can erythromycin be administered as?

A

Syrup form
-easy to take (orally)

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33
Q

What kind of cell wall bacteria can erythromycin penetrate?

A

Gram-positive

34
Q

What adverse effect is associated with Erythromycin?

A

Mild GI tract symtoms (~2-3%)

35
Q

How does erythromycin inhibit mRNA movement?

A

Binds to 50s portion of ribosome

36
Q

When was Streptomycin discovered?

37
Q

What disease has a resistance for streptomycin?

A

Tuberculosis (TB)
-bc of resistance steptomycin is no longer used to treat TB

38
Q

What adverse effects are associated with streptomycin?

A

Deafness
Kidney failure

39
Q

How does Streptomycin cause mRNA to be misread?

A

Binds to 30s unit causing it change shape and become an aberrant protein

40
Q

What spectrum activity does Tetracycline have?

A

The broadest spectrum activity

41
Q

What is the name of the semisynthetic form of Tetracycline?

A

Doxycycline

42
Q

Where is Tetracycline added to?

A

Animal feed
(in food chain)

43
Q

What is tetracycline used to treat?

44
Q

What adverse effects are associated with Tetracycline?

A
  1. Destroys normal flora causing GI tract symptoms and a fungal superinfection
  2. Binds to calcium e.g teeth
45
Q

What adverse effects are associated with tetracycline use during pregnancy?

A

During pregnancy —> kidney/liver affected
Fetus—> develops abnormal skull

46
Q

How does tetracycline block the tRNA docking site?

A

Binds to the 30s portion of the ribosome

47
Q

How does chloramphenicol inhibit protein synthesis?

A

Inhibits formation of peptide bonds

48
Q

How does Erythromycin inhibit protein synthesis?

A

Inhibits mRNA movement

49
Q

How does Streptomycin inhibit protein synthesis?

A

mRNA is misread

50
Q

How does tetracycline inhibit protein synthesis?

A

Blocks tRNA docking site

51
Q

What antimicrobial agents inhibit nucleic acid synthesis?

A
  1. Rifampin
  2. Quinolone & fluoroquinolone
52
Q

How does Rifampin inhibit nucleic acid synthesis?

A

Inhibits RNA polymerase

53
Q

Example of a bacteria species treated with Rifampin?

A

Mycobacterium

54
Q

What adverse effects are associated with Rifampin?

A

Liver
Infection during pregnancy

55
Q

How do quinolones and fluroquinolones inhibit nucleic acid synthesis?

A

Inhibits DNA gyrase

56
Q

What are quinolones used to treat?

A

Shigellosis and UTIs

57
Q

What happens when fluoride is added to quinolone drugs?

A

becomes a fluoroquinolone –> Penetration increases
e.g Cipro

58
Q

What is an adverse effect associated with fluoroquinolone?

A

Affects cartilage and joints

59
Q

What antimicrobial agent attacks the plasma membrane?

A

Polymyxin B

60
Q

How does Polymyxin B injure the plasma membrane?

A
  1. Forms a pore in plasma membrane
  2. Cell contents leak out
61
Q

What is treated with Polymyxin B?

A

Pseudomonas infections (blue/green pus)

62
Q

What adverse effects are associated with Polymyxin B?

A

Toxic to kidneys

63
Q

How is Polymyxin B administered?

A

Only topical use (ointment)
-not systemic as it leads to nephrotoxicity

64
Q

What antimicrobial agents act as metabolites?

A
  1. Sulfa drugs
  2. Trimethoprim
65
Q

What action do metabolites take to kill a cell?

A
  1. Inhbit folic acid
  2. DNA/RNA can’t be synthesised
  3. Cell dies
    (is a competitive inhibitor)
66
Q

What can be treated by metabolites?

A

Cystitis (UTI)

67
Q

What adverse effects are associated with Sulfa drugs?

A

-During pregnancy–> 3rd trimester = neurological defects
-Jaundice
-Anemia
-Allergy

68
Q

What adverse effects are associated with Trimethoprim?

A

-Jaundice
-Allergy

69
Q

What are examples of antiviral drugs?

A
  1. Acyclovir
  2. Ganciclovir
  3. Ribavirin
  4. Lamivudine
  5. Azidothymidine
70
Q

How do antivirals kill cells?

A
  1. Antiviral drug resembles a nucleoside
  2. Virally infected cell converts the antiviral into a false nucleotide
  3. DNA synthesis by DNA polymerase is blocked
71
Q

What is a nucleoside?

A

Sugar + Base. NO phosphate

72
Q

What base does Acyclovir resemble?

A

Guanine (G)

73
Q

What does Acyclovir treat?

74
Q

What base does Ganciclovir resemble?

A

Guanine (G)

75
Q

What does Ganciclovir treat?

A

Herpes-5 aka CMV (retinal HIV)

76
Q

What base does Ribavirin resemble?

A

Guanine (G)

77
Q

What does Ribavirin treat?

78
Q

What base does Lamivudine resemble?

A

Thymine (T)

79
Q

What does Lamivudine treat?

A

Hepatitis B, HIV

80
Q

What base does Azidothymidine resemble?

A

Thymine (T)

81
Q

What does Azidothymidine treat?

Microbiology- HLSC 124 🦠 (18 decks)

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