Antibiotics: Cell Wall Synthesis inhibitors Flashcards

1
Q

what are the cell wall synthesis inhibitor drugs?

A
  1. Beta lactam antibiotics
  • Penicillins *
  • Cephalosporins*
  • Carbapenems
  • Monobactam
  1. Vancomycin*
  2. Bacitracin
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2
Q

ß-lactams will work on what bacteria?

A

actively synthesizing peptidoglycan or in the log phase

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3
Q

how do ß-lactams work?

A

bind and inactivate bacterial enzymes essential for cross-linking between peptidoglycan chains

(inactivates transpeptidases and carboxypeptidases)

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4
Q

inactivation of enzymes for bacterial cross linking by ß-lactams will cause activation of what?

A

it will activate Autolysins that degrade cell wall and eventually kill the bacteria

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5
Q

ß-lactams drugs are considered what type of drugs?

A

bacteriocidal drugs

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6
Q

what are 3 ways that bacteria have adapted to evade ß-lactams?

A
  1. Hydrolysis of antibiotic by Beta-lactamases
    • (cleave beta-lactam ring and destroy the antibitotic)
  2. Alteration of PBPs (penicillin-binding proteins)
    • bacteria can alter their PBPs so that beta-lactams cannot bind them
  3. Reduced permeability of Gram negative outer membrane
    • bacteria alter their porins and size of porin channels
    • Prevent the large molecules of the beta-lactam drug from penetrating the cell wall
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7
Q

what are the enzymes that inactivate ß-lactams antibiotics?

A

1) Penicillinases – specific for penicillins
2) Cephalosporinases – target cephalosporins
3) Carbapenemases – inactivate carbepenems
4) Extended-Spectrum B-lactamases (ESBLs) - inactivate cephalosporins and penicillins

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8
Q

what is important about the penicillin structure?

A

it contains a ß-lactam ring

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9
Q

what is penicillin’s mode of action?

A

Inhibition of transpeptidases (PBPs) with subsequent Inhibition of cell wall synthesis & bacterial cell death

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10
Q

what side effects can penicillin have?

A

hypersensitivity

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11
Q

name the different types of penicillin.

A

1) Penicillin G, Penicillin V
2) Aminopenicillins
3) Extended spectrum Penicillins (Anti-pseudomonal
4) Penicillinase-Resistant Penicillins
5) Beta-lactamase Inhibitors
6) Penicillin + Beta-lactamase inhibitor

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12
Q

what penicillins are susceptible to penicillinase (ß-lactamase)?

A

penicillin G and V

Aminopenicillins

Extended spectrum Penicillins (Ureidopenicillins)

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13
Q

what are the penicillins that are penicillinase resistant?

A

Methicillin

Nafcillin

Oxacillin

Cloxacillin

Dicloxacillin

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14
Q

how is penicillin G administered?

A

through IV

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15
Q

how is penicillin V administered?

A

orally

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16
Q

how is penicillin G and V’s spectrum?

A

narrow

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17
Q

penicillin G and V are used for what type of bacteria?

A

gram positive bacteria

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18
Q

Methicillin, Nafcillin, Oxacillin, Cloxacillin, Dicloxacillin are used only for what bacteria?

A

staph infections

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19
Q

aminopenicillins like ampicillin and amoxicillin have this side effect…

A

diarrhea

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20
Q

name the aminopenicillins?

A

ampicillin and amoxicillin

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21
Q

how are Aminopenicillins: Ampicillin, amoxicillin, taken?

A

orally

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22
Q

what is another term for penicillinase?

A

ß-lactamase

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23
Q

Aminopenicillins: Ampicillin, amoxicillin, are used for what infection?

A

enterococci and listeria infections

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24
Q

what is an important anti-psudomonal penicillin?

A

pipercacillin

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25
Q

What are the penicillinase resistant penicillins?

A

Methicillin,

Nafcillin

Oxacillin

Cloxacillin

Dicloxacillin

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26
Q

how are cloxacillin and dicloxacillin administered?

A

orally

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27
Q

how are Methicillin, Nafcillin, Oxacillin administered?

A

Intavenous

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28
Q

what bacteria have developed resistance to methicillin?

A

MRSA, MRSE

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29
Q

methicillin resistance refers to resistance against what drugs?

A

met, naf, oxa, clox, diclox

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30
Q

what is the drug of choice for staph infection?

A

Methicillin, Nafcillin, Oxacillin, Cloxacillin, Dicloxacillin

(Naf for Staph)

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31
Q

what is the drug of choice to treat MRSA or methycillin resistance?

A

vancomycin

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32
Q

what is an example of a common staph infection?

A

abcesses

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33
Q

what is the drug of choice for listeria infections?

A

Aminopenicillins

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34
Q

what do ß-lactamase inhibitors do?

A

Inactivate some types of beta-lactamase enzymes produced by bacteria

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35
Q

Give an example of a ß-lactamase inhibitors

A

Clavulanic acid (clavulanate)

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36
Q

are they effective working alone? what do you do to correct this?

A

no, always used in combination penicillin

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37
Q

how effective are beta lactamase inhibitors when administered alone?

A

inactive at inhibiting bacteria on their own

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38
Q

how do you increase the effectivity of ß-lactamase inhibitors?

A

administer in conjunction with penicillin

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39
Q

do beta lactamase inhibitors all work will all beta lactamases

A

no

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40
Q

what is a Beta lactam + beta lactamase inhibitor combination?

A

penicillins that have been combined with beta lactamase inhibitors to increase effectiveness

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41
Q

what are the Beta lactam + beta lactamase inhibitors?

A

Amoxicillin + clavulanate (Augmentin)

Piperacillin + tazobactum

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42
Q

how is the antibiotic spectrum of Beta lactam + beta lactamase inhibitors?

A

broad

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43
Q

beta lactam + beta lactamase inhibitor has improved activity against?

A

Improved activity against beta-lactamase producing staphylococci and selected gram negative rods*

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44
Q

what is another name for cephalosporins?

A

ß lactam antibiotics

45
Q

what type of antibiotic are cephalosporins?

A

bacteriocidal

46
Q

why do bacteria develop reistance to cephalosporins?

A

Production of beta-lactamases and cephalosporinases

47
Q

what are cephalosporins less susceptible to?

A

penicillinases

48
Q

do cephalosporins target only a limited amount or a wide amount of bacteria?

A

cephalosporins target a wide antibacterial spectrum

49
Q

cephalosporins are more resistant to what?

A

to many ß-lactamases

50
Q

how are the cephalosporins classified?

A

1st, 2nd, 3rd, 4th generation

51
Q

1st generation cephalosporins will attach what bacteria?

A

gram positive and some gram negative

52
Q

what gram negative bacteria are targeted by using 1st gen. cephalosporins?

A

proteus

e. coli

klebsiella pneumonie

cephalexin

cefuzzlin

53
Q

what are some of the 2nd gen. cephalosporins?

A

cefotoxin

cefuroxime

54
Q

what is an example of a bacteria targeted by cefuroxime, cefuclor, cefuman?

A

H. Inlfuenza

E.Coli

55
Q

2nd generation cephalosporins will target what bacteria?

A

gram negative and some anaerobes

56
Q

give an example of an anaerobic bacteria targetted by 2nd gen cephalosporins?

A

bacteroides fragilis

57
Q

what can inhibit 2nd generation cephalosporins?

A

beta-lactamases

58
Q

what will 3rd gen. cephalosporins target?

A

gram positive bacteria mostly

some gram negative bacteria

59
Q

what are some of the 3rd gen. cephalosporins?

A

Cefotaxime, Ceftriaxone, Ceftazidime

60
Q

what is special about the 3rd gen cephalosporins?

A

they can cross the Blood-Brain Barrier

61
Q

what gram negative bacteria can 3rd generation cephalosporins target?

A

pseudomonas

62
Q

when are 3rd generation cephalosporins used?

A
  1. Empiric therapy for Bacterial meningitis***
  2. Gonorrhoeae
  3. Pseudomonas infections
63
Q

how susceptible are 3rd generation cephalosporins to beta-lactamases?

A

they are Very resistant to some beta-lactamases*

64
Q

what cephalosporin do you give for adults with meningitis?

A

Ceftriaxone

65
Q

what cephalosporin do you give for children with meningitis?

A

Cefotaxime

66
Q

what is the drug of choice for Pseudomonas infection?

A

ceftazidime

67
Q

what is the drug of choice for gonorrhoeae?

A

ceftriaxone

68
Q

what is an example of a 4th gen cephalosporine?

A

Cefepime

69
Q

4th gen cephalosporins are resistant to what?

A

ß-lactamases

70
Q

4th gen cephalosporins will be excellent against what bacteria?

A

pseudomonas

71
Q

what gram neg. bacteria will 4th gen cephalosporins attack very effectively?

A

psudomonas aureginosa

72
Q

what infection are 4th generation cephalosporins used for?

A

treatment of nosocomial infections by suspected beta-lactamase-producing bacteria*

73
Q

what is the 5th generation cephalosporins?

A

Ceftaroline

74
Q

how is the antibiotic spectrum of 5th gen. cephalosporins?

A

broad

75
Q

against what infection is 5th generation cephalosporins used against?

A

MRSA and MRSE

76
Q

what is the drug of choice for methycilin resistant staph infections?

A

vancomycin

77
Q

what are the side effects of cephalosporins?

A

hypersensitivity

Cross-sensitivity between penicillins & cephalosporins

78
Q

what organisms not covered by cephalosporins?

A

Listeria monocytogenes****

Atypical bacteria (Chlamydia, Mycoplasma)

MRSA (exception; ceftaroline coveres MRSA)

Enterococci

79
Q

what are cabapenems?

A

ß lactams

80
Q

what is an example of a carbapenems?

A

imipenem

81
Q

carbapenems are always used with what other drug?

A

cislastatin (a dihydropeptidase inhibitor)

82
Q

carbapenems are what type of drugs?

A

reserve drugs

83
Q

carbapenems are used against what?

A

anaerobic and gram neg. rods

84
Q

what is an example of monobactam?

A

aztreonam

85
Q

monobactams are resistant to what?

A

ß lactamases

86
Q

how is the spectrum of monobactam drugs?

A

narrow spectrum

87
Q

Monobactam drugs used for what?

A
  • Can be given to patients allergic to penicillin*
  • treatment of hospital-acquired multi-drug resistant Gram-negative bacteria
88
Q

can this type of drugs be given to people with allergies to penicillin?

A

yes

89
Q

monobactam is used on what type of bacteria (+ or -)?

A

gram neg aerobic only

90
Q

what is vancomyicin?

A

a bacteriocidal glycoprotein

91
Q

how does vancomyicin work?

A

binds to (D-Ala)-(D-Ala) of peptidoglycan chain and inhibits the cross linking

92
Q

how is the spectrum for vancomyicin?

A

narrow

93
Q

when will you administer vancomyicin?

A

for serious infection caused by drug resistant gram positive organisms

94
Q

give an example of an organism which can be treated with this antibacterial (vancomyisin)

A

MRSA

penicillin resistant pneumococci

penicillin resistant clostridium difficile

95
Q

how can bacteria increase resistance to vancomyicin?

A

changing its peptidoglycan chains:

D-Ala-D-Ala to D-Ala-D-Lac

there will be decreased affinity to vancomyicin in binding site

96
Q

These bacteria are resistant to vancomyicin…

A

enterococci and staphylococci (VRE and VRSA)

97
Q

what are some adverse reactions that can occur by using vancomyicin?

A

nephrotoxicity, orotoxicity, thrombophebitis

red man syndrome (due to continuous release of histamine)

(prevented through pre-treatment with antihistamines)

98
Q

what 2 other drugs work as cell wall synthesis inhibitors?

A

bacitracin = very nephrotoxic

cycloserine = gram pos and neg bacteria

99
Q

cycloserine is used exclusively to treat what bacteria?

A

tuberculosis

100
Q

vancomycin is administered orally or intravenously for treatment of pseudomembranous colitis?

A

Oral

101
Q

what drugs do you use to treat VRE and VRSA?

A
  • Quinupristin-dalfopristin***
  • Linelozid
102
Q

what does bacitracin do?

A

inhibit cell wall synthesis

103
Q

why is bacitracin not used so frequently?

A

it is nephrotoxic

104
Q

how do you administer bacitracin?

A

topically only

105
Q

for what infections do you use bacitracin?

A

Staphylococcal & Streptococcal skin infections *

106
Q

what do Anti-Mycobacterial agents do?

A

inhibit synthesis of mycolic acid

107
Q

where do you find mycolic acid?

A

mycobacterial cell wall

108
Q

what are examples of anti-mycobacterial agents?

A

Isoniazid

Ethambutol

Ethionamide

Cycloserine