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Flashcards in inhibitors of cell wall synthesis Deck (53):
1

structure conferring cell wall rigidity and resistance to osmotic lysis in both G+ and G- bacteria

peptidoglycan

2

difference between G+ and G-

  • G+: peptidoglycan is the only layered structure external to the cell membrane and it is thick
  • G-: outer membrane external to a very thin peptidoglycan

3

peptidoglycan is composed of a backbone of what two alternating sugars 

  • N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)

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4

a chain of four amino acids is linked to what sugar in the peptidoglycan 

N-acetylmuramic acid (NAM)

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5

a peptide bridge cross links the tetrapeptide chains in the peptidoglycan. Which two amino acids are connected 

D-gln and D-ala

6

inhibition of any stage of the synthesis, export, or assembly of peptidoglycan leads to what 

bacterial cell death

7

how are abx that inhibit cell wall synthesis bactericidal 

  • cell death due to osmotic lysis
  1. ​loss of cell wall integrity is due to bacteria's autolysins which cleave peptidoglycan bonds in normal course of cell growth
  2. with abx, autolysis proceeds without normal cell wall repair

8

name the 4 B-lactams abx 

  1. penicillins
  2. cephalosporins
  3. monobactams
  4. carbapenems 

9

name the 4 natural penicillins. which is the prototype? 

  1. penicillin G
  2. Benzathine penicillin 
  3. Probaine Penicillin
  4. Penicillin V

10

name the 3 penicillins that are penicillinase resistant. which is the prototype? 

  • Nafcillin
  • Dicloxacillin
  • Oxacillin

11

name the penicillins that have extended spectrum. which is the prototype? 

  • Ampicillin
  • Amoxicillin

12

name the penicillins that are antipseudomonal. which is the prototype? 

  • piperacillin
  • ticarcillin 

13

what is the mechanism of action of penicillins

prevent transpeptidation (cross links pentapeptides of peptidoglycan)

  • prevent the action of penicillin binding protein  

14

what group of abx has the highest antibacterial activity against certain G+ bacteria 

natural penicillins 

15

coverage of natural penicillins 

  • Highest coverage against certain G+ 
  • some G- coverage 

16

natural pencillin don't cover what organisms 

  • inactivated by B-lactamase (penicillinase): not effective against strains of S. aureus 
  • No antipseudomonal activity 

17

route of Penicillin G 

  • IV
  • IM

18

route of Benzathine penicillin 

IM

19

route of Procaine penicillin G 

IM

20

route of Penicillin V 

oral 

21

coverage of Penicillinase-Resistant Penicillins 

  • lower activity against G+
  • some G- 

22

what is the DOC for penicillinase producing S. aureus (MSSA) 

Penicillinase-resistant penicillins

23

what group is Nafcillin in 

Penicillinase-resistant penicillins

24

route of administration of Nafcillin 

  • parenteral 

25

what group is Dicloxacillin (Cloxapen) in 

Penicillinase-resistant penicillins

26

route of administration of Dicloxacillin 

oral 

27

what group is Oxacillin in 

Penicillinase-resistant penicillins

28

route of administration of Oxacillin 

oral 

29

mechanism of resistance of MRSA 

  • produces an alternate PBP which decreases affinity of the B-lactam Abx to PBP

30

what is the only B-lactam that can be used to treat MRSA 

Ceftaroline 

31

extended spectrum penicillins have what coverage

  • lower G+ coverage
  • extended G- coverage 

32

extended spectrum penicillins are ineffective against what organism 

no antipseudomonal activity 

33

DOC for Lysteria infections 

extended spectrum penicillins

34

what group is ampicillin in 

extended spectrum penicillins

35

route of administration of extended spectrum penicillins 

oral

36

what group is amoxicillin in 

extended spectrum penicillins

37

what is the ampicillin rash 

  • occurs in 5-10% of children receiving extended spectrum penicillins
  • dull, red, maculopapular rash
  • onset: 3-14 after start of Abx

**rash is not allergic 

38

high percentage of patients with what infection will develop a ampicillin rash during therapy with ampicillin 

infectious mononucleosis (EBV) 

39

coverage of antipseudomonal penicillins 

  • extended spectrum penicillins plus some enteric G- 

40

major use of antipseudomonal penicillins

  • pseudomonas aeruginosa
  • acinetobacter 

41

can antipseudomonal penicillins be used as a seperate abx 

NO

  • used in combination with aminoglycosides to prevent resistance 

42

what group is Pipercillin in 

antipseudomonal penicillins

43

what group is Ticarcillin in 

antipseudomonal penicillins

44

What are Clavulanic acid, Sulbactam, and Tazobactam 

B-lactamase inhibitors 

45

function of B-lactamase inhibitors 

  • added to ampicillin, amoxicillin, ticarcillin, piperacillin to extend the spectrum to include organisms that are resistant to B-lactamase (penicillinase) 

46

are the penicillins used in combo with B-lactamase inhibitors active against MRSA?

no

47

Route of administration of ampicillin; sulbactam (Unasyn) 

parenteral 

48

route of administration of amoxicillin; clavulanic acid (augmentin) 

oral

49

Route of administration of piperacillin; tazobactam (Zosyn) 

IV

50

route of administration of Ticarcillin; Clavulanic acid (timentin) 

IV

51

different functions of bacterial B-lactamase (penicillinase) 

  1. alteration of PBP
  2. decreased permeability of bacteria cell to PCN
  3. autolytic enzymes not being activated -> forming tolerant organisms (bacteria become dormant) 
  4. lack of cell wall 

52

toxicity of penicillins 

allergy 

53

abx choice for early infection of borrelia burgdorferi

amoxicillin or doxycycline