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D&D Infectious Disease Midterm > Pharm - Penicillins & cell wall synth gen concepts > Flashcards

Pharm - Penicillins & cell wall synth gen concepts Flashcards

1
Q

name 3 glycopeptide antibiotics

are they beta lactams?

A

not beta lactams

vancomycin
telavancin
dalbavancin

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2
Q

name 4 “miscellaneous” AB’s

A

daptomycin
fosfomycin
bacitracin
polymyxin

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3
Q

name 3 “classes” of penicillins

A

G and V

B-lactamase resistant penicillins

extended spectrum penicillins

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4
Q

name 3 “extended spectrum” penicillins

A

amino, carboxy, ureido

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5
Q

name 5 beta lactam classes

A

penicillins
cephalosporins
monobactams
carbapenems
B-lactamase inhibitors

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6
Q

differentiate between gram positive and gram negative cell walls as far as peptidoglycan

A

gram positive has MANY more layers of peptidoglycan than gram negative

in gram negative, peptidoglycan layer is very thin

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7
Q

in gram positive cell walls, what binds the many layers of peptidoglycan together?

A

lipoteichoic acid

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8
Q

where is the penicillin binding protein located in bacteria?
is it in gram positive, gram negaitve, both?

A

on the cell membrane

in both gram pos and neg

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9
Q

which has porin channels and what do these do?
(gram pos or neg)

A

gram neg

controls entry into the bacteria

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10
Q

which can antibiotics enter more easily and why - gram positive or gram negative bacteria?

A

gram positive is easier to enter

it’s more porous

gram negative has a DOUBLE phospholipid membrane (outer and inner)

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11
Q

which has LPS - gram positive or negative

A

gram negative

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12
Q

compare the location of beta lactamases between gram pos vs gram neg

A

gram pos - outside the peptidoglycan layers

gram neg - most in the periplasmic space (btwn the 2 membranes) and some also in periplasmic space but trapped within the lipoproteins. –NOT outside the bacteria like in gram positive

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13
Q

peptidoglycan is composed of….

A

sugar + amino acids (peptides)

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14
Q

what enzyme do beta lactams like penicillins and cephalosporins block

A

transpeptidase - AKA PBP (penicillin binding protein)

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15
Q

explain what transpeptidase does
explain specific for staph aureus

A

enzyme involved in synthesizing cell wall peptidoglycan

forms a peptide cross bridge between 2 glycopeptide polymers via amino acid side chains. Specifically, in staph aureus, the bridge is (Gly)5-D-Ala between lysines. removes the last (5th) alanine and fuses the 4th onto the glycine of the other glycopeptide monomer

this reaction happens millions of times to form the cell wall

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16
Q

what is NAM

A

N-acetylmuramic acid

single sugar monomer (glycopeptide) that, along with NAG (N-acetyl glucosamine) forms the backbone for peptidoglycan

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17
Q

NAG + NAM are attached to….

A

a penta peptide (5 amino acids)

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18
Q

what are the terminal 2 amino acids in the glycopeptide polymer

A

D-ala D-ala

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19
Q

for cell wall synthesis to occur, it’s very important for PBP to bind…..

A

D-ala D-ala

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20
Q

explain the 3 “stages” of peptidoglycan/cell wall synthesis

A
  1. Make everything within the bacteria. racemierize and condense L-Ala to D-Ala with D-alanyl-D-alanine synthase
  2. Tranport outside of the membrane to start forming crossbridge
  3. Transglycosylation (fuse sugars) and transpeptidation (fuse amino acids) by PBP
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21
Q

what does D-alanyl-D-alanine synthase do and what inhibits it

A

racemerizes and condenses L-Ala into D-ala

inhibited by D-cycloserine (a medication)

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22
Q

Name 2 rings within penicillin

name 2 enzymes and their sites that can break down penicillin - RESISTANCE

A

4-membered beta lactam ring is fused to a thiazoline ring

beta lactam ring broken down by penicillinase/b lactamase

amidase is an enzyme that can destroy amide bond (O=C-N)
CN bond broken

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23
Q

penicillins and other beta lactams structurally resemble what?

A

D-alanyl D-alanine

(D-ala D-ala)

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24
Q

explain the MOA of penicillin

A

IRREVERSIBLY binds and inhibits PBP (transpeptidase enzyme) which forms a highly unstable penicilloyl-enzyme intermediate

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25
Q

true or false

penicillin reversibly binds PBP

A

FALSE

irreversibly with covalent bond

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26
Q

what does penicillin compete with

A

D-ala D-ala for PBP

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27
Q

true or false

all the beta lactams have the same MOA as penicillin

A

true

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28
Q

What penicillins CANNOT be hydrolyzed by staph beta lactamases?

are they active against MRSA?

A

antistaphylococcal penicillins like methicillin, nafcillin, oxacillin, and cloxacillin

NOT active against MRSA still

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29
Q

Penicillin V vs Penicillin G

A

Penicillin V given orally

Penicillin G given IV

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30
Q

name 2 things that penicillins (ie: pen g) are NOT active against

A

gram negative rods and staph aureus (resistance!! - b lactamases)

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31
Q

name what regular penicillins (like pen g) are active against

A

gram positives and gram negative cocci

NON-b-lactamase producing anaerobes

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32
Q

name 3 things that antistaphylococcal penicllins are active against

A

staphylococci (NOT MRSA)
streptococci
s. epidermis

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33
Q

true or false

penicillin G is active against staph

A

FALSE - staph is resistant through B-lactamases

only the antistaphylococcal penicillins are active against staph - BUT STILL NOT MRSA

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34
Q

name some things that antistaphylococcal penicillins are NOT active against

A

MRSA
enterococci
anaerobic
gram negatives

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35
Q

what are extended spectrum penicillins

A

like penicillin, but better against gram negatives - wider spectrum

36
Q

true or false

extended spectrum penicillins are NOT active against staph

A

true

get hydrolyzed by beta lactamases

37
Q

name 2 extended spectrum penicillins

A

aminopenicillins
antipseudomonal penicillins

38
Q

4 mechanisms of penicillin resistance

what are the 2 main?

A

2 main:
-inactivation by B lactamases
-modification of target PBP’s

other 2:
-impaired penetration of the drug to target BPB (only gram - through porin channels)
-antibiotic efflux

39
Q

name 2 ways that PBP is modified to give resistance

A

major - staph aureus modifies to PBP2a so penicillin can’t bind

other - pneumococcal and enterococci do same

40
Q

**penicillinase acts on….

A

B lactam ring - breaks it

41
Q

the penicillins differ in their ___ and ____

A

acid stability and protein binding

42
Q

which 4 penicillins are acid-stable? what does this say about their route of administration?

A

Penicillin V
dicloxacillin
ampicillin
amoxicillin

given orally and relatively well absorbed

43
Q

oral penicillins should be administered how in regard to food?

A

1-2 hours before or after a meal

44
Q

which penicillin is usually given IV

A

Pen G
could also be given IM but it’s irritating and painful

45
Q

true or false

penicillins are highly plasma protein (albumin) bound

A

TRUE
can displace other things

46
Q

explain the distribution of penicillins

A

not well distributed to eyes and prostate and CNS

47
Q

how is penicillin mainly excreted and why is this important

A

UNCHANGED (not lot of metabolism) in the kidneys

therefore, renal function is important consideration

48
Q

route nafcillin and class

A

IV

anti-staphylococcal

49
Q

route oxacillin and class

A

IV

anti-staphylococcal

50
Q

route and class cloxacillin

A

PO

anti-staphylococcal

51
Q

route and class dicloxacin

A

PO

anti-staphylococcal

52
Q

route penV

A

oral

53
Q

route and class amoxicillin

A

PO

extended-spectrum penicillin

(same as augmentin)

54
Q

route and class pipercillin

A

IV

extended spectrum penicillin

55
Q

route and class ticarcillin

A

IV

extended spectrum penicillin

56
Q

as mentioned, penicillins are weakly distributed to the CNS. Therefore, can they be used for meningitis

A

they actually can - bc in meningitis the meninges are kind of “leaky” so they can still get in

57
Q

name 2 IM penicillin injections and rationalize the ingredients

A

benzathine penicillin - benzathine is a stabilizer for IM injection

procaine penicillin G - procaine is anesthetic for IM injection to help with the pain

DEPOT

58
Q

benzathine penicillin and procaine penicillin G is effective treatment for….

A

B-hemolytic streptococcal pharyngitis
(STREP THROAT)

59
Q

penicillin is synergistic with which 2 drugs

A

gentamicin and tobramycin

60
Q

_______ is really only indicated for minor infections (like simple respiratory inf or minor SSTI) because of relatively poor bioavailability

A

penicillin V

61
Q

name 3 anti-staphylococcal penicillins

which strain are they specifically used to treat

A

nafcillin
cloxacillin
dicloxicillin

ONLY MSSA
penicillinase-producing staphylococci - they are resistant to the B lactamase they produce and can survive

62
Q

as mentioned, nafcillin, cloxacillin, and dicloxacillin can be used to treat MSSA and penicillinase producing staphylococci

name their routes of administration as a recap

A

nafcillin - IV

cloxacillin and dicloxacillin - PO

63
Q

name the aminopenicillins and their general common feature

which is better absorbed?

how do their spectrums of activity differ?

A

ampicillin and amoxicillin

they are stable orally!!!!

amox is better orally absorbed

both have similar spectrum

64
Q

explain what kind of infections amox/ampicillin can and CANT be used for

A

can - UTI, lowerrespiratory tract, sinusitis, otitis, meningitis, speticemia

NOT - for common nosocomial infections like pseudomonas, enterobacter, and klebsiella

65
Q

what is calvulanic acid

A

beta lactamase inhibitor often combined with amoxicillin

66
Q

chemical name for the “extended spectrum” penicillins

A

carboxypenicillins AND ureidopenicillins

67
Q

example of ureidopenicillin and route administration

A

pipercillin
IM/IV

68
Q

what can pipercillin be combined with

A

a beta lactamase inhibitor to increase activity

ie- TAZOBACTAM, sulbactam, clavulanic acid

69
Q

explain what pipercillin is active against

A

lot of gram negatives

MAINLY - PSEUDOMONAS (NOSOCOMIAL) and klebesiella

70
Q

anti-pseudomonial penicillins

A

extended spectrum

carboxy penicillins - like ticarcillin

ureido penicillins - like pipercillin

71
Q

name a carboxypencillin as well as route administration

A

ticercillin IV/IM

72
Q

ticarcillin is given in combo with…..

A

clavulanate

73
Q

briefly explain what ticarcillin can be used for

A

more serious infections - like bacteremia, pseudomonas, bone and joint infections, SSTI, UTI, gynecologic infections, intra-abdominal infections, lower resp

74
Q

carboxypenicillins are NOT used for ___ and ___

A

gram positive cocci and listeria

75
Q

can ampicillin be combined with a beta lactamase inhibitor

A

YES

76
Q

side effects penicillin

A

well tolerated generally

obviously - risk of hypersensitivity and anaphylaxis (less than 1%) which could progress to shock

SEIZURES in renal failure pts – only for high doses – we must lower the dose for them!!!

77
Q

HOW does penicillin cause hypersensitivity in some patients

A

the degradation products of penicillin like penicilloic acid and products of alkaline hydrolysis bind the host protein

78
Q

which penicillin can cause neutropenia

A

nafcillin

79
Q

which penicillin can cause interstitial nephritis

A

methicillin

80
Q

which penicillin can cause hepatitis

A

oxacillin

81
Q

NVD from penicillins is most common when

A

either broad spectrum or high doses – killing all the good

82
Q

_____- can cause pseudomembranous colitis and vaginal candidiasis

A

ampicillin

83
Q

3 DDIS of PEN G and PEN V

A

decrease effectiveness oral contraceptives

probenecid increases plasma levels

colestipol decreases PEN V (oral) absorption

84
Q

are penicillins bactericidal or static

A

CIDAL

85
Q
A

D&D Infectious Disease Midterm (26 decks)

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