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KG - Pharmacology > Penicillin > Flashcards

Penicillin Flashcards

1
Q

what structure confers cell wall rigidity and resistance to osmotic lysis in both G+ and G- bacteria?

A

peptidoglycans - large sacculus that surrounds bacterium

  • In G+, peptidoglycan is only structure external to cell membrane
  • In G-, there is an outer membrane external to thin peptidoglycan layer
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2
Q

what are peptidoglycans composed of?

A
  • backbones of two alternating sugars
  • chain of 4 amino acids
  • peptide bridge that cross links the tetra peptide chains
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3
Q

“inhibition of any stage of synthesis/export/assembly of peptidoglycan leads to inhibition of bacterial cell growth and, in most cases, _____________”

A

“inhibition of any stage of synthesis/export/assembly of peptidoglycan leads to inhibition of bacterial cell growth and, in most cases, CELL DEATH”

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4
Q

how are peptidoglycans formed?

A
  1. addition of subunits, assembled in cytoplasm
  2. transport through cytoplasmic membrane to cell surface
  3. subsequent cross-linking by cleavage of terminal stem-peptide amino acid
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5
Q

when can antibiotics interfere with cell wall synthesis of the peptidoglycans?

A
  1. transglycosylation (joining NAM-NAG)
  2. transpeptidation (cross links pentapeptides)
  3. NAG reduction to NAM
  4. transport across the inner membrane
  5. amino acid mimicry (pentapeptide chain)

***for #1, #2 - enzymatic action performed by PENICILLIN BINDING PROTEINS (PBPs)

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6
Q

what does fosfomycin do?

A

inhibits one of the first steps in synthesis of peptidoglycan

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7
Q

what does cycloserine do?

A

structural analog of amino acid D-alanine, needed in synthesis of peptidoglycan

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8
Q

what does bacitracin do?

A

inhibits conversion to its active form of lipid carrier that moves water soluble cytoplasmic peptidoglycan subunits through cell membrane to cell exterior

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9
Q

what do glycopeptides (vancomycin) do?

A

sterically inhibit addition of subunits to peptidoglycan backbone

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10
Q

what do beta-lactam antibiotics (penicillins, cephalosporins, carbapenems, monobactams) do?

A

prevent cross linking reaction called transpeptidation

  • performed by transpeptidases or PBPs
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11
Q

are antibiotics that inhibit bacterial cell wall synthesis bacteriostatic or bactericidal?

A

virtually all = bactericidal

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12
Q

w/ antibiotics that inhibit cell wall synthesis, why do cells die?

A

osmotic lysis

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13
Q

why do cells have loss of cell wall integrity following treatment?

A

autolysins

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14
Q

w/ agents that inhibit cell wall growth, ________ proceeds without normal cell wall repair.

A

w/ agents that inhibit cell wall growth, AUTOLYSIS proceeds without normal cell wall repair.

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15
Q

protein synthesis inhibitors _________ the action of the cell wall synthesis inhibitors

A

protein synthesis inhibitors PREVENT the action of the cell wall synthesis inhibitors

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16
Q

what are properties of ICWS?

A

properties of ICWS:

  • activity against G+
  • spectrum (G-, anaerobic, etc coverage)
  • activity against Pseudomonas aeruginosa
  • acid resistance - oral absorption
  • CNS penetration
  • route of elimination
  • uniwue adverse effects
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17
Q

list: Beta lactams

A
  • penicillins
  • cephalosporins
  • monobactams
  • carbapenems
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18
Q

list: other inhibitors of CWS (not beta lactams)

A
  • vancomycin
  • fosfomycin
  • bacitracin
  • cycloserine
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19
Q

list: penicillins –> natural penicillins

A
  • PENICILLIN G (prototype)
  • benzathine penicillin
  • procaine penicillin G
  • penicillin V
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20
Q

list: penicillins –> penicillinase

A
  • NAFCILLIN (prototype)
  • docloxacillin
  • oxacillin
  • *Methicillin
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21
Q

list: penicillins –> extended spectrum

A
  • AMPILLIN (prototype)
  • amoxicillin
  • bacamicillin
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22
Q

list: penicillins –> antipseudomonal

A
  • PIPERACILLIN (prototype)
  • ticarcillin
  • mezlocillin
  • carbeicillin
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23
Q

info about NATURAL PENICILLINS

A
  • HIGHEST antibacterial activity against certain G+ bacteria, incl. G+ anaerobic bacteria
  • some G- coverage
  • readily activated by BETA LACTAMASE (penicillinase), not effective against strains S. aureus
  • NO ANTIPSEUDOMONAL activity
  • eliminated by kidney
  • poor CNS penetration
  • Pencillin V acid resistant
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24
Q

how can the natural pencillins be administered?

A

PEN G = IV, IM
benathine penicillin = IM depot
procaine penicillin = IM
pen V = oral

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25
Q

info about PENICILLINASE resistant penicillins

A
  • lower activity again certain B+ bacteria
  • resistant to some penicillinase producing bacteria
  • some G- coverage
    some acid stable & highly protein bound
  • DOC for MSSA
  • more than 20% of S. aureus resistant (MRSA)
  • hepatic metabolism, renal excretion
26
Q

how can PENICILLINASE be administered?

A

NAFCILLIN = Unipen, IM/IV
Dicloxacillin - oral
oxacillin - oral

*** Metacillin = testing only!

27
Q

MRSA mechanism of resistance?

A
  • NOT via production of beta lactamase
  • produces alternate PBP, decreases affinity of beta lactam antibiotics to PBPs
  • NO BETA LACTAM can be used to treat MRSA (EXCEPT CEFTAROLINE)
28
Q

info about EXTENDED SPECTRUM penicillins

A
  • lower G+ coverage
  • extended G- coverage (E coli, salmonella, sigella, H infuenza, proteus) –mostly in GI tract
  • NO ANTIPSEUDOMONAL activity
  • resistance develops frequently
  • susceptible to beta lactamase
  • acid resistance
  • urinary excretion
  • DOC FOR LISTERIA
29
Q

how can EXTENDED SPECTRUM penicillins be administered?

A
  • AMPICILLIN = oral

- amoxicillin = oral

30
Q

which rash is NOT a hypersensitivity rash?

A

ampicillin, usu corresponds w/ hx of EBV

31
Q

info about ANTIPSEUDOMONAL penicillins

A
  • spectrum = bacteria covered by extended spectrum penicillins + some additional enteric G- bacilli
  • major use = pseudomonas aeruginosa, acinetobacter
  • susceptible to beta lactamase
  • acid sensitive
  • renal excretion
32
Q

which group of penicillins should you NEVER use alone?

A

antipseudomonal penicillins

33
Q

how can ANTIPSEUDOMONAL penicillins be administered?

A

um.. not sure - wasn’t on slides.. but here is the list!

  • PIPERACILLIN
  • ticarcillin
  • mezlocillin
  • carbenicillin
34
Q

why add beta lactamase inhibitors to ampicillin, ticarcillin, amoxicillin, and piperacillin?

A

extends spectrum of agents to include many organisms that are resistant by virtue of beta lactamase production

  • not all B-lactamase inhibited
  • can become resistant (ie: MRSA)
35
Q

Unasyn = _______ + _______

A

Unasyn = ampicillin + sulbactam

  • IV, IM
36
Q

augmentin = _______ + _______

A

augmentin = amoxicillin + clavulanic acid

  • oral
37
Q

zosyn = _______ + _______

A

zosyn = piperacillin + tazobactam

  • IV
38
Q

timentin = _______ + _______

A

timentin = ticarcillin + clavulanic acid

39
Q

what are reasons of bacterial resistance to penicillins?

A
  1. inactivation of penicillin by BACTERIAL BETA-LACTAMASE (penicillinase) (enzyme is inducible)
  2. DECREASED PERMEABILITY of bacterial cell to penicillins (G-)
  3. ALTERATIONS IN PBPs, which prevent penicillin form binding (MRSA)
  4. autolytic enzymes NOT BEING ACTIVATED, forming tolerant organisms
  5. LACK OF CELL WALL
40
Q

what are examples of allergies resulting from penicillins?

A
  • allergy, all forms (not ampicillin rash)
  • electrolyte imbalance
  • GI probs
  • superinfections
41
Q

pharmacokinetics of penicillins

A
  • good tissue penetration
  • poor CNS penetration
  • mostly renal elimination
  • filtration/tubular excretion
  • probenecid inhibits renal elimination
42
Q

Bacteria = ENTEROBACTER, CITROBACTER, SERRATIA (G- rods)

Treat with _____?

A
  • TMP-SMZ
  • quinolone
  • carbapenem
43
Q

Bacteria = SHIGELLA (G- rods)

Treat with _____?

A

quinolone

44
Q

Bacteria = SALMONELLA (G- rods)

Treat with _____?

A
  • TMP-SMZ
  • quinolone
  • cephalosporine (3rd gen)
45
Q

Bacteria = BRUCELLA SPECIES (G- rods)

Treat with _____?

A
  • doxycycline + rifampin or aminoglycoside
46
Q

Bacteria = HELICOBACTER PYLORI (G- rods)

Treat with _____?

A
  • bismuth + metronidazole + tetracycline or amaxicillin
47
Q

Bacteria = PSEUDOMONAS AERUGINOSA (G- rods)

Treat with _____?

A
  • antipseudomonal penicillin + aminoglycoside
48
Q

Bacteria = STENOTROPHOMONAS MALTOPHILIA (G- rods)

Treat with _____?

A
  • TMP-SMZ
49
Q

Bacteria = LEGIONELLA (G- rods)

Treat with _____?

A
  • azithromycin + rifampin or quinolone + rifampin
50
Q

Bacteria = STREP PNEUM (G+ cocci)

Treat with _____?

A
  • penicillin
51
Q

Bacteria = STREP PYOGENES, GROUP A (G+ cocci)

Treat with _____?

A
  • penicillin, clindamycin
52
Q

Bacteria = STREP AGALACTIAE, GROUP B (G+ cocci)

Treat with _____?

A
  • penicillin (+ aminoglycoside)
53
Q

Bacteria = VIRIDANS STREP (G+ cocci)

Treat with _____?

A
  • penicillin
54
Q

Bacteria = STAPH AUREUS, BETA LACTAMASE NEG (G+ cocci)

Treat with _____?

A
  • penicillin
55
Q

Bacteria = STAPH AUREUS, BETA LACTAMASE POS (G+ cocci)

Treat with _____?

A
  • penicillinase resistant penicillin
56
Q

Bacteria = METHICILLIN RESISTANT (G+ cocci)

Treat with _____?

A
  • vancomycin
57
Q

Bacteria = ENTEROCOCCUS SPECIES (G+ cocci)

Treat with _____?

A
  • penicillin + aminoglycoside
58
Q

Bacteria = BACILLUS SPECIES (G+ rod, aerobic)

Treat with _____?

A
  • vancomycin
59
Q

Bacteria = LISTERIA SPECIES (G+ rod, aerobic)

Treat with _____?

A
  • ampicillin (+/- aminoglycoside)
60
Q

Bacteria = NOCARDIA SPECIES (G+ rod, aerobic)

Treat with _____?

A
  • sulfadiazine

- TMP-SMZ

KG - Pharmacology (8 decks)

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