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Flashcards in Penicillin Deck (60):
1

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

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

2

what are peptidoglycans composed of?

- backbones of two alternating sugars
- chain of 4 amino acids
- peptide bridge that cross links the tetra peptide chains

3

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

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

4

how are peptidoglycans formed?

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

5

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

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)

6

what does fosfomycin do?

inhibits one of the first steps in synthesis of peptidoglycan

7

what does cycloserine do?

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

8

what does bacitracin do?

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

9

what do glycopeptides (vancomycin) do?

sterically inhibit addition of subunits to peptidoglycan backbone

10

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

prevent cross linking reaction called transpeptidation

- performed by transpeptidases or PBPs

11

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

virtually all = bactericidal

12

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

osmotic lysis

13

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

autolysins

14

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

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

15

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

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

16

what are properties of ICWS?

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

17

list: Beta lactams

- penicillins
- cephalosporins
- monobactams
- carbapenems

18

list: other inhibitors of CWS (not beta lactams)

- vancomycin
- fosfomycin
- bacitracin
- cycloserine

19

list: penicillins --> natural penicillins

- PENICILLIN G (prototype)
- benzathine penicillin
- procaine penicillin G
- penicillin V

20

list: penicillins --> penicillinase

- NAFCILLIN (prototype)
- docloxacillin
- oxacillin
- *Methicillin

21

list: penicillins --> extended spectrum

- AMPILLIN (prototype)
- amoxicillin
- bacamicillin

22

list: penicillins --> antipseudomonal

- PIPERACILLIN (prototype)
- ticarcillin
- mezlocillin
- carbeicillin

23

info about NATURAL PENICILLINS

- 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

24

how can the natural pencillins be administered?

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

25

info about PENICILLINASE resistant penicillins

- 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

how can PENICILLINASE be administered?

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

*** Metacillin = testing only!

27

MRSA mechanism of resistance?

- 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

info about EXTENDED SPECTRUM penicillins

- 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

how can EXTENDED SPECTRUM penicillins be administered?

- AMPICILLIN = oral
- amoxicillin = oral

30

which rash is NOT a hypersensitivity rash?

ampicillin, usu corresponds w/ hx of EBV

31

info about ANTIPSEUDOMONAL penicillins

- 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

which group of penicillins should you NEVER use alone?

antipseudomonal penicillins

33

how can ANTIPSEUDOMONAL penicillins be administered?

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

- PIPERACILLIN
- ticarcillin
- mezlocillin
- carbenicillin

34

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

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

Unasyn = _______ + _______

Unasyn = ampicillin + sulbactam

- IV, IM

36

augmentin = _______ + _______

augmentin = amoxicillin + clavulanic acid

- oral

37

zosyn = _______ + _______

zosyn = piperacillin + tazobactam

- IV

38

timentin = _______ + _______

timentin = ticarcillin + clavulanic acid

39

what are reasons of bacterial resistance to penicillins?

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

what are examples of allergies resulting from penicillins?

- allergy, all forms (not ampicillin rash)
- electrolyte imbalance
- GI probs
- superinfections

41

pharmacokinetics of penicillins

- good tissue penetration
- poor CNS penetration
- mostly renal elimination
- filtration/tubular excretion
- probenecid inhibits renal elimination

42

Bacteria = ENTEROBACTER, CITROBACTER, SERRATIA (G- rods)
Treat with _____?

- TMP-SMZ
- quinolone
- carbapenem

43

Bacteria = SHIGELLA (G- rods)
Treat with _____?

quinolone

44

Bacteria = SALMONELLA (G- rods)
Treat with _____?

- TMP-SMZ
- quinolone
- cephalosporine (3rd gen)

45

Bacteria = BRUCELLA SPECIES (G- rods)
Treat with _____?

- doxycycline + rifampin or aminoglycoside

46

Bacteria = HELICOBACTER PYLORI (G- rods)
Treat with _____?

- bismuth + metronidazole + tetracycline or amaxicillin

47

Bacteria = PSEUDOMONAS AERUGINOSA (G- rods)
Treat with _____?

- antipseudomonal penicillin + aminoglycoside

48

Bacteria = STENOTROPHOMONAS MALTOPHILIA (G- rods)
Treat with _____?

- TMP-SMZ

49

Bacteria = LEGIONELLA (G- rods)
Treat with _____?

- azithromycin + rifampin or quinolone + rifampin

50

Bacteria = STREP PNEUM (G+ cocci)
Treat with _____?

- penicillin

51

Bacteria = STREP PYOGENES, GROUP A (G+ cocci)
Treat with _____?

- penicillin, clindamycin

52

Bacteria = STREP AGALACTIAE, GROUP B (G+ cocci)
Treat with _____?

- penicillin (+ aminoglycoside)

53

Bacteria = VIRIDANS STREP (G+ cocci)
Treat with _____?

- penicillin

54

Bacteria = STAPH AUREUS, BETA LACTAMASE NEG (G+ cocci)
Treat with _____?

- penicillin

55

Bacteria = STAPH AUREUS, BETA LACTAMASE POS (G+ cocci)
Treat with _____?

- penicillinase resistant penicillin

56

Bacteria = METHICILLIN RESISTANT (G+ cocci)
Treat with _____?

- vancomycin

57

Bacteria = ENTEROCOCCUS SPECIES (G+ cocci)
Treat with _____?

- penicillin + aminoglycoside

58

Bacteria = BACILLUS SPECIES (G+ rod, aerobic)
Treat with _____?

- vancomycin

59

Bacteria = LISTERIA SPECIES (G+ rod, aerobic)
Treat with _____?

- ampicillin (+/- aminoglycoside)

60

Bacteria = NOCARDIA SPECIES (G+ rod, aerobic)
Treat with _____?

- sulfadiazine
- TMP-SMZ