LEC 16,17 - Inhibitors of Cell Wall Synthesis Flashcards

1
Q

What are the beta-lactam antibiotics?

A

Penicillin

Cephalosporin

Carbapenems

Monobactams

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2
Q

What is polymixin used for?

A

Topically to treat Gram (-) infections in skin + eye + ear

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3
Q

What are the five ways that a bacteria can become resistant to pencillin?

A

Inactivation

Decreased permeability

Alteration to PBP

Autolytic enzymes not activated

Lack of Cell wall

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4
Q

What must imipenem be given with? Why?

A

Cilastatin

Rapidly inactivated by renal tubule dehydropeptidases. Cilastatin is a dehydropeptidase inhibitor

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5
Q

What is the general activty of ertapenem?

A

Wide variety of

gram+

gram-

anaerobic

Eneterobateriaceae

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6
Q

bacterial target of pencillinase resistant penicillins

A

Low activity againse certain gram +’s

Resistant to penicllinase

DOC - penicillinase producing Staphylocccocus areus

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7
Q

Which of the natural penicillins are resistant to gastric acid?

A

Penicillin V

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8
Q

How does B-lactamase stop B-lactams from being active?

A

Cleaves the B-lactam ring

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9
Q

What is the general activity of carbaenems?

A

Broad spectrum

Anaerobes

Gram (+)

Gram (-) rods

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10
Q

Antipseudomonal penicillins (2)

A

Piperacillin

Ticarcillin

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11
Q

How are cephalosporins excreted?

A

Unchanged by the kindey

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12
Q

What are your two atypical bacteria?

A

Chlamydia

Mycoplasma

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13
Q

What are the specific bacteria that 1st gen cephalosporins are good against?

A

E. Coli

Klebsiella pneumoniae

Proteus mirabilis

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14
Q

How do the glycopeptides work?

A

Sterically inhibit addition of subunits to the peptidoglycan backbone

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15
Q

What are the bacterial targets of antipseudomonal penicillins?

A

Those covered by extended spectrum penicillins + addition gram negative bacilli

NO KLEBSIELLA

Major treatment for Pseudomonas aeruginosa

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16
Q

What is the function of the cell wall in bacteria?

A

Bacteria are hyperosmolar to their environment. The cell wall prevents osmotic rupture

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17
Q

What is the adverse effects of imipenem?

A

Seizures can occur with high levels

Use carefully in patients with brain lesion, head trauma , or hx of CNS disorders

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18
Q

What is the general structure of gram positive bacteria?

A

Only layered structure external to cell membrane and is thick

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19
Q

Route of Admin - Pen G procaine

A

IM

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20
Q

What cephalosporin is the only one allowed in food animals?

A

Cephapirim

Cows, pigs, turkey, and chickens

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21
Q

Use - Ceftiofur

A

Respiratory infections

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22
Q

What is the big difference between bacteria and mammialian cells?

A

Rigid cell wall external to the cell membrane

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23
Q

How is vancomycin excreted?

A

Primarily unchanged via the kidney

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24
Q

What is Penicillin G not effective against?

A

Amoebae

Plasmodia

Rickettsiae

Fungi

Virus

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25
Q

Route of Admin - Pen G potassium

A

IV + IM

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26
Q

What is the real reason behind the loss of cell-wall integrity following treatment of CWSi?

A

Bacteria’s own cell wall remodeling enzymes aka autolysins

Cleave peptidoglycan bonds

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27
Q

If choosing carbapenems for a pseudomonas infection how is recommended to be given? WHy?

A

resistance occurs quickly

Give with aminoglycoside

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28
Q

Carbapenems (3)

A

Imipenem

Meropenem

Ertapenem

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29
Q

What is the rank of antipseudomonal activity?

A

Piperacillin > Ticarcillin

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30
Q

When should doses of cephalosporin be adjusted?

A

Renal impairment

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31
Q

Penicillinase ressitant penicillins (3)

A

Oxacillin

Cloxacillin

Methicillin

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32
Q

How does bacitracin work?

A

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

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33
Q

Use - Cefovecin

A

Skin and soft tissue infections

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34
Q

What is a very important thing to remember about monobactams (aztreonam) when it comes to theraputic use?

A

No cross sensitivty with penicillin, can give it to those who are allergic

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35
Q

B-lactamase inhibitor combo - Piperacillin

A

Tazobactam

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36
Q

What are the adverse effects of monobactams?

A

Phlebitis

Skin rash

Abnormal liver function

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37
Q

Route of Admin - Penicillin V

A

Oral

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38
Q

Use - Cefpodoxime

A

Skin and soft tissue infections in dogs

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39
Q

Natural penicillins (4)

A

Penicillin G potassium

Penicillin G benzathine

Penicillin G procaine

Pencillin V

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40
Q

How are natural penicillins excreted?

A

Active transport in the kidney

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41
Q

What is vancomycin useful against?

A

Penicillin + methicillin resistant staphylococcus aureus

Treating gram (+) infections in penicillin allergic patients

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42
Q

how can you prolong the time penicillin stays in the body? How does it work?

A

Give probenecid

Tubular secretion partially blocked by probenecid

Used for severe infections

43
Q

Can you take antipseudomonals orally?

A

Acid sensitive

44
Q

Where is PBP located?

A

On the cytoplasmic membrane

45
Q

What are the three groups of polymyxins?

A

Monobactams

Carbapenems

Others…

46
Q

Where is the antibacterial activity located in penicillin?

A

Intact B-lactam ring

47
Q

What are the symptoms of penicillin toxicity?

A

Mostly just allergic reactions

Anaphylactic

Cytotoxic

Arthus

Cell mediated

48
Q

What are the the six major groups of drugs that inhibit cell wall formation?

A

Polymyxins

Natural penicillins

Penicillinase

Resistant penicillins

Extended spectrum penicillins

Antipseudomonal penicillins

Cephalosporins

49
Q

1st gen cephalosporins (4)

A

Cefazolin

Cefadroxil

Cephalexin

Cephapirim

50
Q

What is the general activty of 4th gen cephalosporins?

A

More resistant to B-lactamases

51
Q

What do B-lactamase inhibitors not work against?

A

Methicillin-resistant, penicillinase-producing, Staphylococci

52
Q

What is the structure of the bacterial cell wall?

A

Resistant to osmotic lysis in both gram positive and gram negative due to peptidoglycan

Convalently linked sacculus that surrounds bacterium

53
Q

What are the two ways vancomycin inhibits cell wall synthesis?

A

1 - binding to D-ala-D-ala terminus of peptidoglcan peptide = prevention of crosslinking

2- inihibits transglycosylation which inhibits elongation of peptidoglycan and chain

54
Q

What does resistance form against vancomycin?

A

1 - D-ala-D-ala replaced with D-ala-D-lactate

55
Q

B-lactamase inhibitor combo - Amipicillin

A

Sulbactam

56
Q

What is the upside to using ertapenem?

A

Highly stable against beta-lactamases

57
Q

What are the gram - bacteria that are targeted by extended spectrum penicillins? (5)

A

E. Coli

Salmonella

Shigella

H. influenzae

Proteus

58
Q

What is the major characteristic of penicillin excretion?

A

one of the fastest drugs to be excreted renally

59
Q

Why is polymixin not used parenteral?

A

Too nephrotoxic

60
Q

Use for cefazolin

A

surgical prophylaxis

61
Q

What is the mechanism by which bacitracin works?

A

Interferes with final dephosphorylation step in the phospholipid carrier cycle

Impedes on mucopeptide transder to growing cell wall

62
Q

Why is parenteral bacitracin used with extereme caution?

A

Serious nephrotoxicity

63
Q

What is the general structure of gram negative bacteria?

A

Outer membrane external to very thin peptidoglycan layer

64
Q

How is bacitracin most commonly used?

A

Prevent superficial skin + eye infections following minor injuries

65
Q

What is polymixin B normally combined with?

A

Bacitracin for broad spectrum antibacterial effects

66
Q

What are the gram + exceptions to 1st gen cephalosporin susceptibility?

A

Enterococci

MRSA

67
Q

What is the requirement for biological activity of penicillin?

A

Penicillin nucleus

68
Q

What are the extra bacterial targets of the antipseudomonal pencillins?

A

Proteus

Enterobacter

69
Q

What is the general activity of 2nd gen cephalosporins?

A

Increased activity against gram (-)

70
Q

4th gen cephalosporin (1)

A

Cefepimes

71
Q

What drugs are contraindicated when using CWSi?

A

Protein synthesis inhibitors

72
Q

What is the general activity of 1st gen cephalosporins?

A

good activity - gram + (cocci most)

moderate activity - gram -

73
Q

What is the mechanism of action for polymixin B?

A

Interacts with phospholipids in bacterial cell wall membrane to produce a detergent-like effect + membrane disruption

74
Q

What are the four things that cephalosporins do not work against?

A

MRSA

Listeria monocytogene s

Enterococci

Atypicals

75
Q

What group of bacteria are ICWS most effective against?

A

Gram +

76
Q

How is penicillin excreted?

A

10% glomerular filtration

90% tubular secretion

77
Q

B-lactamase inhibitor combo - Ticarcillin

A

Calvulanic Acid

78
Q

When is polymixin B administered orally?

A

Cattle + Swine

Treatment of Gram (-) enteric infections

79
Q

When can polymixin B be used parenterally?

A

Severe cases in horses

80
Q

Extended spectrum penicillins (2)

A

Ampicillin

Amoxicillin

81
Q

How is resistance to b lactamase inhibitors occurring?

A

Develope independently upon b-lactamase production

altered PBP production

82
Q

What is the general activity of 3rd gen cephalosporins?

A

less active against gram + cocci

more active against Enterobacteriaceae

83
Q

How do b-lactams function?

A

Prevent cross-linking reaction called transpeptidation

84
Q

How do the CWS inhibitors cause cell death?

A

Osmotic lysis

85
Q

Route of Admin - Pen G bezathine

A

IM

86
Q

What is the general activity of Bacitracin?

A

Gram (+)

87
Q

What bacteria lack a cell wall?

A

Mycoplasma L forms

Chlamydia

88
Q

What are the regulations of vancomycin use in food animals

A
89
Q

Monobactams (1)

A

Aztreonam

90
Q

2nd gen cephalosporin

A

Cefoxitin

Cefaclor

91
Q

What are the bacterial targets of extended spectrum penicillin?

A

Lower gram + coverage

Extended gram - coverage

Anaerobic coverage (w/ penicillinase inhibitors)

92
Q

What are the adverse reactions to vancomycin?

A

Hypersensitivty

Ototoxic

Nephrotoxic

Uremia

93
Q

What are the bacteria that do not have the autolytic enzymes activate and therefore are tolerant to penicillin?

A

Listeria

Staphylococci

94
Q

What does vancomycin have synergistic effects against?

A

Aminoglycosides

95
Q

What are the glycoeptides?

A

Vancomycin

96
Q

Use - Cefixime

A

Skin + Soft tissue + Urinary infections

97
Q

What is the general activity of monobactams?

A

Relatively resistant to beta-lactamases

Active against gram(-) rods (pseudomonas)

No activity against gram + or anaerobes

98
Q

What are the drugs the b lacatamase inhibitors are added with?

A

Ampicillin

Amoxicillin

Ticarcillin

Pipercillin

99
Q

What specific bacteria do ICWS work the best against?

A

Pseudomonas aeruginosa

100
Q

B-lactamase inhibitor combo - Amoxicillin

A

Clavulanic acid

101
Q

When is polymixin B bactericidal?

A

Gram (-) organism

102
Q

What are the three B-lactamase inhibitors?

A

Clavulanic acid

Sulbactam

Tazobactam

103
Q

Two other cell wall synthesis inhibitors that are not in groups

A

Vancomycin

Bacitracin

104
Q

3rd gen cephalosporins

A

Ceftiofur

Cefovecin

Cefixime

Cefpodoxime