Lecture 15: Antibiotics Part 1 Flashcards

1
Q

What color does a G+ bacteria stain?

A

Purple

Mnemonic:
(more Ps = more positive)

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2
Q

What is the main shape of G+ bacteria?

A

Cocci

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3
Q

What is the only coagulase positive Staphylococcus?

A

S. aureus

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4
Q

What are the two types of paired/chained cocci?

A

Streptococcus
Enterococcus

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5
Q

What is the more resistant Enterococcus?

A

E. faecium

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6
Q

What are the two shapes of G- bacteria?

A

Cocci
Bacilli

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7
Q

What 5 bacteria form the enterobacterales?

A

E. coli
Klebsiella spp.
Enterobacter spp.
Serratia spp.
Citrobacter spp.

AKA all lactose fermenters are enterobacterales.

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8
Q

What are the 3 main enterobacterales?

A

E. coli
Klebsiella spp.
Enterobacter spp.

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9
Q

What kind of bacteria is P. aeruginosa?

A

A non-lactose fermenter.
G- bacilli.

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10
Q

What are the anaerobic bacteria?

A

G+:
Peptostreptococcus
Clostridium

G-:
Bacteroides spp.

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11
Q

What are the 3 atypical bacteria?

A

Mycoplasma
Legionella
Chlamydophilia

Note:
Pneumonia is common from all 3 of these.

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12
Q

What do pencillins and cephalosporins do for their mechanism?

A

Inhibition of cell wall synthesis.

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13
Q

What does MRSA, VRE, ESBL, and CRE stand for?

A

MRSA: methicillin-resistant S. aureus

VRE: Vancomycin resistant enterococcus

ESBL: extended spectrum beta lactamase producing organism.

CRE: Carbapenem-resistant enterobacterales.

Note:
VRE and CRE are NOT THE SAME E.

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14
Q

What is the different between narrow and broad spectrum abx?

A

Broad means multiple strain coverage.

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15
Q

What is the difference between empiric and definitive therapy?

A

Empiric is not knowing what the specific organism is, but having a good idea.

Definitive is knowing what organism you’re going to treat.

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16
Q

What is MIC?

A

Lowest concentration of an abx needed to INHIBIT growth of a bacteria.

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17
Q

What does it mean when an abx is time-dependent?

A

The time spent above the MIC. AKA as long as you meet the MIC, it’s how long you stay above it, not the dosage itself.

Note:
Applies to many of the beta-lactamases, which are G- bacteria.

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18
Q

What does it mean when an abx is dose-dependent?

A

Concentration dependent, aka the higher the dose, the higher the efficacy.

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19
Q

What is meant by beta-lactamase bacteria?

A

A bacteria capable of producing an enzyme that can break apart beta-lactams.

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20
Q

What ABX make beta lactams?

A

Penicillins
Cephalosporins
Carbapenems
Monobactams

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21
Q

What ABX category is vancomycin?

A

Glycopeptide

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22
Q

What ABX category is daptomycin?

A

Cyclic glycopeptide

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23
Q

What ABX category ends in vancin?

A

Lipoglycopeptides

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24
Q

What are all cell agents able to do to bacteria?

A

Kill them.

All agents are bactericidal.

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25
Q

Describe the MOA of a beta-lactam.

A

Bind to penicillin-binding proteins in cell walls.
Interrupts cell wall synthesis, resulting in bacterial cell lysis and death.

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26
Q

What kind of toxicity can ensue from beta-lactams in renal dysfunction?

A

CNS toxicity.

Note:
Most ABX are renally dosed as a result.

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27
Q

What kind of disturbance can ensue from oral beta-lactam use?

A

GI disturbances.

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28
Q

What drug interacts with all the beta-lactams? What does it do?

A

Probenicid.
Increases serum concentration.

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29
Q

What is efficacy measured as?

A

Time above MIC (aka time-dependent)

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30
Q

What kind of agents usually use prolonged infusions?

A

beta lactams mostly with Antipseudomonals.

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31
Q

What is the only natural pencillin?

A

The pencillins!

Penicillin VK, G, G sodium, G benzathine, G procaine/benzathine.

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32
Q

Why is benzathine added to pencillin?

A

Prolongs half-life.

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33
Q

What is a unique clinical use of natural penicillins?

A

Syphilis treatment

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34
Q

What is the reaction that occurs from natural penicillin use? What kind of reaction relationship is it?

A

Jarisch-Herxheimer reaction.

Time-related reaction.

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35
Q

What are the only two penicillins that do not require renal adjustments?

A

Nafcillin
Oxacillin

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36
Q

What is MSSA?

A

Methicillin susceptible staph A

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37
Q

What is Oxacillin preferred over Nafcillin?

A

Nafcillin has a higher incidence of acute interstitial nephritis.

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38
Q

What class are nafcillin, oxacillin, and dicloxacillin in?

A

Penicillinase-resistant Penicllins

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39
Q

What are the two aminopenicillins?

A

Amoxicillin
Ampicillin

Note:
They start with A.

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40
Q

What specific bacteria are aminopenicillins used for?

A

Enterococcus spp.

They are the drug of choice.

Note:
If it is VRE, they are generally resistant to penicillins as well.

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41
Q

What is the only extended spectrum penicillin?

A

Piperacillin

No longer on market as a solo drug.

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42
Q

What is the bonus of having an Extended spectrum S penicillin over a regular one?

A

Additional G- coverage.

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43
Q

What was piperacillin originally intended for?

A

Antipseudomonal!

AKA it works against P. aeruginosa.

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44
Q

What is a beta-lactamase inhibitor? Why is it clinically significant?

A

Prevents hydrolytic action on penicillin and binds directly to penicillin-bind proteins to increase abx activity.

Note:
Bacteria can make beta lactamases, which can cleave some abx and disable them.

45
Q

What are the 3 beta-lactamase inhibitor combinations for penicillins?

A

Amoxicillin/clavulanic acid
Ampicillin/sulbactam
Piperacillin/tazobactam

AKA the aminopenicillins and extended spectrum penicillin.

46
Q

What does adding a beta-lactamase inhibitor do to a antibiotic’s coverage?

A

Increased G- coverage
Increase anaerobe coverage

47
Q

Which beta-lactamase inhibitor combination can cover the acinetobacter spp?

A

Ampicillin/Sulbactam

48
Q

What kind of antibiotic is a cephalosporin?

A

Beta-lactam abx

49
Q

What generally happens as the cephalosporin generation increases? (AKA 1st gen is less than 3rd gen)

A

Increased G- coverage
Increased CNS penetration (aka able to treat meningitis)

50
Q

If someone has a penicillin allergy, can I give a cephalosporin?

A

Yes (mostly)
Cross-reactivity is only about 1%.

51
Q

What are the 3 first-gen cephalosporins?

A

Cefazolin
Cephalexin
Cefadroxil

52
Q

What are first-gen cephalosporins mainly used for?

A

MSSA

53
Q

What penicillin do I use for more minor MSSA?

A

Oxacillin

54
Q

What are the 2nd gen cephalosporins?

A

Cefotetan
Cefoxitin
Cefprozil
Cefaclor
Cefuroxime

55
Q

Which 2nd gen cephalosporin can interact with warfarin?

A

Cefotetan

Note:
It has a MTT side chain.

56
Q

What two 2nd gen cephalosporins have anaerobic activity?

A

Cefotetan
Cefoxitin

57
Q

What is cefuroxime usually used for?

A

Respiratory tract infections

58
Q

What are the 3rd gen cephalosporins?

A

Cefdinir
Cefpodoxime
Cefixime
Ceftriaxone
Ceftazidime
Cefotaxime

59
Q

What is the only 3rd gen cephalosporin with antipseudomonal activity?

A

Ceftazidime

60
Q

What is the only 3rd gen cephalosporin with POOR G+ activity?

A

Ceftazidime

61
Q

What is the only 4th gen cephalosporin?

A

Cefepime

62
Q

What is unique/significant about cefepime?

A

Antipseudomonal activity
Acenitobacter spp.

NO ANAEROBIC activity

63
Q

What is the only MRSA-active cephalosporin?

A

Ceftaroline

It is the only beta-lactam that works vs MRSA.

64
Q

What is Ceftolozane/tazobactam used for?

A

difficult to treat/ multidrug resistant psuedomonas (p. Aeruginosa)

also strep for G+
and enterobacterales for G-

Note:
Requires 2x dosage if treating pneumonia.

65
Q

What is ceftazidime/avibactam used for?

A

Mainly used for CRE
Can be used on MDR pseudomonas (p. aeruoginosa)

66
Q

What kind of cephalosporin is cefiderocol?

A

Siderophore cephalosporin

Note:
Chelates ferric ions and utilizes bacterial ion transport like a trojan horse.

67
Q

What can cefiderocol be used on?

A

CREs
Psuedomonas / P. aeruoginosa (not as preferred)

68
Q

What are the 4 carbapenems?

A

Doripenem
Imipenem/cilastatin
Meropenem
Ertapenem

69
Q

Why is cilastatin added to imipenem?

A

To prevent breakdown.

70
Q

What kind of spectrum do carbapenems cover?

A

Broad.
Includes G+, G- and anaerobes.

71
Q

What are the two preferred agents in the carbapenems?

A

Imipenem/cilastatin
Meropenem

72
Q

In what kind of bacteria are carbapenems the drug of choice?

A

ESBLs

73
Q

Which carbapenem has NO pseumondas or acinetobacter coverage?

A

Ertapenem

74
Q

What kind of adverse effect should I be careful/monitor with carbapenem use?

A

Seizures, mainly with imipenem/cilastatin use.

Note:
1% cross-reactivity with PCN allergy as well.

75
Q

What abx can decrease valproic acid levels?

A

Carbapenems

76
Q

What are the two carbapenem/beta-lactamase inhibitors?

A

Meropenem/vaborbactam
Imipenem/relebactam

77
Q

Why are carbapenem/beta-lactamase inhibitors used?

A

Used vs CRE.

Imipenem/relebactam can be used vs CR pseudomonas.
No added activity vs acinetobacters.

78
Q

What abx falls under the monobactams?

A

Aztreonam

79
Q

What is aztreonam used for?

A

G- only coverage.
includes most G- except acinetobacter.

Note:
Sometimes used in place of penicillin

80
Q

What abx is a glycopeptide?

A

Vancomycin.

81
Q

What is the MOA of vancomycin?

A

Blocks peptidoglycan synthesis, inhibiting bacterial cell wall synthesis.

82
Q

What does vancomycin cover?

A

G+ (INCLUDING MRSA)

83
Q

What is PO vanco used for?

A

C. Diff (must be PO, IV vanco does nothing to C. diff)

84
Q

Why is vanco almost always given IV?

A

Extremely poor bioavailability if enterally.

85
Q

What kind of reaction is a red-man syndrome?

A

Infusion reaction.

It is a result of vancomycin being given too fast, not allergy.

86
Q

What drugs can cause nephrotoxicity?

A

Piperacillin/bactam
Vancomycin

87
Q

Do I monitor trough or AUC/MIC ratio with vancomycin?

A

AUC/MIC ratio. (400-600 best)

88
Q

What abx is a cyclic glycopeptide?

A

Daptomycin

89
Q

What is the MOA of a cyclic glycopeptide?

A

Binds to components of cell membrane, causing rapid depolarization to inhibit DNA, RNA, and protein synthesis.

90
Q

What is daptomycin used for?

A

G+ coverage, including MRSA.
Also works vs VRE.

It has a similar efficacy to vanco with better tolerance.

91
Q

What is unique about daptomycin’s PK?

A

Inactivated by pulmonary surfactant. AKA if the MRSA is in the lungs, it won’t do anything.

92
Q

What abx category is telavancin?

A

Lipoglycopeptide

93
Q

What is the MOA of telavancin?

A

Inhibits cell-wall synthesis, blocking polymerization and cross-linking of peptidoglycan.

94
Q

What is the coverage of telavancin?

A

G+ only, including MRSA.

95
Q

When do I use telavancin?

A

Second-line for all indications.

96
Q

What kind of adverse effects does telavancin have?

A

Increased SCr (less effective if CrCl < 50)

Red man syndrome

Artificially prolongs PT/INR, aPTT, factor Xa

97
Q

What kind of drug interactions does telavancin have?

A

QT-prolongation

98
Q

What kind of abx are dalbavancin and oritavancin?

A

Lipoglycopeptides

99
Q

What is the MOA of dalbavancin and oritavancin?

A

Binds to cell wall peptidoglycan/precursors preventing cross-linking and interfering with cell wall synthesis.

100
Q

When is oritavancin used?

A

Good against VREs.

101
Q

What is unique about the PK of dalbavancin and oritavancin?

A

VERY LONG half-lives.

Able to dose weekly or one time.

Sometimes given 2 doses for 6 weeks.

Currently in DOTS trial.

102
Q

Which of the lipoglycopeptides has similar infusion reactions to vancomycin?

A

all 3!

They can all have red man syndrome.

103
Q

Which of the lipoglycopeptides has a similar rate of nephrotoxicity as vancomycin?

A

Dalbavancin

104
Q

What do I need to be careful in terms of drug interactions with Oritavancin?

A

MAJOR CYP inducer and inhibitor.

You cannot give IV unfractionated heparin for 5 days after giving oritavancin.

105
Q

What are the cell membrane agents?

A

Colistin, polymixin E
Polymixin B

106
Q

What is the MOA of a cell membrane agent?

A

Damages cell membrane, allowing leakage of cell contents.

107
Q

What spectruma re the cell membrane agents?

A

G- only.
ONLY USED FOR MDR resistant organisms, such as P. aeruginosa and A. baumannii

108
Q

What kind of toxicities can cell membrane agents cause?

A

Nephro
Neuro