Antibiotic Review Flashcards

1
Q

How to select an antibiotic?

A
  1. What bacteria are you trying to target?
  2. What is the antibiotic spectrum of coverage?
  3. Are there any contraindications or side effects to consider?
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2
Q

Characteristics of gram positive bacteria?

A

Thick cell wall
2-layer envelope
NO porin channel
NO endotoxin
Vulnerable to lysozyme and PCN

*Lyzozyme: small enzyme that attacks cell walls of bacteria, part of natural immune system
**Gram positive bacteria stain purple on gram stain

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3
Q

Characteristics of gram negative bacteria?

A

Thin cell wall
3-layer cell envelope
Porin channel
Resistant to lysozyme and PCN

**stains pink/red on gram stain

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4
Q

Gram + vs. gram - cell wall picture (flip for reference)

A
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5
Q

Types of aerobic gram positive organisms

A

Streptococcus
Staphylococcus
Enterococcus
Corynebacterium
Listeria

Aerobbic gram positive organisms have enzymes to break down O2 (unlike anaerobes), therefore, blood cultures are taken in 2 tubes (1 w/ oxygen and 1 w/o)

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6
Q

Types of anaerobic gram positive organisms

A

Peptococcus
Peptostreptococcus
Clostridia (C. diff)
Propionibacterium acnes

Anaerobic gram positive organisms are associated with acne, above diaphragm, tooth abscess

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7
Q

Types of aerobic gram negative organisms

A

Enterobacteriaceae (E coli, Klebsiella, Proteus, Enterobacter, Serratia, Providencia, Salmonella, Shigella, Morganella, Citrobacter)
Moraxella
Haemophilus
Neisseria
Pseudomonas
Helicobacter
Legionella

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8
Q

Types of anaerobic gram negative organisms

A

Bacteroides
Fusobacterium

Of note: anaerobics generally below diaphragm (diabetic foot ulcers, etc)

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9
Q

Types of atypical organisms (neither gram + or gram -)

A

Chlamydia
Chlamydophila
Rickettsia
Mycoplasma (no cell wall)
Spirochetes (Syphilis, Lyme Disease)
Mycobacterium (TB, mycobacterium avium intracellulare)

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10
Q

What are the 3 main MOAs for most antibiotics?

A

Inhibit cell wall production, inhibit protein synthesis (30s or 50s ribosome), inhibit DNA synthesis

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11
Q

Examples of antibiotics that inhibit cell wall synthesis

A

Beta-Lactams
(Penicillins, Cephalosporins, Carbapenems)

Vancomycin

Glycopeptides

Fosfomycin

Bacitracin

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12
Q

Examples of antibiotics that inhibit protein synthesis

A

Macrolides (50s)

Ketolides (50s)

Oxazolidinones (50s)

Clindamycin (50s)

Aminoglycosides (30s)

Tetracyclines (30s)

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13
Q

Examples of antibiotics that inhibit DNA synthesis

A

Fluoroquinolones (topoisomerase)

Sulfamethoxazole/Trimethoprim (folic acid antagonist)

Rifampin (RNA polymerase)

Metronidazole “alters” DNA

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14
Q

What are some bactericidal antibiotics (“kills the bacteria”)?

A

Beta Lactams

Fluoroquinolones

Glycopeptides

Aminoglycosides

Metronidazole

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15
Q

What are some bacteriostatic antibiotics (“prevents the growth of bacteria”)?

A

Tetracyclines

Macrolides

Lincosamides

Sulfonamides

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16
Q

Spectrum of penicillins?

A

Gram-positive (S. pneumo and Staph resistance), gram-negative, anaerobes

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17
Q

AEs of penicillin?

A

Hypersensitivity, GI, hematological, seizures

Mostly renal elimination (adjust if CKD) EXCEPT nafcillin (hepatic)

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18
Q

Describe examples, spectrum, and use of natural penicillins

A

Pen G, Pen VK, Procaine, Benzathine

Spectrum: T. pallidum, streptococcus,
enterococcus,
Neisseria meningitidis,
Borrelia burgdorferi (all gram +)

Use: Syphilis, Strep pyogenes, Lymes

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19
Q

Describe examples, spectrum, and use of anti stapholococcal penicillins

A

Dicloxacillin, Nafcillin, Oxacillin, Methicillin

Spectrum: Staphylococcal and streptococcal infections (all gram +)

Use: MSSA, skin infections (mastitis)

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20
Q

Describe examples, spectrum, and use of amino penicillins

A

(IV Ampicillin, PO Amoxicillin)

Spectrum: GAS, GBS, enterococci, listeria, Borrelia burgdorferi, H. pylori (all gram +)

Use: Respiratory tract infections, Lymes, GI ulcers, UTI, endocarditis prophylaxis*

Amox + Mono = maculopapular rash*

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21
Q

Describe examples, spectrum, and use of extended spectrum penicillins

A

Piperacillin, Ticarcillin

Spectrum: Gram positives and negatives including pseudomonas

Use: IV only, serious infections

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22
Q

Examples agents of beta-lactamase inhibitors

A

Oral = amoxicillin/clavulanate (Augmentin)
IV = ampicillin/sulbactam (Unasyn), piperacillin/tazobactam (Zosyn), ticarcillin/clavulanate (Timentin)

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23
Q

Spectrum, use, and AEs of beta-lactamase inhibitors?

A

Spectrum: extends spectrum to beta-lactamase producing organisms (Staph aureus, Moraxella Haemophilus, Neisseria, Bacteroides, Enterobacteriaceae)

Use: Amox-clav = respiratory tract infections, dental infections, animal bites, skin infections

AE: diarrhea (clavulanate)

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24
Q

Example agents of first generation cephalosporins?

A

Oral: cephalexin (Keflex)
Parenteral: cefazolin (Ancef)

All have ph except Cefazolin, but don’t let that faze you

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25
Q

Spectrum and use of first generation cephalosporins?

A

Spectrum: Gram positives (staph/strep), MSSA, limited gram negatives (E. coli, Klebsiella), oral anaerobes

Use: Skin infections, streptococcal infections, pre-op prophylaxis

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26
Q

Example agents of second generation cephalosporins?

A

Oral: cefuroxime (Ceftin)
Parenteral: cefuroxime, cefoxitin, cefotetan

The family is gathered, some wearing fur coats, and your foxy cousin is drinking tea

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27
Q

Spectrum and use of second generation cephalosporins?

A

Spectrum: Less gram positive, more gram negative than first generation. H influenzae, Moraxella, Neisseria, Enterobacter, Borrelia burgdorferi.

Use: Respiratory tract infections, UTI, Lyme, skin infections

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28
Q

Example agents of third generation cephalosporins?

A

PO: cefpodoxime, cefixime, cefdinir (Omnicef), ceftibuten

IV: ceftriaxone (Rocephin)

Most end in the suffix -me. Dine Alone (Cedinir and Ceftriaxone)

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29
Q

Spectrum and use of third generation cephalosporins?

A

Spectrum: Less gram +, more gram - **(including pseudomonas) **

Use: Respiratory, skin (not great), UTI, gonorrhea, meningitis

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30
Q

Example agents of fourth generation cephalosporins?

A

IV: cefepime (Maxipime)

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31
Q

Spectrum and use of fourth generation cephalosporins?

A

Spectrum: **Gram + and - coverage (including Pseudomonas) **

Use: Unknown cause of infection pending blood cultures

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32
Q

Example agents of fifth generation cephalosporins?

A

IV: ceftaroline

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33
Q

Spectrum and use of fifth generation cephalosporins?

A

Spectrum: Gram + and - coverage (NOT including Pseudomonas) **

Use: MRSA and resistant S. pneumoniae

“Think Ceftriaxone + MRSA coverage”

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34
Q

MOA of carbapenems?

A

Inhibits cell synthesis

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35
Q

Carbapenem agents?

A

Imipenem, meropenem, ertapenem (ALL IV)

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36
Q

Spectrum and AEs of carbapenems?

A

Spectrum: VERY BROAD (includes ESBL organisms)

“Heavy hitters”

**Ertapenem is the only carbapenem with NO pseudomonas coverage (narrower spectrum)

ESBL: extended-spectrum beta-lactamases

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37
Q

AEs of carbapenems?

A

Hypersensitivity (penicillins), GI, seizures, hypotension

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38
Q

MOA of monobactams?

A

Inhibit cell wall synthesis

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39
Q

Monobactam agents?

A

IV only aztreonam

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40
Q

Spectrum of monobactams?

A

Spectrum: aerobic gram negative only (including Pseudomonas)

“Heavy hitters”

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41
Q

AEs of monobactams?

A

GI

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42
Q

Aztreonam pearls

A

Similar to aminoglycosides
Little cross reactivity with PCN allergies
Note renal dosing
Is not often used unless allergic to something else

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43
Q

Fluoroquinolone MOA?

A

Inhibits DNA synthesis (topoisomerase - inhibit twisting of DNA)

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44
Q

FQ agents?

A

Ciprofloxacin, ofloxacin, levofloxacin, moxifloxacin

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45
Q

FQ spectrum?

A

Gram + (moxifloxacin)

Gram - (cipro and levo)

Pseudomonas, atypicals (Chlamydia, Mycoplasma)

46
Q

FQ use?

A

Good tissue penetration (bone and prostate), respiratory tract infections, UTIs (not first line), pyelonephritis, GI (Salmonella, Shigella, traveler’s diarrhea), PID, urethritis, cervicitis

47
Q

FQ AEs?

A

AEs: QT prolongation, cartilage toxicity in pediatrics (avoid < 18 yo), avoid during pregnancy, photosensitivity, increased LFTs, hypo/hyperglycemia

BBW: tendinitis/tendon rupture, peripheral neuropathy, exacerbation of myasthenia gravis, CNS (hallucinations, depression and anxiety)

48
Q

FQ drug interations?

A

Drugs affecting QT interval and/or blood glucose, theophylline, warfarin (increases INR)

49
Q

FQ pearls

A

Renal and hepatic elimination

Try to use something else before jumping to FQ

Hold vitamins (such as Iron or Zinc) - binds to FQs and are not absorbed as well

50
Q

Macrolide MOA?

A

Inhibit protein synthesis

51
Q

Macrolide agents?

A

Erythromycin, clarithromycin, azithromycin

52
Q

Macrolide spectrum?

A

Gram positive

Gram negative (no Pseudomonas/Enterobacteriaceae)

Atypicals (Mycoplasma, Chlamydia, Rickettsia, Legionella)

53
Q

Macrolide use?

A

Respiratory tract infections, Lyme, H pylori, chlamydia, gonorrhea

54
Q

Macrolide AEs?

A

GI (stimulates motility), ototoxicity, prolongs QT interval

Inhibits cytochrome P450 = many drug interactions (ex. warfarin, statins)

Hepatic elimination

55
Q

Macrolide pearl

A

Good if PCN allergies

Azithromycin longer half life. That’s why only dose for 5 days (half life 2-4 days).

Erythromycin = more narrow spectrum

56
Q

Tetracycline MOA?

A

Protein synthesis inhibitors

57
Q

Tetracycline agents?

A

Tetracycline, doxycycline, minocycline

58
Q

Tetracycline spectrum?

A

P. acne, H. pylori, Rickettsia, Chlamydia, Mycoplasma, B. burgdorferi, T. pallidum, MRSA

Good for atypicals

59
Q

Tetracycline uses?

A

Acne, respiratory tract infections, community-acquired pneumonia, Lyme disease, GI ulcers, Rocky Mountain Spotted Fever, chlamydia, community-acquired MRSA

60
Q

Tetracycline AEs?

A

Photosensitivity, deposition in teeth/bone (AVOID in pregnancy, OK in children < 8 yo for < 21 days), hepatotoxicity, transient vestibular dysfunction (minocycline)

Chelation of Mg and Zinc, warfarin

AVOID with isotretinoin, risk of pseudotumor cerebri

61
Q

Aminoglycoside MOA?

A

Protein synthesis inhibitors

62
Q

Aminoglycoside agents?

A

IV ONLY: gentamicin, tobramycin, amikacin

63
Q

Aminoglycoside spectrum?

A

Aerobic gram-positives and negatives (including Pseudomonas aeruginosa)

“Heavy hitters”

64
Q

Aminoglycoside use?

A

Generally gram negative infections in hospital

Used for empiric therapy of serious infection

65
Q

Aminoglycoside AEs?

A

Nephrotoxicity (acute tubular necrosis), ototoxicity (SN hearing loss), neuromuscular blockade

66
Q

Aminoglycoside monioring?

A

Yes

Monitor serum concentrations (renally excreted)

67
Q

Aminoglcoside pearls

A

Streptomycin = highly toxic, rarely used

AVOID for patients on loop diuretics as both increase risk of ototoxicity

Aminoglycosides: decrease release of ACh in synapse and act as a neuromuscular blocker, this is why it can enhance effects of muscle relaxants

Most often used in combination, syndergistic effect with agents that affect cell wall integrity

Dose is concentration dependent

68
Q

Sulfonamide MOA?

A

Inhibit folic acid synthesis

69
Q

Sulfonamide agents?

A

Bactrim (TMP/SMX AKA Trimethoprim/Sulfamethoxazole)

70
Q

Sulfonamide spectrum?

A

Gram positive and gram negatives (NO Pseudomonas), increasing resistance

71
Q

Sulfonamide uses?

A

Respiratory tract infections, UTI, PCP, community-acquired MRSA

72
Q

Sulfonamide AEs?

A

GI, hypersensitivity, photosensitivity, maculopapular rash, QT prolongation, “yellow babies” (AKA newborn kenicterus, avoid use in pregnancy near term), myelosuppression, hemolytic anemia (avoid if G6PD)

73
Q

Sulfonamide drug-drug interactions?

A

Warfarin, sulfonylureas, caution with ACEi and ARBS (hyperkalemia)

74
Q

General antibiotic classes to be cautious with QT prolongation?

A

FQs, macrolides, and sulfas

75
Q

Metronidazole (Flagyl) MOA?

A

Inhibits protein synthesis by interacting with DNA

76
Q

Metronidazole ROA?

A

PO and IV

77
Q

Metronidazole spectrum?

A

Anaerobes (Bacteroides, C diff - best below diaphragm, parasites, H pylori)

78
Q

Metronidazole use?

A

Trichomonas, C difficile, H pylori

Good atypical coverage

79
Q

Metronidazole AEs?

A

EtOH intolerance (flushing, tachycardia, n/v, hypotension, dyspnea)

Interactions with warfarin

80
Q

Lincosamide MOA?

A

Inhibits protein synthesis

81
Q

Lincosamide agent?

A

Clindamycin

82
Q

Clindamycin spectrum?

A

Gram positive and anaerobes (above diaphragm)

83
Q

Clindamycin use?

A

MRSA, PCN allergic patients, acne, hidradenitis (topical)

84
Q

Clindamycin AEs?

A

Bad taste (kids hate), esophageal irritation, hepatotoxicity, pseudomonas colitis (C.diff)

85
Q

Nitrofurans agents?

A

PO nitrofurantoin (Macrobid)

86
Q

Nitrofurantoin spectrum?

A

Covers gram positive and gram negative
Most urinary pathogens (enterococci, gram negative bacilli)

87
Q

Nitrofurantoin AEs?

A

Pulmonary fibrosis with long term use, hemolytic anemia, kidney stones

Renal excretion

88
Q

Lipo/glycopeptide MOA?

A

Inhibits cell wall synthesis

89
Q

Lipo/glycopeptide agents?

A

Vancomycin, daptomycin, telacancin, oritavancin, dalbacancin

“Heavy hitter”

90
Q

Vancomycin spectrum?

A

MRSA coverage
PO: C diff
IV: endocarditis, staph inf, empiric therapy when MRSA suspected

91
Q

Vancomycin use?

A

Therapy of choice for serious gram positive staphylococcal infections when the penicillins and cephalosporins cannot be used

Also covers other gram-positive cocci and bacteria and gram-negative cocci

92
Q

Vancomycin AEs?

A

Infusion reactions, red man syndrome, nephrotoxocity, drug induced immune thrombocytopenia, neutropenia, pancytopenia, ototoxicity

93
Q

Oxazolinone MOA?

A

Inhibits protein synthisis, suppress bacterial production of toxins

94
Q

Oxazolinone agents?

A

Linezolid, Tedizolid

95
Q

Oxazolinone spectrum?

A

Gram positive organisms

“Heavy hitters”

96
Q

Oxazolinone use?

A

Linezolid: PNA, skin and soft tissue infections, vancomycin-resistant enterococcus; MRSA coverage

97
Q

Oxazolinone AEs?

A

Myelosuppression (duration dependent), peripheral/optic neruopathy (duration and dose dependent), hypoglycemia, hepatotoxicity, lactic acidosis, serotonin syndrome with linezolid

98
Q

Linezolid monitoring?

A

Yes: weekly CBC, BMP, LFT if taking > 7 days; neuro and ophtho assessment if taking > 28 days

99
Q

MRSA treatments?

A

PO: Linezolid and tedizolid

IV: Vancomycin

Community Acquired: SMX-TMP, clindamycin, tetracyclines

Hospital Acquired: Vancomycin (Drug of choice), linezolid, daptomycin, Synercid

100
Q

Vancomycin pearls?

A

IV best for MRSA

PO best for C. diff

AEs: Red man’s syndrome (increased histamine), ototoxicity, nephrotoxicity

Pretreat with diphenhydramine and slower infusion rate to prevent Red Man’s Syndrome (not a true allergy)

101
Q

What antibiotics have MRSA coverage?

A

Doxycycline, ceftaroline (5th gen), clindamycin (only some coverage), delafloxacin, bactrim, vancomycin, linezolid and tedizolid

102
Q

What antibiotics have Pseudomonas coverage?

A

Cefepime (4th gen) , cefiderocol (5th gen), FQs, ceftazidime, pip-tazo, tobramycin (best for pseudomonas), gentamycin, aztreonam, imipenem (must use with cilstatin), metropenem

Also: polymyxin B (eye drops); 5th gen cephalosporins are antipseudomonal

103
Q

What antibiotics are renally excreted?

A

Beta lactams (mostly)

Glycopeptides (Vancomycin)

Aminoglycosides

Nitrofurans

104
Q

What antibiotics have a mixed renal/hepatic excretion?

A

Fluoroquinolones

Tetracyclines

105
Q

What antibiotics are hepatically excreted?

A

Ceftriaxone

Macrolides

Metronidazole

Nafcillin (only PCN not renally excreted)

106
Q

What antibiotics INCREASE INR?

A

Macrolides (clarithromycin)

FQs (ciprofloxacin)

Metronidazole (2-4x increase, esp. older adults)

TMP/SMX (2-4x increase, esp. older adults)

107
Q

What antibiotics DECREASE INR?

A

Rifampin

108
Q

Category B antibiotics?

A

Most Beta Lactams

Clindamycin

Azithromycin, Erythromycin

Metronidazole (avoid in 1st trimester)

PO Vancomycin

Nitrofurantoin (avoid at term)

109
Q

Category C antibiotics?

A

Clarithromycin

Fluoroquinolones

TMP/SMX (avoid 1st and 3rd trimesters)

IV Vancomycin

110
Q

Category D antibiotics?

A

Aminoglycosides

Tetracyclines