Antimicrobial Therapy Flashcards

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1
Q

Antimicrobial therapy

folic acid synthesis

A
  • Sulfonamides
  • Trimethoprim
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2
Q

Antimicrobial therapy

DNA Topoisomerases

A
  • Fluoroquinolones
  • Quinolone
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3
Q

Antimicrobial therapy

damages DNA

A

Metronidazole

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4
Q

Antimicrobial therapy

mRNA synthesis

A

Rifampin

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5
Q

Antimicrobial therapy

protein synthesis (50S)

A
  • Chloramphenicol
  • Clindamycin
  • Linezolid
  • Macrolides
  • Streptogramins
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6
Q

Antimicrobial therapy

protein synthesis (30S)

A
  • Aminoglycosides
  • Tetracyclines
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7
Q

Antimicrobial therapy

cell wall synthesis (peptidoglycan cross linking)

A
  • penicillinase-sensitive penicillins
  • penicillinase-resistant penicillins
  • antipseudomonals
  • cephalosporins
  • carbapenems
  • monobactams
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8
Q

Antimicrobial therapy

cell wall synthesis (peptidoglycan synthesis)

A

Glycopeptides

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9
Q

Penicillin G, V

administration

A
  • prototype ß-lactam antibiotics
  • penicillin G - IV & IM
  • penicillin V - oral
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10
Q

Penicillin G, V

mechanism

A
  • bind PBPs (transpeptidases)
  • block transpeptidase cross-linking of peptidoglycan
  • activate autolytic enzymes
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11
Q

Penicillin G, V

clinical use

penicillinase

A
  • gram (+) organisms
    • S. pneumoniae, S. pyogenes, Actinomyces
  • N. meningitidis, T. pallidum
  • bactericidal: gram (+) cocci, gram (+) rods, gram (-) cocci, spirochetes
  • penicillinase sensitive
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12
Q

Penicillin G, V

toxicity

A
  • hypersensitivity rxns
  • hemolytic anemia
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13
Q

Penicillin G, V

resistance

A

penicillinase in bacteria cleaves ß-lactam ring

type of ß-lactamase

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14
Q

Ampicillin, amoxicillin

mechanism

A
  • same as penicillin
  • wider spectrum
  • penicillinase sensitive
  • combine w/ clavulanic acid to protect against ß-lactamase
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15
Q

Ampicillin, amoxicillin

clinical use

A

HELPSS kill enterococci

  • extended-spectrum penicillin
  • Haemophilus influenzae
  • E. coli
  • Listeria monocytogenes
  • Proteus mirabilis
  • Salmonella
  • Shigella
  • enterococci
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16
Q

Ampicillin, amoxicillin

toxicity

A
  • hypersensitivity rxns
  • rash
  • psuedomembranous colitis
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17
Q

Ampicillin, amoxicillin

resistance

A
  • penicillinase in bacteria cleaves ß-lactam ring
  • ß-lactamase
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18
Q

Oxacillin, nafcillin, dicloxacillin

mechanism

A
  • same as penicillin
  • narrow spectrum
  • **penicillinase resistant **
    • bulky R group
    • blocks access of ß-lactamase to ß-lactam ring
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19
Q

Oxacillin, nafcillin, dicloxacillin

clinical use

A

S. aureus (except MRSA)

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20
Q

Oxacillin, nafcillin, dicloxacillin

toxicity

A
  • hypersensitivity rxns
  • interstitial nephritis
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21
Q

Ticarcillin, piperacillin

mechanism

A
  • same as penicillin
  • extended spectrum
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22
Q

Ticarcillin, piperacillin

clinical use

A
  • Pseudomonas spp.
  • gram-negative rods
  • susceptible to penicillinase
  • **use w/ ß-lactamase inhibitors **
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23
Q

Ticarcillin, piperacillin

toxicity

A

hypersensitivity rxns

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24
Q

ß-lactamase inhibitors

A

CAST

  • Clavulanic Acid
  • Sulbactam
  • Tazobactam
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25
Q

Cephalosporins

mechanism

A
  • ß-lactams
  • **inhibit cell wall synthesis **
  • less susceptible to penicillinases
  • bactericidal
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26
Q

1st generation cephalosporins

A

**cefazolin, cephalexin **

  • gram (+) cocci
  • PEcK
    • Proteus mirabilis
    • E. coli
    • Klebsiella
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27
Q

_______ used prior to surgery to prevent S. aureus wound infections.

A

Cefazolin

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28
Q

2nd generation cephalosporins

A

**cefoxitin, cefaclor, cefuroxime **

  • gram (+) cocci
  • HEN PEcKS
    • Haemophilus influenzae
    • Enterobacter aerogenes
    • Neisseria spp.
    • Proteus mirabilis
    • E. coli
    • Klebsiella pneumoniae
    • Serratia marcescens
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29
Q

3rd generation cephalosporins

A

**ceftriaxone, cefotaxime, ceftazidime **

  • serious gram (-) infections resistant to other ß-lactams
  • Ceftriaxone - meningitis & gonorrhea
  • Ceftazidime - Psuedomonas
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30
Q

4th generation cephalosporins

A

cefepime

  • increased activity against Pseudomonas & gram (+) organisms
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31
Q

5th generation cephalosporins

A

ceftaroline

  • broad gram (+) & gram (-) organism coverage
  • MRSA, not Pseudomonas
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32
Q

Cephalosporins

toxicity

A
  • hypersensitivity rxns
  • vitamin K deficiency
  • low cross-reactivity w/ penicillins
  • increased nephrotoxicity of aminoglycosides
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33
Q

Aztreonam

mechanism

A
  • monobactam
  • resistant to ß-lactamases
  • prevents peptidoglycan cross-linking
    • binds PBP
  • synergistic w/ aminoglycosides
  • no cross-allergy w/ penicillins
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34
Q

Aztreonam

clinical use

A
  • gram (-) rods only
  • penicillin-allergic patients
  • patients w/ renal insufficiency who can’t tolerate aminoglycosides
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35
Q

Aztreonam toxicity

A
  • usually non-toxic
  • occasional GI upset
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36
Q

Carbapenems

A
  • Imipenem
  • Meropenem
  • Ertapenem
  • Doripenem
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37
Q

Carbapenems

mechanism

A

Imipenem

  • broad-spectrum, ß-lactamase resistant
  • admin w/ cilastatin
    • inhibitor of renal dehydropeptidase I
    • decreased inactivation of drug in renal tubules
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38
Q

Carbapenems

clinical use

A
  • gram (+) cocci, gram (-) rods, anaerobes
  • wide spectrum
  • **life-threatening infections or when other drugs have failed **
  • Meropenam has decreased risk of seizures
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39
Q

Carbapenems

toxicity

A
  • GI distress
  • skin rash
  • CNS toxicity (seizures)
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40
Q

Vancomycin

mechanism

A
  • inhibits cell wall peptidoglycan formation
  • binds D-ala-D-ala
  • bactericidal
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41
Q

Vancomycin

clinical use

A
  • gram (+) only
  • serious, multidrug-resistant organisms
  • MRSA, enterococci, C. difficile
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42
Q

Vancomycin

toxicity

A

NOT trouble-free

  • Nephrotoxicity
  • Ototoxicity
  • Thrombophlebitis
  • diffuse flushing
  • red man syndrome
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43
Q

Vancomycin

resistance

A
  • aa modification of D-ala-D-ala to D-ala-D-lac
44
Q

Protein synthesis inhibitors

  • 30S inhibitors
  • 50S inhibitors
A

Buy AT 30, CCEL (sell) at 50

  • 30S inhibitors
    • Aminoglycosides
    • Tetracyclines
  • 50S inhibitors
    • Chloramphenicol, Clindamycin
    • Erythromycin (macrolides)
    • Linezolid
45
Q

Aminoglycosides

A

GNATS

  • Gentamicin
  • Neomycin
  • Amikacin
  • Tobramycin
  • Streptomycin
46
Q

Aminoglycosides

mechanism

A
  • bactericidal
  • **inhibits formation of initiation complex **
  • misreading of mRNA
  • blocks translocation
  • requires O2 (aerobes)
47
Q

Aminoglycosides

clinical use

A
  • severe gram (-) rod infections
  • synergistic w/ ß-lactam antibiotics
48
Q

________ for bowel surgery.

A

Neomycin

49
Q

Aminoglycosides

toxicity

A

NNOT

  • Nephrotoxicity
  • Neuromuscular blockade
  • Ototoxicity
  • Teratogen
50
Q

Aminoglycosides

resistance

A
  • bacterial transferase enzymes inactivate drug
    • acetylation
    • phosphorylation
    • adenylation
51
Q

Tetracyclines

A
  • Tetracycline
  • Doxycycline
  • Minocycline
52
Q

Tetracyclines

mechanism

A
  • bacteriostatic
  • binds 30S & prevents attachment of aminoacyl tRNA
  • limited CNS penetration
53
Q

________ is fecally eliminated & can be used in patients w/ renal failure.

A

Doxycycline

54
Q

Do not take tetracyclines w/ ______, _____, or ____-containing preparations b/c divalent cations inhibit its absorption in the gut.

A
  • milk (Ca2+)
  • antacids (Ca2+, Mg2+)
  • iron
55
Q

Tetracyclines

clinical use

A
  • Borrelia burgdorferi
  • M. pneumoniae
  • Rickettsia & Chlamydia (intracellular)
  • treats acne
56
Q

Tetracyclines

toxicity

A
  • GI distress
  • _discoloration of teeth & inhibition of bone growth _
    • children
  • photosensitivity
  • contraindicated in pregnancy
57
Q

Tetracyclines

resistance

A

decreased uptake or increased efflux out of bacterial cells by _plasmid-encoded transport pumps _

58
Q

Macrolides

A
  • Azithromycin
  • Clarithromycin
  • Erythromycin
59
Q

Macrolides

mechanism

A
  • inhibit protein synthesis
  • **block translocation **
  • bind 23S rRNA of 50S ribosomal subunit
  • bacteriostatic
60
Q

Macrolides

clinical use

A
  • atypical pneumonias
    • Mycoplasma
    • Chlamydia
    • Legionella
  • STDs
    • Chlamydia
  • gram (+) cocci
    • Strep in patients allergic to penicillin
61
Q

Macrolides

toxicity

A

MACRO

  • GI Motility issues
  • Arrhythmia (prolonged QT)
  • acute Cholestatic hepatitis
  • Rash
  • eOsinophilia
  • Increases serum conc of theophyllines, oral anticoagulants
62
Q

Macrolides

resistance

A

methylation of 23S rRNA-binding site

63
Q

Chloramphenicol

mechanism

A

blocks peptidyltransferase at 50S ribosomal subunit

64
Q

Chloramphenicol

clinical use

A
  • meningitis
    • Haemophilus influenzae
    • Neisseria meningitidis
    • Streptococcus pneumoniae
  • rocky mountain spotted fever
    • Rickettsia rickettsii
  • limited use due to toxicity (but low cost)
65
Q

Chloramphenicol

toxicity

A
  • anemia (dose dependent)
  • aplastic anemia (dose independent)
  • **gray baby syndrome **
    • premature infants
    • lack liver UDP-glucuronyl transferase
66
Q

Chloramphenicol

resistance

A

plasmid-encoded acetyltransferase inactivates the drug

67
Q

Clindamycin

mechanism

A

blocks peptide transfer (translocation) at 50S ribosomal subunit

68
Q

Clindamycin

clinical use

A
  • anaerobic infections (Bacteroides, Clostridium perfringens) in…
    • aspiration pneumonia
    • lung abscesses
    • oral infections
  • invasive group A strep infection
69
Q

______ treats anaerobes above the diaphragm.

______ treats anaerobes below the diaphragm.

A

Clindamycin

Metronidazole

70
Q

Clindamycin

toxicity

A
  • Pseudomembranous colitis (C. diff overgrowth)
  • fever
  • diarrhea
71
Q

Sulfonamides

A
  • sulfamethoxazole (SMX)
  • sulfisoxazole
  • sulfadiazine
72
Q

Sulfonamides

mechanism

A
  • inhibit folate synthesis
  • PABA antimetabolites inhibit dihydropteroate synthase
  • bacteriostatic
73
Q

Sulfonamides

clinical use

A
  • gram (+)
  • gram (-)
  • Nocardia
  • Chlamydia
  • triple sulfas or SMX for simple UTI
74
Q

Sulfonamides

toxicity

A
  • hypersensitivity rxns
  • hemolysis if G6PD deficient
  • nephrotoxicity (tubulointerstitial nephritis)
  • photosensitivity
  • kernicterus in infants
  • displace other drugs from albumin (warfarin)
75
Q

Sulfonamides

resistance

A
  • altered enzyme (bacterial dihydropteroate synthase)
  • decreased uptake
  • increased PABA synthesis
76
Q

Trimethoprim

mechanism

A

inhibits bacterial DHFR

bacteriostatic

77
Q

Trimethoprim

clinical use

A
  • combination w/ sulfonamides (TMP-SMX)
  • sequential blockade of folate synthesis
  • combination used for UTIs, Shigella, Salmonella, PCP pneumonia treatment & prophylaxis, toxoplasmosis prophylaxis
78
Q

Trimethoprim

toxicity

A
  • megaloblastic anemia
  • leukopenia
  • granulocytopenia
79
Q

Fluoroquinolones

A
  • ciprofloxacin
  • norfloxacin
  • levofloxacin
  • ofloxacin
  • sparfloxacin
  • moxifloxacin
  • gemifloxacin
  • enoxacin
  • nalidixic acid (quinolone)
80
Q

Fluoroquinolones

mechanism

A
  • inhibit DNA gyrase (topoisomerase II) & topoisomerase IV
  • bactericidal must NOT be taken w/ antiacids
81
Q

Fluoroquinolones

clinical use

A
  • gram (-) rods of urinary & GI tracts
    • includes Pseudomonas
  • Neisseria
  • some gram (+)
82
Q

Fluoroquinolones

toxicity

A
  • GI upset
  • superinfections
  • skin rashes
  • headache
  • dizziness
  • less common: tendonitis, tendon rupture, leg cramps, myalgias
  • contraindicated in pregnant women, nursing mothers, children <18 YO –> possible damage to cartilage
  • prolonged QT interval
  • tendon rupture in >60 YO & patients taking prednisone
83
Q

Fluoroquinolones

resistance

A
  • chromosome-encoded mutation in DNA gyrase
  • plasmid-mediated resistance
  • efflux pumps
84
Q

Metronidazole

mechanism

A
  • free radical toxic metabolites in bacterial cell that damage DNA
  • bactericidal
  • antiprotozoal
85
Q

Metronidazole

clinical use

A

**GET GAP **

  • Giardia
  • Entamoeba
  • Trichomonas
  • Gardnerella vaginalis
  • Anaerobes (Bacteroides, C. difficile)
  • H. Pylori (triple therapy)
    • metronidazole + PPI + clarithromycin
86
Q

Metronidazole

toxicity

A
  • disulfiram-like rxn w/ alcohol
    • severe flushing
    • tachycardia
    • hypotension
  • headache
  • metallic taste
87
Q

Antimycobacterial drugs

  • M. tuberculosis
  • M. avium-intracellulare
  • M. leprae
A
  • M. tuberculosis
    • Prophylaxis: Isoniazid
    • Treatment: RIPE
      • Rifampin
      • Isoniazid
      • Pyrazinamide
      • Ethambutol
  • M. avium-intracellulare
    • Prophylaxis: azithromycin, rifabutin
    • Treatment: azithromycin/clarithromycin + ethambutol
  • M. leprae
    • Prophylaxis: N/A
    • Treatment: dapson & rifampin (T); + clofazimine (L)
88
Q

Isoniazid

mechanism

A
  • decreases synthesis of mycolic acids
  • bacterial catalase-peroxidase needed to convert to active metabolite
89
Q

Isoniazid

toxicity

A

INH Injures Neurons & Hepatocytes

  • neurotoxicity
  • hepatotoxicity
  • pyridoxine (vit B6) can prevent neurotoxicity, lupus
90
Q

Rifamycins

A
  • Rifampin
  • Rifabutin
91
Q

4 R’s of Rifampin

A

Rifampin ramps up CYP450, but rifabutin does not

  • RNA polymerase inhibitor
  • Ramps up microsomal CYP450
  • Red/orange body fluids
  • Rapid resistance if used alone
92
Q

Rifamycins

_____ favored over _____ in patients w/ HIV infection due to less CYP450 stimulation.

A

rifabutin

rifampin

93
Q

Pyrazinamide

mechanism

A
  • uncertain
  • **thought to acidify intracellular environment **
  • conversion to pyrazinoic acid
  • effective in acidic pH of phagolysosomes (TB engulfed by macrophages)
94
Q

Pyrazinamide

clinical use

toxicity

A
  • Mycobacterium tuberculosis
  • Hyperuricemia, hepatotoxicity
95
Q

Ethambutol

mechanism

A

decreases carb polymerization of mycobacterium cell wall by blocking arabinosyltransferase

96
Q

Ethambutol

clinical use

toxicity

A
  • Mycobacterium tuberculosis
  • Optic neuropathy (red-green color blindness)
97
Q

antimicrobial prophylaxis

endocarditis w/ surgical or dental procedures

A

penicillins

98
Q

antimicrobial prophylaxis

gonorrhea

A

ceftriaxone

99
Q

antimicrobial prophylaxis

history of recurrent UTIs

A

TMP-SMX

100
Q

antimicrobial prophylaxis

meningococcal infection

A

ciprofloxacin

rifampin (children)

101
Q

antimicrobial prophylaxis

pregnant woman carrying group B strep

A

ampicillin

102
Q

antimicrobial prophylaxis

prevention of gonococcal or chlamydial conjunctivitis of the newborn

A

erythromycin ointment

103
Q

antimicrobial prophylaxis

prevention of postsurgical infection due to S. aureus

A

cefazolin

104
Q

antimicrobial prophylaxis

prophylaxis of strep pharyngitis in child w/ prior rheumatic fever

A

oral penicillin

105
Q

antimicrobial prophylaxis

syphilis

A

benzathine penicillin G