Antimicrobials Flashcards

1
Q

Sulfa drugs (like TMP/SMX) inhibit the production of which vital precursor of nucleotide synthesis?

A

Folic Acid

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2
Q

TMP/SMX (Trimethoprim/Sulfamethoxazole)

A
  • Inhibit folic acid synthesis.
  • Good gram +ve and -ve coverage.
  • Does not cover anaerobes reliably.
  • Generally considered to be cidal.
  • Used to treat UTI, bacterial diarrhea, and some pneumonias.
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3
Q

Which drugs interfere which the bacterial membrane?

A

Polymyxin and Daptomycin

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4
Q

Polymyxin

A
  • Bind and alters CM permeability.
  • Cidal
  • Type B is a topical mixture.
  • Type E is administered through IV or inhaled.
  • Effective against gram -ve, especially highly resistant -ve bacilli.
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5
Q

Daptomycin

A
  • Bind the CM and disrupts it.
  • Cidal
  • Effective against gram +ve cocci.
  • Used against highly resistant +ve strains (MRSA & VRE).
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6
Q

Which drugs affect the bacterial cell wall? {Beta Lactams}

A

Patient Centred Care May Vary

  • Penicillins
  • Cephalosporins
  • Carbapenems
  • Monobactams
  • Vancomycin
  • Bacitracin
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7
Q

Which cell wall antimicrobials are cidal?

A

All of the main classes are cidal.

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8
Q

Penicillins

A

Penicillin, Amoxicillin, Ampicillin, Piperacillin

  • All are cidal to bacteria which are dividing.
  • All have some gram +ve and -ve coverage.
  • Gram -ve coverage increases up the triangle.
  • Piperacillin will also cover pseudomonas.
  • The penicillins alone will not cover staphylococcus.
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9
Q

What two combinations of penicillins and beta lactamase inhibitors can be used to cover staphylococcus?

A

Amoxicillin + Clavulanate
Pipercillin + Tazobactam

Cloxacillin may also be used for staph/strep infections. However, it does not build on the coverage of the penicillin pyramid.

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10
Q

Cephalosporins

A
  • Cidal drugs which affect cell wall synthesis.
  • Good coverage of gram +ve with increasing gram -ve coverage as the generations increase.
  • Third and fourth generations are able to cross the blood brain barrier (BBB).
  • Third generation cephalosporins lose their staph coverage.
  • HENPEK
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11
Q

What does HENPEK stand for?

A
H: Haemophilus influenza
E: Enterobacter
N: Neiserria
P: Proteus 
E: Escherichia Coli
K: Klebsiella
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12
Q

What are two first generation cephalosporins? What are they used to treat?

A

Cefazolin (IV) and Cephalexin (po).

They are often used to treat skin and soft tissue infections. They may be used for uncomplicated RTI.

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13
Q

What are NOT covered by the cephalosporins?

A

Listeria, enterococcus, and coagulase negative staphylococci.

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14
Q

What are two second generation cephalosporins? What additional coverage do they offer?

A

Cefuroxime (IV), Cefprozil (po).
They cover more gram -ve including HEN.
(Haemophilus influenzae, Enterobacter, and Neiserria)

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15
Q

What are four third generation cephalosporins? What is something NOT covered by third generation?

A

Cefotaxime, Ceftriaxone, Ceftazidime*(IV), and Cefixime (po).
*Covers pseudomonas but has decreased gram -ve coverage.
Third generation cephalosporins can cross the BBB but will not cover staph and has decreased gram +ve coverage compared to first generation.

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16
Q

What are two fourth generation cephalosporins?

What is their coverage like?

A

Cefepime and Ceftobiprole (IV).
Similar gram +ve coverage to first generation and the gram -ve coverage of the third generation with pseudomonas coverage.

17
Q

Name a monobactam. Give some interesting facts about it.

A

Aztreonam.

  • Bactericidal
  • Only covers gram -ve.
  • No anaerobe coverage.
  • Beta lactamase resistant.
18
Q

What are the carbapenems? How is their dissemination throughout the body?

A

Imipenem and Meropenem (the gorillacilins).

  • Cover almost all bacteria which are pathogenic to humans.
  • Meropenem has less side effects than imipenem.
  • Bactericidal
  • Penetrate body tissues and fluid very well.
19
Q

Vancomycin

A
  • Not a beta lactam but grouped with them.
  • Bactericidal
  • Vancomycin is a glycopeptide.
  • Very narrow spectrum covering only some gram +ve bacteria.
  • Effective against streptococci, enterococci, and staphylococci aureus.
20
Q

Bacitracin

A
  • Only used as a topical agent.

- Good gram +ve coverage.

21
Q

Which drugs affect protein synthesis?

A

Clyde The Clinician Ate The Lousy Eggs

  • Chloramphenicol
  • Tigecycline
  • Clindamycin
  • Aminoglycosides (Gentamicin & Tobramycin)
  • Tetracycline / Doxycycline
  • Linezolid
  • Erythromycins {Macrolides} (Erythromycin, Azithromycin, and Clarithromycin)
22
Q

Which drugs, which affect protein synthesis, are bactericidal?

A

The aminoglycosides Gentamicin and Tobramycin.

23
Q

What three drugs are macrolides? What do macrolides cover? What are they especially useful for?

A

Erythromycin, Azithromycin, and Clarithromycin.
Macrolides cover chlamydia, mycoplasma, gram +ve, and gram -ve respiratory bacilli.
They are especially useful against RTI and predominantly cover gram -ve bacilli like pneumonia.

24
Q

Which protein synthesis drugs affect the 30S ribosome?

A

The aminoglycosides (Gentamicin and Tobramycin), tetracycline / doxycycline, and tigecycline.

25
Q

Clindamycin results in increased risk of?

A

Antibiotic associated diarrhea and C. difficile colitis.

26
Q

Linezolid is used to treat?

A

Highly resistant gram +ve bacteria. However, it is expensive and generally reserved for use as a last resort.

27
Q

What coverage do the aminoglycosides offer?

A

Gram -ve bacilli (GUT) bacteria, excluding anaerobes.

28
Q

What coverage do tetracycline / doxycycline and tigecycline provide?

A

Both gram -ve and gram +ve bacteria including chlamydia and mycoplasma.
Tigecycline has addition coverage of gram -ve and gram +ve while also working against anaerobes.

29
Q

What side effect is associated with tetracycline / doxycycline and tigecycline?

A

Deposits on the teeth of children. It should not be given to pregnant women or children under the age of 8.

30
Q

What is not covered by tetracycline / doxycycline and tigecycline?

A

Pseudomonas and Proteus

31
Q

Which drugs hinder metabolic pathways?

A

TMP-SMX (Trimethoprim/Sulfamethoxazole)

32
Q

What is clindamycin used for?

A

It covers gram +ve and some anaerobic gram -ve bacilli. It is used for oral and gynaecological infections.

33
Q

The side effects of chloramphenicol include?

A

Gray baby syndrome and aplastic anemia.

34
Q

Chloramphenicol

A
  • Inhibits almost all relevant bacteria including anaerobes.
  • Not typically used in Canada due to serious side effects. (Gray baby syndrome & aplastic anemia).
  • Cheap and widely used in the third world.
35
Q

When does metronidazole act, and what does it act on?

A

It must be converted to its active form by anaerobic bacteria or parasites. It is effective against anaerobes, some parasites, and C. difficile.

36
Q

What is generally used as a prophylaxis to Neisseria meningitidis?

A

Rifampin

37
Q

Rifampin

A
  • Used in combination with other drugs to treat mycobacterial infections
  • Has some gram +ve effect.
  • Prophylaxis for Neisseria meningitidis.
  • Inhibits DNA dependant RNApol.
38
Q

Recall the mechanisms of bacterial resistance.

A
  • Block the antibiotic.
  • Fake out the antibiotic via altered metabolism.
  • Chew the antibiotic up.
  • Pump the antibiotic out.
39
Q

Which drugs act on nucleic acid synthesis?

A

Quintessential Rising Metropolis

  • Quinolones (Ciprofloxacin, Levofloxacin, Moxifloxacin, Gemifloxacin)
  • Rifampin
  • Metronidazole