Antimicrobials 1 Flashcards

1
Q

Name the primary class of drugs that affect cell wall synthesis.

A

Beta lactams

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2
Q

What are the four subclasses of beta lactam antibiotics?

A

Penicillins (4 categories)
Cephalosporins (5 generations)
Carbapenems
Monobactams

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3
Q

To be effective, what four criteria must be met for beta lactams to be effective?

A
  1. evade bacterial defenses 2. penetrate outer cell layers to inner cytoplasmic membrane 3. keep the beta lactam ring intact 4. bind to transpeptidase
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4
Q

What is the ultimate method of action of beta-lactams?

A

They bind to active site of the PBP enzyme to prevent transpeptidation (terminal step in cell wall synthesis)

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5
Q

What is the only true naturally occurring penicillin?

A

Penicillin G

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6
Q

What two antimicrobials are natural penicillins?

A

Pen G, Pen V (aka Pen VK)

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7
Q

What are natural penicillins effective against?

A

sensitive strains of Gram + cocci (Pen G also active against some gram - Neisseria and anaerobes)

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8
Q

Are Natural penicillins narrow or broad spectrum?

A

Narrow spectrum

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9
Q

What are two Aminopenicillin antimicrobials?

A

Ampicillin, Amoxicillin

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10
Q

Since activity is extended compared to natural penicillins, aminopenicillins are referred to as what?

A

Extended spectrum penicillins

better Gram negative coverage than natural penicillins

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11
Q

Aminopenicillins are administered with B-lactamase inhibitors such as? (3 names)

A

Clavulanate, Sulbactam, or Tazobactam

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12
Q

What is augmentin?

A

Amoxicillin + Clavulanate

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13
Q

Ampicillin should not be consumed with?

A

food, because the food binds to the drug and disables it

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14
Q

What are aminopenicillins effective against?

A

Sensitive Gram + and sensitive Gram - bacteria like H. flu, E. coli, Salmonella, Shigella

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15
Q

What is the drug of choice for standard prophylaxis for infective endocarditis?

A

Amoxicillin

if allergic, can take cephalexin, or non-B-lactams

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16
Q

What three things interact with Ampicillin activity?

A

Hydrocortison (inactivates ampicillin), Oral contraceptives (inactivates contraceptive), and Probenecid (slows clearance of ampicillin)

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17
Q

What four antimicrobials are Penicillinase-resistant Penicillins (PRPs)?

A

methicillin, nafcillin, oxacillin, and dicloxacillin

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18
Q

PRPs are effective against what?

A

staphylococci, streptococci

NOT enterococci, anaerobic bacteria, gram - cocci or rods

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19
Q

What two PRPs are normally acid stable (given PO) with a reduced risk of interstitial nephritis?

A

Oxacillin, Dicloxacillin

also undergo biliary excretion, not renal

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20
Q

What is the drug of choice for serious Staphylococcus aureus infections that are non-methicillin resistant (non-MRSA)?

A

Nafcillin

Naf for Staph

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21
Q

What does probenecid do that causes it to increase drug half-life and prolong clearance?

A

Probenecid inhibits organic anion transporters in the proximal tubule, causing the drug to remain in the blood.

22
Q

What three drugs aren’t effected by probenecid?

A

Nafcillin, oxacillin, dicloxacillin (¾ of penicillinase-resistant penicillins)

23
Q

Carboxypenicillins, ureidopenicillins, and monobactams are what kind of B-lactam?

A

Anti-pseudonomal penicillins

24
Q

How are anti-pseudonomal penicillins administered?

A
either intramuscular (IM) or intravenously (IV)
NOT perorally (PO)
25
Q

What kind of anti-pseudonomal penicillin are Indanyl carbenicillin and Ticarcillin?

A

Carboxypenicillins

26
Q

What must be administered with ticarcillin?

A

Clavulanate (two are put into one dose in America - drug called Timentin)

27
Q

What are anti-pseudonomal penicillins effective against?

A

Everything Pen G is effective against, plus Gram negative bacteria like Pseudonomas aerugenosa

28
Q

What is Piperacillin?

A
An Ureidopenicillin 
(also broadest spectrum Penicillin)
29
Q

Aztreonam is what?

A
A monobactam (an A-PP)
(and great for pts with IgE-mediated penicillin allergy)
30
Q

Anaphylactic reactions are more common when penicillin is administered __________?

A

Parenterally (other route than mouth/GI)

31
Q

Name three allergic reactions to penicillin/B-lactams.

A

Anaphylactic (immediate - IgE mediated), Accelerated onset (30’ - 48” after admin), Delayed onset (2+ days - 80-90% of rxs)

32
Q

What are some signs/symptoms of anaphylaxis?

A

headache; lightheadedness; swelling of tongue, nose and/or throat; low BP; flushed skin; SOB; stridor; swelling of conjunctiva; etc

33
Q

Large doses of Pen G may produce _____, confusion, twitching, ________, kidney failure, and _____.

A

lethargy, seizures, coma

34
Q

10% of people are allergic to what?

A

Penicillins, and probably cross sensitive to all other B-lactams, including cephalosporins

35
Q

What difference is there between the 5 generations of cephalosporins?

A

From gen 1 to 5, they increase in spectrum size and B-lactamase resistance. Moderate to broad.

36
Q

All cephalosporins are bacteri____.

A

bactericidal

37
Q

Which generation cephalosporin is active against MRSA?

A

Gen 5 (ceftaroline)

38
Q

Cefazolin is which gen cephalosporin?

A

1 (don’t penetrate CNS)

39
Q

Cefaclor, Cefoxitin, Cefuroxime are which gen cephalosporin?

A

2 (good activity against E. coli, H. flu, and Klebsiella)

40
Q

Cefoxitin is a ______ and is effective against mixed ________ infections, like peritonitis and pelvic inflammatory disease.

A

cephamycin, anaerobe

41
Q

What cephalosporin crosses the blood brain barrier?

A

Cefuroxime

42
Q

Cefotaxime, Ceftazidime, and Cefdinir are which gen cephalosporin?

A

3 (all of these penetrate CNS to treat meningitis)

43
Q

Which cephalosporin is the highest selling and used to treat strep throat?

A

Cefdinir

44
Q

Cefepime is which gen cephalosporin?

A

4 (good against Enterobacter, but poor against anaerobes)

45
Q

Ceftaroline is which gen cephalosporin?

A

5

46
Q

Ceftaroline is most commonly used to treat what three things?

A

MRSA, Pseudomonas and community-acquired pneumonia

47
Q

What antimicrobial has the broadest spectrum known to man?

A

Imipenem (except MRSA and mycoplasma are resistant)

48
Q

Imipenem is what class of B-lactam, and is always coadministered with _______?

A

Carbapenems, cilistatin (to prevent rapid renal clearance of drug)

49
Q

What are some non-B-lactam antibacterials that prevent cell wall synthesis?

A

Vancomycin (covers all Gram +), Bacitracin (covers multi drug resistant Gram - )

50
Q

Name two non-B-lactams that disrupt cell membranes.

A

Bacitracin, Daptomycin (active against MRSA and VRE)

51
Q

How does Daptomycin disrupt bacterial cell membranes?

A

It inserts into the membrane and comes together to form a pore that ions freely pass through

52
Q

What drug MUST be administered topically?

A

Bacitracin, because another route is high enough concentration to cause kidney damage