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Step 1 Pharm > Anti Microbials (1) > Flashcards

Anti Microbials (1) Flashcards

1
Q

Overview of antimicrobial action

A

review chart

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2
Q

What are the 3 Mechanism of Penicillins?

How do bacteria resisit it?

A
  1. Bind penicillin-binding proteins (transpeptidases).
  2. Block transpeptidase cross-linking of peptidoglycan in cell wall.
  3. Activate autolytic enzymes.

Penicillinase in bacteria (a type of β-lactamase) cleaves β-lactam ring.

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3
Q

Mostly used for gram-positive organisms (S. pneumoniae, S. pyogenes, Actinomyces). Also used for gram-negative cocci (mainly N. meningitidis) and spirochetes (namely T. pallidum).

Bactericidal for gram-positive cocci, gram-positive rods, gram-negative cocci, and spirochetes.

A

Penicillin

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4
Q

What is the mechanism of teh drug we would tx pt with syphillus with?

A

Tx with Pen G

Bind penicillin-binding proteins (transpeptidases).
Block transpeptidase cross-linking of peptidoglycan in cell wall.

Activate autolytic enzymes.

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5
Q

What toxic side effects are seen with Penicillin?

A

Hypersensitivity reactions,

hemolytic anemia.

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6
Q

What is the Mechanism of aminopenicillins?

What drugs are aminopenicillins?

Which one has the best oral availability?

A

AMinoPenicillins are AMPed-up penicillin.: Same as penicillin. Wider spectrum; penicillinase sensitive. Also combine with clavulanic acid to protect against destruction by β-lactamase.

Amoxicillin, ampicillin are both aminopenicillins

AmOxicillin has greater Oral bioavailability than ampicillin.

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7
Q

PNeumonic for Amoxicillin use:

ampicillin/amoxicillin HHELPSS kill enterococci.

A

H. influenza and H.pylori

E.coli

Listeria

Proteus

Salmonella

shigella

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8
Q

What mechnism of resistance is seen with aminopenicillins?

What toxicity is assoicated with them?

A

Penicillinase in bacteria (a type of β-lactamase) cleaves β-lactam ring.

Hypersensitivity reactions; rash; pseudomembranous colitis.

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9
Q

Same as penicillin. Narrow spectrum; penicillinase resistant because bulky R group blocks access of β-lactamase to β-lactam ring.

A

Dicloxacillin, nafcillin, oxacillin (penicillinase-resistant penicillins):

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10
Q

What drug can we use to treat Staph Aureus (but not MRSA d/t altered penicillin binding proteins target sites)

What is it’s mechanism?

A

Use Nafcillin “ Use naf for staph’

penicillinase-resistant penicillins to treat Staph Aureus

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11
Q

When using a penicillinase-resistant penicillin (specifically Nafcillin) what do we use it for and when side effects can we see?

A

Nafcillin for Staph Aureus

Sides: Hypersensitivity rxns and Interstitial nephritis

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12
Q

Drug used to treate Pseudomonas spp. and gram-negative rods;

A

Piperacillin, ticarcillin (antipseudomonals)

use with β-lactamase inhibitors.

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13
Q

When would you use Piperacillin or ticaracillin (antipseudomonals)

A

Duh, Pseudomonas

MOA:

Bind penicillin-binding proteins (transpeptidases).
Block transpeptidase cross-linking of peptidoglycan in cell wall.

Activate autolytic enzymes.

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14
Q

What drugs are B-lactamase inhibitors and whenw would we use them?

A

Include Clavulanic Acid, Sulbactam, Tazobactam.

Often a_dded to penicillin a_ntibiotics to protect the antibiotic from destruction by β-lactamase (penicillinase).

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15
Q

What is the general mechanism of Cephalosporins?

What bugs are NOT covered by cephalosporins?

A

β-lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinases. Bactericidal.

Organisms typically not covered by cephalosporins are LAME:

Listeria, Atypicals (Chlamydia, Mycoplasma), MRSA, and Enterococci.

Exception: ceftaroline covers MRSA.

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16
Q

What drugs are the 1st gen Cephalosporins?

What is their use?

A

1st generation (cefazolin, cephalexin)—

Coverage: gram- positive cocci,

PEcK: Proteus mirabilis, E. coli, Klebsiella pneumoniae.

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

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17
Q

What drug can we use to treat the “PEcK” or

Proteus miribalis, E.Coli, Klebsiella pneumonaie

A

Use 1st gen cephalosporins

Cefazolin and Cephalexin

18
Q

Drugs used to treat —gram-positive cocci, HEN PEcKS

Haemophilus influenzae, Enterobacter aerogenes, Neisseria spp., Proteus mirabilis, E. coli, Klebsiella pneumoniae, Serratia marcescens.

A

2nd generation: cefoxitin, cefaclor, cefuroxime

19
Q

What are my second gen Cephalosporins?

What bugs do they treat?

A

Cefoxitin, Cefaclor,Cefuroxime

HEN PEcKS:

H. influenza, Enterobacter, Neisseria, Proteus, E.Coli, Klebsiella, Serratia

20
Q

What does HEN PEcKS stand for?

What drugs treat these bugs?

What is their mechanism?

A

H. Influenza, Enterobacter, Neisseria, Proteus, E. Coli, Klebsiella, Serratia

Second gen cephalosporins: Cefoxotin, Cefuroxime, Cefaclor

β-lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinases. Bactericida

21
Q

What is the drug of choice to three Gonorrhea and meningitis?

What is it’s mechanism of action?

A

Ceftriaxone: it’s a 3rd gen cephalosporin

22
Q

What are my 3rd generation cephalosporins?

What is their coverage?

A

= Ceftriaxone, Cefoxatime, Ceftazidime

Used for _serious gram negative infections r_esistant to other B-lactams

Ceftriaxone—meningitis, gonorrhea, disseminated Lyme disease.

Ceftazidime—Pseudomonas.

23
Q

What drug can we use to treat a pseudomonas infection?

A

Ceftazidine: 3rd gen cephalosporin

24
Q

What is Cefipime and when would it be a beneficial drug?

A

4th generation (cefepime)—gram-negative

organisms, with?activity against Pseudomonas

and gram-positive organisms.

25
Q

What sensitivities do we need to worry about with cephalosporins?

A

Hypersensitivity reactions, autoimmune hemolytic anemia, disulfiram-like reaction, vitamin K deficiency. Exhibit cross-reactivity with penicillins.?

Incerease nephrotoxicity of aminoglycosides.

26
Q

What happens when we prescribe an aminoglycoside as well as a cephalosporin?

A

Increases chances for nephrotoxicity

27
Q

What drug causes this side effect:

Hypersensitivity reactions, autoimmune hemolytic anemia, disulfiram-like reaction, vitamin K deficiency. Exhibit cross-reactivity with penicillins.

A

Cephalosporins

28
Q

________is a broad-spectrum, β-lactamase– resistant carbapenem.

Always administered with cilastatin (inhibitor of renal dehydropeptidase I) to decrease ?inactivation of drug in renal tubules.

A

Imipenem

“With imipenem, “the kill is lastin’ with cilastatin.”

29
Q

What is the side effect profile like for carbapenems?

A

GI distress, skin rash, and CNS toxicity (seizures) at high plasma levels.

30
Q

Inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors.

Bactericidal.

Not susceptible to β-lactamases.

A

Vancomycin

31
Q

When would we prescribe vancomycin?

A

Gram-positive bugs only—serious, multidrug-resistant organisms, including

MRSA, S. epidermidis, sensitive Enteroccocus species, and Clostridium difficile (oral dose for pseudomembranous colitis).

32
Q

What drug can we prescribe for the following diseases?

Gram-positive bugs only—serious, multidrug-resistant organisms, including MRSA, S. epidermidis, sensitive Enteroccocus species, and Clostridium difficile (oral dose for pseudomembranous colitis).

A

Vancomycin

33
Q

Well tolerated in general—but NOT trouble free.

Nephrotoxicity, Ototoxicity, Thrombophlebitis, diffuse flushing—red man syndrome (can largely prevent by pretreatment with antihistamines and slow infusion rate)

A

VAncomycin

34
Q

How do bugs resist Vancomycin?

A

Occurs in bacteria via amino acid modification of D-ala D-ala to D-ala D-lac.

“Pay back 2 D-alas (dollars) for vandalizing (vancomycin).”

35
Q

What antimicrobials target the 30S of bacteria ribosome?

are they bacteriocidal or static?

A

30S:

Aminoglycosides = bacteriacidal

Tetracyclines =bacteriostatic

36
Q

What antimicrobials are will inhibit the 50S subunit?

A

Chloramphenicol and Clindamycin = bacteriostatic

Erythromycin = macrolide and static

Linezolid

37
Q

What are teh aminioglycosides?

What is the MOA?

What toxicity do we worry about?

A

Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin

Irreversible inhibition of initiation complex through binding of the 30S subunit

Can cause misreading of mRNA

Blocks translocation but NEEDS O2 for uptake thus no good for anaerobes.

*Toxicity: Nephrotoxicity, Neuromuscular blockade, Ototoxicity, Teratogenic

38
Q

The combination of gentamicin with Furosomide would have what type of side effect?

A

aminoglycoside + loop = bad news!

Serious Ototoxicity

39
Q

When would we prescribe aminoglycosides to a pt?

A

Severe gram-negative rod infections.

Synergistic with β-lactam antibiotics.

Neomycin for bowel surgery.

40
Q

What is the mechanism of resistance of bugs against aminoglycosides?

A

Bacterial transferase enzymes inactivate the drug by acetylation, phosphorylation, or adenylation.

Step 1 Pharm (15 decks)

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