Anti-bacterials Flashcards

1
Q

True of the MOA of aminoglycosides

a. Used synergystically with B lactams
b. Irreversibly binds to 30s ribosome and inhibit protein synthesis
c. Reversibly binds to 30s ribosome and inhibit protein synthesis
d. Irreversibly binds to 50s ribosome

A

C; Tetracyclines bind reversibly to 30s ribosome

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2
Q

Most ototoxic agents EXCEPT

a. neomycin
b. kanamycin
c. amikacin
d. tobramycin
e. AOTA

A

D;

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3
Q

Most nephrotoxic agents EXCEPT

a. Neomycin
b. Tobramycin
c. Amikacin
d. Gentamycin
e. AOTA

A

C.

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4
Q

True of Gentamycin’s spectrum of activity
a. has activity against S. aureus, S. viridans
b. has activity against anaerobes
c. has activity against E. coli, Klebsiella, Proteus,
Enterobacter, Acitenobacter
d. has activity against P. aeruginosa

A

B.

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5
Q

Ototoxic effects of gentamicin will manifest as _________, __________

A

tinnitus, verstibular damage

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6
Q

Enumerate 3 ways of tetra/doxy/minocycline resistance

A
  1. Impaired influx/increased effllux via Tet(AE) in Gram -
  2. Ribosome protection by Gram +
  3. Enzyme inactivation
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7
Q

Tetracycline GI absorption is impaired by the following EXCEPT

a. food (except doxy/minocycline)
b. divalent cations
c. alkaline pH
d. acids

A

D

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8
Q

True of pharmacokinetics of tetracyclines EXCEPT

a. Penetrates BBB
b. Penetrates placenta
c. Should not be orally administered with milk, antacids, or ferrous sulfate
d. AOTA

A

A

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9
Q

Clinical uses of tetracyclines EXCEPT

a. Infections caused by rickettsiae
b. M. pneumonia infections
c. in combination regimens for H. pylori gastric ulcer
d. Gonorrhea

A

D; other uses: treatment of acne, exacerbations of bronchitis, community-acquired pneumonia, Lyme disease, relapsing fever, leptospirosis, nontuberculous mycobacterial infections

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10
Q

Antibacteria that binds to 50s subunit of the bacterial ribosome and inhibits peptide bond formation

A

Chloramphenicol

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11
Q

Resistance to Chloramphenicol is due to

A

chloramphenicol acetyltransferase

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12
Q

True of chloramphenicol pharmacokinetics EXCEPT

a. adjusted for renal failure but not for hepatic failure
b. widely distributed to all tissues and body fluids: CNS, placenta
c. Oral formulation yields higher blood concentrations
d. NOTA

A

A; must be adjusted for hepatic failure not renal failure

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13
Q

Antibacterial that binds to 50s subunit of the ribosomal RNA and prevents peptide chain elongation by blocking the polypeptide exit tunnel

A

Macrolides

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14
Q

What chemical structure relates macrolides together?

A

Macrocyclic lactone ring

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15
Q

Resistance of Macrolides are due to the ff. (give 3)

A
  1. reduced permeability of the cell membrane or active efflux
  2. Production of esterases that hydrolyze macrolides
  3. Modification of ribosomal binding site
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16
Q

Clinical uses of Macrolides EXCEPT

a. Drug of choice in corynebacterial infections (diphtheria, corynebacterial sepsis, erythrasma)
b. Chlamydial infections
c. community-acquired pneumonia
d. Meningitis

A

D

17
Q

Adverse reactions of Macrolides EXCEPT

a. GI intolerance
b. Hepatitis
c. Inhibit CYP450 in liver
d. Taste Perversion
e. NOTA

A

E.

18
Q

What is the drug of choice in corynebacterial infections?

A

Macrolides

19
Q

True about Clarithromycin EXCEPT

a. improved acid stability and oral absorption compared with erythromycin
b. more active against M. avium complex
c. does not require adjustment with renal failure
d. similar interactions with erythromycin

A

C

20
Q

Among the macrolides, which does not inactivate CYP450?

A

Azithromycin

21
Q

What is the MOA of clindamycin?

A

inhibits protein synthesis by interfering with formation of initiation complexes and with aminoacyl translocation reactions

22
Q

Binding site of clindamycin is similar with which antibacterials?

A

macrolides, chloramphenicol

23
Q

Resistance of clindamycin is due to (give 3)

A
  1. mutation of ribosomal receptor site
  2. modification of receptor by a constitutively expressed methylase
  3. enzymatic inactivation of clindamycin
24
Q

Clindamycin can be used for the ff except

a. Meningitis
b. Severe acne
c. Pneumonia
d. Alternative for toxoplasmosis
e. Alternative for Strep, Staph infections for those allergic to B lactams

A

A, can’t penetrate CSF/Brain

25
Q

What is an alternative of trimethoprin-sulfametoxazole (cotrimoxazole) for moderate to moderately severe Pneumocystis jiroveci pneumonia in AIDS

A

Clindamycin + primaquine

26
Q

True of spectrum of activity of clindamycin EXCEPT

a. Gram + : S. penumonia, S. pyogenes, S. viridians, enterococci
b. Gram -: Capnocytophaga canimorsus, all others are resisant
c. Toxoplasma gondii, plasmodium
d. NOTA

A

A. no activity against enterococci

27
Q

Antibacterial that inhibit bacterial topoisomerase II (DNA hyrase) and topoisomerase IV

A

Quinolones

28
Q

1st gen quinolone

A

Nalidixic acid

29
Q

2nd gen quinolone EXCEPT

a. Ciprofloxacin
b. Ofloxacin
c. Levofloxacin
d. NOTA

A

C. Lovofloxacin, Gatilfloxacin, Moxifloxacin are 3rd gen quinolones

30
Q

Match Row A with Row B
A. Gatilfloxacin, Trovafloxacin
B. Hepatotoxic, hyper/hypoglycemia

A

Gatilfloxacin - Hypo/hyperGlycemia

Trovafloxacin - HepaToToxic

31
Q

Metabolism of quinolones via

A

liver - minimal to partial

32
Q

Elimination of quinolones via

A

renal

33
Q

Ciprofloxacin is drug of choice for

A

prophylaxis of anthrax

34
Q

Inhibits cell wall synthesis by binding firmly to the D-Ala-D-Ala terminus of nascent peptidoglycan pentapeptide, inhibiting transglycosylase thus preventing further elongation of peptidoglycan and cross-linking, leading to reduced structural integrity

A

Vancomycin

35
Q

How does eneterococci become resistant to vancomycin?

A

Modification of D-Ala-DAla binding site of peptidoglycan building block replacing D-Ala by D-lactate

36
Q

What is oral vancomycin solely used for?

A

C. difficile infection