Anti-bacterials Flashcards
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
C; Tetracyclines bind reversibly to 30s ribosome
Most ototoxic agents EXCEPT
a. neomycin
b. kanamycin
c. amikacin
d. tobramycin
e. AOTA
D;
Most nephrotoxic agents EXCEPT
a. Neomycin
b. Tobramycin
c. Amikacin
d. Gentamycin
e. AOTA
C.
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
B.
Ototoxic effects of gentamicin will manifest as _________, __________
tinnitus, verstibular damage
Enumerate 3 ways of tetra/doxy/minocycline resistance
- Impaired influx/increased effllux via Tet(AE) in Gram -
- Ribosome protection by Gram +
- Enzyme inactivation
Tetracycline GI absorption is impaired by the following EXCEPT
a. food (except doxy/minocycline)
b. divalent cations
c. alkaline pH
d. acids
D
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
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
D; other uses: treatment of acne, exacerbations of bronchitis, community-acquired pneumonia, Lyme disease, relapsing fever, leptospirosis, nontuberculous mycobacterial infections
Antibacteria that binds to 50s subunit of the bacterial ribosome and inhibits peptide bond formation
Chloramphenicol
Resistance to Chloramphenicol is due to
chloramphenicol acetyltransferase
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; must be adjusted for hepatic failure not renal failure
Antibacterial that binds to 50s subunit of the ribosomal RNA and prevents peptide chain elongation by blocking the polypeptide exit tunnel
Macrolides
What chemical structure relates macrolides together?
Macrocyclic lactone ring
Resistance of Macrolides are due to the ff. (give 3)
- reduced permeability of the cell membrane or active efflux
- Production of esterases that hydrolyze macrolides
- Modification of ribosomal binding site
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
D
Adverse reactions of Macrolides EXCEPT
a. GI intolerance
b. Hepatitis
c. Inhibit CYP450 in liver
d. Taste Perversion
e. NOTA
E.
What is the drug of choice in corynebacterial infections?
Macrolides
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
C
Among the macrolides, which does not inactivate CYP450?
Azithromycin
What is the MOA of clindamycin?
inhibits protein synthesis by interfering with formation of initiation complexes and with aminoacyl translocation reactions
Binding site of clindamycin is similar with which antibacterials?
macrolides, chloramphenicol
Resistance of clindamycin is due to (give 3)
- mutation of ribosomal receptor site
- modification of receptor by a constitutively expressed methylase
- enzymatic inactivation of clindamycin
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, can’t penetrate CSF/Brain
What is an alternative of trimethoprin-sulfametoxazole (cotrimoxazole) for moderate to moderately severe Pneumocystis jiroveci pneumonia in AIDS
Clindamycin + primaquine
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. no activity against enterococci
Antibacterial that inhibit bacterial topoisomerase II (DNA hyrase) and topoisomerase IV
Quinolones
1st gen quinolone
Nalidixic acid
2nd gen quinolone EXCEPT
a. Ciprofloxacin
b. Ofloxacin
c. Levofloxacin
d. NOTA
C. Lovofloxacin, Gatilfloxacin, Moxifloxacin are 3rd gen quinolones
Match Row A with Row B
A. Gatilfloxacin, Trovafloxacin
B. Hepatotoxic, hyper/hypoglycemia
Gatilfloxacin - Hypo/hyperGlycemia
Trovafloxacin - HepaToToxic
Metabolism of quinolones via
liver - minimal to partial
Elimination of quinolones via
renal
Ciprofloxacin is drug of choice for
prophylaxis of anthrax
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
Vancomycin
How does eneterococci become resistant to vancomycin?
Modification of D-Ala-DAla binding site of peptidoglycan building block replacing D-Ala by D-lactate
What is oral vancomycin solely used for?
C. difficile infection
