L5 Cushman Flashcards
2 main structures for aminoglycosides
streptidine and 2-deoxystreptamine
aminoglycoside MOA
bind to 30S and inhibit protein synthesis. also bind to 16S (part of 30S) rRNA forming THE A SITE. interferes with INITIATION COMPLEX*
selection of wrong amino acids during 30S binding from aminoglycosides causes something known as
“nonsense proteins”
T or F:
aminoglycosides cause a frame shift in bacterial cell wall as a part of its mechanism
true
T or F:
aminoglycosides have a negative charge
false, positive which lets them through the outer membrane (polarity)
T or F:
aminoglycoside passage through cytoplasmic membrane is a passive transport process due to its positive charge
false, it is ACTIVE TRANSPORT
resistance mechanisms for aminoglycosides (3)
- metabolism: bacteria inactive aminoglycosides by acetylation, adenylation, and phosphorylation
- altered ribosomes
- altered aminoglycoside uptake: altered target site/mutation in target site (i think)
all aminoglycosides have which two toxicities
ototoxicity (irreversible) and nephrotoxicity (reversible)
aminoglycosides can also cause respiratory paralysis, how do you treat this?
neostigmine or calcium gluconate
aminoglycosides are used for their activity against gram ____ bacteria in practice
negative
T or F:
aminoglycosides are often used in combo with penicillins
true
tuberculosis:
A. tobramycin
B. Gentamycin
C. Steptomycin
D. Neomycin
C
most important aminoglycoside
gentamycin
widely used parenterally to treat gentamycin-resistant Pseudumonas aeruginosa
A. tobramycin
B. Gentamycin
C. Streptomycin
D. Neomycin
A
used topically in burn patients
A. tobramycin
B. Gentamycin
C. Steptomycin
D. Neomycin
B
what are the 4 orally used aminoglycosides
neomycin B
paromomycin
streptomycin
Plazomicin
treat amoebic dysentery and tapeworms
neomycin B
paromomycin
streptomycin
Plazomicin
paromomycin
against bubonic plague and TB
neomycin B
paromomycin
streptomycin
Plazomicin
streptomycin
treat complicated UTIs (including pyelonephritis)
neomycin B
paromomycin
streptomycin
Plazomicin
Plazo
what class is erythromycin
macrolide
what is the important part of the structure of macrolides for activity
desosamine sugar
macrolide antibiotics are ________
polyketides
what is the easy way to identify a macrolide structure
the polyketide is alternating methyl groups
pka of erythromycin
8.8
macrolide MOA
inhibit bacterial protein synthesis by binding the P site of bacterial ribosome. mainly involves binding 23S and not the protein itself.
T or F:
macrolides primarily bactericidal
false, bacteriostatic
macrolides tend to accumulate within ___________ and are actually transported into the site of infection
leukocytes
resistance mechs for macrolides (4)
- lactone ester hydrolase induced to degrade macrolides
- drug-induced production of RNA methylase
- mutation of adenine to guanine at A2058***
- an efflux pump ejects drugs from cell by ACTIVE transport**
___________ spp and ________ spp exhibit intrinsic resistance by not allowing entry of macrolides
pseudomonas + enterobacter
what kind of chemical reaction can inactivate the parent molecule under acidic conditions for macrolides
acid-catalyzed ketal formation
what drug is administered as enteric coated tabs
oral erythro
if you make a macrolide more stable in acid what does this mean for admin
better oral absorption
main route of erythromycin metabolism
demethylation in liver
T or F:
erythomycin and clarithromycin inhibit 3A4
true
erythromycin is primarily used for infections of ____ and ____ _______ primarily caused by GP bacteria
skin and soft tissue
unique side effect of macrolides
SJS*
erythromycin is absorbed (slowly/rapidly) and diffuses into most tissues and _________
rapidly, phagocytes
_____ provide a very efficient drug delivery mechanism for erythromycin
phagocytes (again)
