Lecture 2 Flashcards
Vancomycin is a _____
glycopeptide
Vancomycin inhibits cell wall _____ formation by binding to the _____ side chain of cell wall precursors
Peptidoglycan;
D-ala D-ala
Vancomycin treats gram __ bacteria only, and is bacterio____
+, cidal
VRE’s appeared after the use of ____, a glycopeptide antibiotic, was used as a feed additive in live stock
avoparcin
Mechanism of VRE resistance:
mutation of PG cell wall precursor from D-ala D ala to D-ala-D-lactate
Side effects of vancomycin: NOT
Nephrotoxicity,
Ototoxicity,
Thrombophlebitis
Vancomycin can cause ___ man syndrome, which is diffuse flushing of the skin due to ____
red;
histamine
Macrolides are macrocylic ____, usually __-membered rings
lactones; 14
Macrolides are poly____, because they are produced by sequential addition of ____ groups to a growing chain
ketides;
proprionate
Mechanism of Macrolides:
bind reversible to the __ site of the ribosome, inhibiting ____ of the peptidyl-tRAN from the __ to the ___ site
P; translocation;
A; P
Macrolides typically bind the ___ RNA of the ___ ribosomal subunit
23S; 50S
Mechanisms of macrolide resistance:
____ is induced to degrade the macrolides
efflux pump ejects the drugs via ____ transport
lactone ethyl hydrolase
active
Mechanisms of macrolide resistance:
Drug induced production of an RNA _____. A specific adenine base on the ___ RNA molecule of the 50s ribosomal subunit is ____
methylase
23s
methylated
Mechanisms of macrolide resistance:
mutation of ___ to ____ at the specific site A2058
Adenine to guanine;
reduces affinity
Macrolides can be inactivated under ____ conditions by a process involving the ___ group
acidic
6-OH
Acidic conditions cause ___ formation in macrolides, inactivating them and causing GI ____
ketal, cramping
Clarithromycin is more acid ____ due to blocking ketal formation via a 6-____ derivative
stable
6-OCH3
Azithromycin is acid ____ due to it being an ____ analog
stable
amine
The main route of erythromycin metabolism is ____ in the liver. It is eliminated mainly via ____
demethylation
bile
Erythromycin and clarithromycin bind and _____ _____ and related P450 encymes
inhibit CYP3A
Inhibition of CYP450 causes an _____ in activity of other drugs, besides ____, which is a CYP inducer
increase
Rifampicin
Side effects of macrolides can be remembered by: _____
MACRO
The M in MACRO stands for _____
Motility (GI issues)
The A in MACRO stands for ____ caused by long _____ interval
arrhythmia; QT
The C in macro stands for _____. It is reversible/irreversible
cholestatic hepatitis; reversible
The R in MACRO stands for ____. Serious side effects related to this term include ____ and _____
Rash;
stevens-johnson syndrome;
toxic epidermal necrolysis 0_0
the O in MACRO stands for ____
eOsinophilia
There is an increased risk of ____ ____ in children whose mothers took erythromycin
pyloric stenosis
Erythromycin reaches high concentrations in _____, which transport it to the site of the infection
phagocytes
Erythromycin ____ ____ is the ester prodrug of erythromycin. It is more ____ and thus has increased absorption following oral administration
ethyl succinate;
lipophillic
_____ is the C6 methyl ether of erythromycin. This blocks ____ formation and increases oral stability
clarithromycin;
ketal
The 14-R-hydroxy metabolite of _____ has greater antibiotic activity than the drug itself, especially against _____
clarithromycin;
H Influenzae
Azithromycin is a __-membered ring due to an added ____ group
15;
N-CH3
____ AND ____ present in some antiacids form coordination complexes with ____ and prevent absorption
Magnesium, aluminum;
azithromycin
______ has greater activity against Gram - bacteria than the other macrolides
Azithromycin
