Flashcards in Antimicorbial: protein synthesis inhibitors Deck (56)
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1
What is selective toxicity?
the drug blocks a reaction that is vital to both
the microbe and host but has greater impact on the microbe
2
do humans hav e a 70s ribosome?
yes, mitochondrial
3
What is the one drugs that attaches tRNA synthetas?
mupirocin
4
What protein subunit doe each of the following drugs affect?
1.Tetracycline
2 aminoglycosides
3spectinomycin
4macrolides
5chloramphenicol
6streptogramins
7oxazolidinones
8lincosamides?
1. 30
2.30
3.30
4.50
5.50
6.50
7.50
8.50
5
What is the selective toxicity of tetracyclines? static or cidal?
1. 70s mitoch. ribosomes, not cytoplasmic ribosomes
2. static
6
How is resistance incurred against tetracyclines?
1. decreased intracellular levels
a. decreased influx
b. increased efflux
2. enzymatic inactivation of drug
3. expression of proteins that
protect ribosomes from drug
7
What are key points about tetracyclines absorption?
oral is variable
-decreased by divalent and trivalent cations found in dairy and iron supplements
- decreased when gastric pH is elevated
8
Is the distribution of tetracyclines wide or narrow?
Very wide- accumulation in spleen, bone marrow, bone, dentine, enamel of teeth, crosses BBB and placenta
9
Where is excretion of most tetracyclines? what are the two exceptions
1. most through kidneys with some bile/reabsorbed
2. a. doxycycline- inactive chelate/conjugate in feces
b. minocycline-metab. by liver and passed in feces.
10
What are the two most common things treated with tetracyclines?
Acne
Riskettsial diseases
11
Who should tetracyclines absolutely not be given to?
pregnant women and children under 8--->discoloration of teeth
12
What type of superinfection is common with the use of tetracyclines?
pseudomembranous colitis
13
Tetracyclines especially effects which drugs?
bactericidal antibiotics (penicillins)
- digoxin, oral anticoagulants, oral hypoglycemics do to effects on liver and kidney
14
Tigecycline is especially effective against what>
-strains that are get-resistant
-hershey isolate of MRSA
15
What gourd of drugs should we think if we see it end with acin or micin or mycin? are they static or tidal? irreversible or reversible binding to 30S?
1. aminoglycosides
2. bactericidal
3. irreversible
16
T-F- aminoglycosides have concentration dependent killing with significant PAE?
True
17
What accumulates when using amino glycosides?
streptomycin monosomes-->blocks further translation of messages
18
What spectrum of bacteria are aminoglucosides? combination with what?
1. Gm- aerobes
2. penicillin or vancomycin
19
How is resistance incurred with amino glycosides?
1. mutant bacterial ribosome
2. decreased uptake or efflux
3. enzymatic inactivation of the drug
20
How are aminglycosides administered? why? clearance?
1. IM or IV
2. highly polar and poorly absorbed through GI
3. renal clearance
21
What is distribution like for the amino glycosides?
not well distributed to most cells, eye or CNS
High concentration only in inner ear and renal cortex--> toxicities (reversible)
22
What limits the use of streptomycin?
high resistance
23
When is gentamicin used topically? how is resistance conferred against gentamicin? is the vestibular ototoxicity reversible?
1. burns, wounds, skin lesions
2. poor drug uptake
3. no
24
What is slightly more active against pseudomonas than gentamycin? What else is it often used for?
1. tobramycin
2. P. aeruginosa RTI w/ cystic fibrosis
25
What is the semisynthetic derivative of kanamycin and has reduced toxicity? what does it treat?
1. amikacin
2. Bugs resistant to gentamicin, treats M. tuberculosis
26
Widespread use of what during bowel surgeries led to resistance and enter colitis outbreaks? what does this mean>
1. neomycin/kanamycin
2. limited to topical and oral use
27
Is spectinomycin an aminoglycoside? how do we administer?
1. NO!!! aminocyclitol
2. IM
28
What type of antibiotics should we think when we see romycin or domycin?
macrolides
29
Are macrocodes static or cidal? because of proximity of their sites of action, they competitively inhibit what? G+ or G- more?
1. static
2. ribosome binding of
streptogramins, clindamycin,
chloramphenicol
3. G+
30
