Exam 3 (Ch. 10, 13, & 14) - Mja Flashcards
(40 cards)
Where did the antibiotics Penicillin originate from?
a mold
Who discovered the first anti-microbial drug?
Paul Ehrlich and Sahachiro Hato
-Salvarsan, an aresenic compound to treat syphilis, which was a big problem in the early 1900s
What is Therapeutic index
the range of therapeutic dose to toxic dose.
(a high TI because it has a larger wiggle room for dosage)
What are sulfa drugs?
-1932 in Germany, the red dye prontosil was found to inhibit growth of S. aureus in animals.
-didn’t work on cultures
-sulfanilamide is the breakdown product and is the active form
what anti-bacterial enzyme did Alexander Fleming discover in tears and saliva?
Lysozyme
Why would bacteria make antibiotics?
They use it as a defensive mechanism to compete with other bacteria to prevent growth of them.
What specific antibiotics inhibit cell wall synthesis?
Penicillin, cephalosporin, vancomycin
What specific antibiotic disrupts cell membrane function?
polymyxin
What specific antibiotic inhibits translation?
tetracycline, erythromycin, streptomycin, chloramphenicol.
What specific antibiotic inhibits metabolism?
sulfonilamide
what specific antibiotic inhibits transcription?
rifamycin
What specific antibiotic inhibits DNA replication?
quinolones
What do B-lactam drug do?
they are bactericidal against a variety of bacteria; inhibit penicillin-binding proteins. Resistance is due to synthesis of B-lactamases, decreased affinity of penicillin-binding proteins, or decreased uptake.
what are the characteristics of natural penicillin?
They are active against Gram-positive and a few gram-negative bacteria.
What are the characteristics of penicillinase-resistant?
They are similar to natural penicillin, but resistant to inactivation by the penicillinase of staphylococcus.
What are the characteristics broad-spectrum penicillin?
They are more active against gram-negative organisms
What are the characteristics of extended-spectrum?
They have increased activity against gram-negative rods, including pseudomonas species.
What mechanism do B-lactam drugs do to interfere with the bacteria?
Interfere with the formation of the peptide side chains between adjacent strands of peptidoglycan by inhibiting penicillin-binding proteins.
What mechanisms do vancomycin do to bacteria?
vancomycin binds to the amino acid side chains of NAM molecules interfering with peptidoglycan synthesis.
list three ways antibiotics affect ribosomes:
a.) some aminoglycosides (streptomycin) cause change in the 30S shape, so mRNA is misread
b.) tetracyclines and some aminoglycosides block docking site of tRNA
c.) chloramphenicol blocks peptide bond formation
d.) lincosamides or macrolides bind to 50S subunits, blocking proper mRNA movement through ribosomes. Synthesis stops.
e.) antisense nucleic acid (double stranded RNA)
f.) blocks binding site of ribsomes binding together.
What specific action does sulfa drugs do on amino acid synthesis?
sulfa drugs block the enzyme the transition of precursor #1 and precursor #2
What specific action does trimethoprim do to block production of amino acids?
Trimethoprim blocks the transition of Dihydrofolate to tetrahydrofolate.
What are the considerations when prescribing an antibiotic?
-spectrum of action (is broad-spectrum always better?)
-effectiveness
What are the routes of Administration?
Topical, oral, Intramuscular, IV.