Exam 3 (Ch. 10, 13, & 14) - Mja Flashcards
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.
When do we use the most unnecessary antibiotics?
Ear infections
what are mechanisms of antibiotic resistance?
-Production of enzymes that inactivate the drug (B-lactamase)
-altered porins (chromosomal mutation)
-altered target molecules (chromosomal)
-changing metabolic activity-producing more of an enzyme or not using a pathway (chromosomal)
-efflux pumps (R plasmids)
-biofilms-slower MR and diffusion of drug
-producing a protein that protects DNA from the drug (M tuberculosis a protein to protect DNA gyrase from fluoroquinolones.
What are ways to prevent development of resistance?
1.) Maintain high enough concentration of drug for sufficient time in patient.
2.) Drug cocktails-different targets OR synergism
3.) Don’t use antibiotics for non-bacterial infections
4.) Limit use of certain antibiotics to “save” them for MDR strains.
what are the five core actions from CDC reports.
Prevent infection and prevent spread of resistance. Tracking resistant bacteria. Improving the use of today’s antibiotics. Ivest in development of vaccines, therapeutics, and diagnostics. Improve sanitation and access to safe water (keep antibiotics out of environment)
Explain some characteristics of anti-viral drugs.
More difficult to achieve selective toxicity. More difficult to test. many are specific for certain viruses, but often difficult to test for the infecting virus.
What are the covid drugs and what are the mechanisms of them?
Remdesivir-RNA-dependent RNA polymerase inhibitor.
Paxlovid-Nirmatrelvir (protease inhibitor) + ritonavir (cytochrome P450 inhibitor)
Molnupiravir-RNA nucleoside that causes mutations in RNA viruses
What bacterial cell structures would you target for ABX development?
ETC, well wall, ribosome, cell membrane
what does Beta lactamase do?
Beta lactamase is secreted from the bacterial cell cleaves the antibiotic molecule and renders it in active
what are 3 mechanisms of resistance
1.) Mutation can alter the receptor that transports the drug, so that the drug cannot enter the cell
2.) Some drugs block the usual metabolic pathways, the cell can use an alternative pathway
3.) The cell can create a pump that pumps the drug out of the cell
What is the infectious process?
Attachment, Penetration, Uncoating, Biosynthesis, Maturation, Release
What are three ways animal viruses enter the cell?
1.) Direct Penetration
2.) Membrane Fusion
3.) Endocytosis
Name three DNA viruses and three RNA viruses.
Herpes, pox, parvo = DNA
corona, retro, arena = RNA
How do DNA viruses and retroviruses get their genome to the nucleus
This happens during mitosis when host DNA replicates and nuclear membrane dissolves
Tell me about antibiotic threats CDC reports
2.8 million people get antibiotic infections each year. Chlostridiodes difficile infections caused by antibiotics are very popular (223,900 hospitalized
What are the top 5 biggest antibiotic resistance threats?
Carbapenem-resistant Acinetobacter, Candida auris, carbapenem-resistant Enterbacteriaceae, C-diff, Drug-resistant Neisseria gonorrhea
