Minor Cancer-Immunity-Personalized therapies (M_BCIPT19)
All documents for this subject (10)
Seller
Follow
nooralkemade
Reviews received
Content preview
Week 6: Infection and immunity III
History of antibiotics
Antimicrobials are one of the most successful medications ever because of their huge
benefits, low toxicity and costs.
Discovery of drugs:
● Arsenobenzenes + amino group → Salvarsan compound 606. Used to treat syphilis.
● Prontosil → used against streptococci. Nobel prize 1939.
● Prontosil’s active form was Sulfanilamide → involved in the inhibition of folate
biosynthesis.
● Penicillin → used in the war, mainly against soldiers with gonorrhoea instead of big
wound infections (because they cannot enter the field quickly.
Actinomycetes: When spores have a limited
supply of food, they degrade their hyphae to
get nutrients for the formation of new spores
→ but are vulnerable to others that want
nutrients. Therefore they produce antibiotics
as protection from bacteria = Waksman
screening platform
● Streptomycin is produced from a spore → first medicine against M. tuberculosis.
Now we have an antibiotic innovation gap:
● Scientifically: low-hanging fruit has been
picked.
● Economically: poor return on investment
● Regulatory: approval of new drugs has become
more difficult.
Overview of currently used antibiotics
The cell wall is important for the activity of antibiotics.
Gram-positive (one membrane) are therefore more
easily killed.
● Gram + = S. aureus & Streptococcus
● Gram - = E.coli, Salmonella, Klebsiella
pneumoniae.
So, therefore different antibiotics work on different
bacteria with different membranes. Special bacteria
are Chlamydia, Rickettsia and Mycobacteria.
Picture:
Bactericidal antibiotic = an
antibiotic that kills the bacteria.
Bacteriostatic antibiotic = an
antibiotic that inhibits growth.
Many antibiotics have been
discovered as natural compounds.
, 1st generation antibiotics: were not invented as medicine, just happen to work against
pathogens.
2nd generation antibiotics: tetracyclines → lower toxicity and can be manufactured to
change the working spectrum of the antibiotic.
3rd generation antibiotics: when bacteria develop resistance, these are needed. Can be
done to improve existing antibiotics by adding minor modifications.
B-lactam is the most important group of antibiotics ever discovered.
● B-lactam antibiotic (1e): Penicillin is an example.
○ Used to work against gram + like streptococci and some gram - like N.
meningitides.
○ The target is the peptidoglycan biosynthesis
○ More examples are:
■ Amoxicillin: good bioavailability → oral administration. excellent by
gram+
■ Flucoxallin: resistant to the action of penicillinase (made by bacteria to
prevent the action of penicillin). For infections of S.aureus.
■ Piperacillin: broad gram- activity like P.aeruginosa.
● B-lactam antibiotic (2e): Cephalosporins.
○ Originate from a natural compound, looks a lot like penicillin but with an R
group
○ Used in hospitals, mostly IV administration.
● B-lactam antibiotic (3e): Carbapenems
○ Natural compound.
○ Very broad gram +/-/ anaerobic activity
○ Agents of the last resort
● Resistance against B-lactam: beta-lactamases = hydrolysed the beta-lactam.
○ Can be inhibited by clavulanic acid or tazobactam
New antibiotics: working at the ribosome.
○ Aminoglycosides: against most gram -/staphylococci but not anaerobic.
Reading of the mRNA incorrectly.
○ Tetracyclines: very broad. Interfere in the tRNA and mRNA complex.
○ Macrolides: binds to the 50S portion → no translocation. Excellent
bioavailability.
○ Chloramphenicol: inhibits the formation of the peptide bond. Excellent
bioavailability.
DNA gyrase inhibitor: binding to DNA gyrase and topoisomerase IV → inhibition of the DNA
unwinding and DNA double-strand breaks.
○ The prodrug Metronidazole is reduced under anaerobic conditions.
○ Antabuse reaction to alcohol
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller nooralkemade. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $6.95. You're not tied to anything after your purchase.