15: antibiotics

Question 1

how penicilin is discovered?

Answer 1

alexander fleming worked on staphlycoccus & noticed the lack of bacteria surround the colony (Penicilium)
=> failed to isolate subst from the mold
=> called in Penicilin

Question 2

broad spectrum vs narrow spectrum antiobiotic

Answer 2

if drug target pathogen from many taxonimic group, even beneficial series = broad spectrum
if few groups tartgeted = narrow spectrum

Question 3

how sulfonamides cause bacterial death?

Answer 3

By cell wall synthesis!

Since folic acid needed for DNA synthesis, folic acid needs PABA

In structure, SMZ is similar to PABA : fit into the active site of enzyme & compete w/ PABA

=> block folic acid synthesis => no nucleotide synthesis => bacterial death

Question 4

how beta lactam antiobiotics cause cell death?
examples?

Answer 4

BY cell wall synthesis!

When cells growing & dividing, h=ave to add NAG-NAM subunits
Transpeptidase cross link the new subunit
Penicilin e.g block it

=> Cell wall is weak, lyse due to osmotic P

Penicilin, Cephalosporin, meropenum

Question 5

how have bacteria resist penicilin?

Answer 5

Beta-lactamase enzyme cut out the beta-lactam ring
Convert it to penicilloic acid, which is not hamrsul to bacteria

Question 6

2 ways to determine bacterial subsceptibility to antiobiotic

Answer 6

1/ put = amnt of 2 bacterium onto plastic plate
diff concentra of antiobiotic
=? find min. concentra to kill the bacteria
2/ diff concentra of antibiotic onto agar plate
Zone of inhibition used to find min. concentra

Question 7

why the rise in antibiotic resistance?

Answer 7

Overall misuse of antibiotics and innovation gap
Most major drug groups created btw 1930-1930
Lack of new classes since then

1. Prescription abuse: from drug companies & doctors
2. Prescription misuse from personal: self-diagnosis & eating leftoevers
3. …from health organization: overdosing it in hospital
4. abuse on lifestock: in feed

Question 8

strategies to develop antibiotic resistance

think 3 modifications

Answer 8

1. antibiotic hydrolysis: split apart the antibiotic
2. …modification: change/ add chemical molec
3. membrane modification / efflux: inhibit drug entry into cytoplasm & project it back
4. target modification: alter cell structure targeted by antibiotics
5. alter metabolic pathways: some drugs are competitive inhibitor
   => create alternate patjways to make = product

Question 9

antibiotic to fight ____ disease bt not ____ ____ because it’s diffcult to find drugs to harm ____ without being toxic to ____ ____

remind of theurapic window

Answer 9

bacterial / microbial pathogens / pathogens / host tissue

Question 10

developing antibiotic resistence via…, (redacted) change to DNA

Answer 10

mutation = rare, spontaneous change to DNA; often from DNA replication
may transfer horizontally from other bacteria

Question 11

new approach to antimicorbial therapy

Answer 11

careful use of antibiotics: preseve ones that are still effective via prudent use and educated medical corp
find new ones!