21 - Antibiotics. Targets and modes of action

What did Yersinia pestis cause?

Black death

Who discovered antimicrobials / concept of the ‘magic bullet’?

Paul Ehrlich

What is selective toxicity?

Kill target pathogen and leave host unharmed

What is Salvarson?

Contains arsenic, cured syphilis caused by Treponema pallidum

What 2 drugs have B lactam ring for activtiy?

Penicillin / cephalosporin

What does tetracycline bind to?

bind to 30s subunit

What does aminoglycosides bind to?

bind to 30s ribosomal subunit

Is aminoglycosides bacteriostatic or bactericidal?

bactericidal

What does macrolides bind to?

bind to 50s subunit

What does fluoroquinolones bind to?

Bind to DNA gyrase

What does Fluoroquinolones do?

Prevent gyrase from supercoiling DNA / inhibit DNA replication

What do sulphonamides do?

Competitively inhibit dihydropteroate synthase required for folate synthesis

What does trimethoprim do?

Inhibit dihydrofolate reductase

What type of bacteria do Texiobactin target?

target Gram +ve

What effects do Texiobactin cause?

Cause membrane defects by displacing polar lipid headgroups / reduce membrane thickness

What do aminoglycosides do?

Creates fissures in outer cell membrane, result in leakage of intracellular contents & enhanced antibiotic uptake / cell lysis

What type of bacteria are aminoglycosides only effective on?

Aerobic bacteria

What do macrolides do?

Prevent incoming tRNA and attached AA from binding to nascent polypeptide chain