Lecture 1 - Mechanisms of antibiotics Flashcards
Name the four antibiotic modes of action
Inhibiting cell wall synthesis
inhibiting protein synthesis
interfering with DNA synthesis
disrupting cell membrane
Name the 5 antibiotic groups that inhibit cell wall synthesis
Beta lactase - penicillins, cephalosporins, carbapenems
Glycopeptides - vancomycin, teicoplanin
How do beta lactams work?
block the active site of penicillin binding protein therefore preventing cross linking within the cell wall
Why do you combine beta lactams with clavulanic acid?
most bacteria secrete beta lactamase enzyme which hydrolyses the beta lactase ring within beta lactamase antibiotics. Clavulanic acid has a beta lactam ring which binds to the lactamase enzyme.
name one common beta lactam antibiotic combination
co-amoxiclav is amoxicillin and clauvanic acid
Name the 5 antibiotic groups that inhibit protein synthesis
aminoglycosides tetracyclines rifamycins macrocodes linosamides
give two properties of aminoglycosides and two examples
narrow therapeutic window and nephrotoxic
gentamicin and tobramycin
give two properties of tetracyclines and two examples
bacteriostatic - can’t be used in pregnancy or children
doxycycline and tiyecycline (broad spec)
when is tobramycin commonly used
to treat pseudomonas in cystic fibrosis
name a macrolide and when is it used
clarithromycin and community acquired pneumonia
name a rifamycin + when is it used
rifampicin and TB
Name a lincosamide
clindamycin
how do glycopeptides work
prevent cross linking of cell wall by blocking the binding site of penicillin binding protein
What are glycopeptides active against?
broad spec gram positive
Name two antibiotic groups that inhibit DNA synthesis and how they work
sulphonamides and diaminopyramidines
inhibit folate synthesis
name a diaminopyrimidine and give an example of when it should and shouldn’t be used
trimethoprim shouldn’t be used in the first trimester of pregnancy and should be used with UTIs
1) Name an antibiotic group which works by inhibiting DNA replication
2) mechanism
1) quinolone - ciprofloaxin
2) stops the DNA unwinding
are fungal cells prokaryotes or eukaryotes ?
eukaryotes
organise these mycosis (fungal infections) from most superficial to deep:
candidiasis, aspergillios, tinea, murcomycosis
tinea > candidiasis > myrcomycosis > aspergillios
name the three main anti fungal groups and briefly describe how each of them work
polyenes - bind to ergosterol in cell membrane
azoles - inhibit ergosterol synthesis
echinocandins - inhibit gluten synthesis needed for cell wall
categorise these beta lactams and one property of each: ertapenem fluoxacilin ceftazidime ceftazidime meropenem
categorise these beta lactams and one property of each: PENICILLINS = fluoxacilin - better against staph CEPHALOSPORINS= ceftazidime - good against pseudo cefalexin - CARBAPENEMS = ertapenem - oral meropenem - broad spec
