Antimicrobials Flashcards
overall, what are the 3 main types of antibacterial antibiotics?
- bacterial cell wall synthesis inhibitors
- bacterial protein synthesis inhibitors
- nucleic acid synthesis inhibitor
what are bacterial cell wall synthesis inhibitors usually used for?
those bacteria that are gram-stainable; cocci and rods
what are the 2 classes of bacterial cell wall inhibitors?
- beta lactams (penicillin, special penicillin, cephalosporins, carbapenem and monobactams)
- glycopeptide (vancomycin)
what is the general MOA of bacterial cell wall inhibitors?
binds to enzyme transpeptidase and prevents cross linking = weakened cell wall = lyse
*only works in actively dividing bacteria
what is the general side effect of bacterial cell wall inhibitors?
TOXICITY TO ALL:
- hepatotoxicity and neurotoxicity
- some extent of renal toxicity too
OTHERS:
- c-diff associated colitis
- SJS, Toxic epidermal necrosis
how is strep pneumo resistance conferred?
mutations to penicillin-binding receptors = not susceptible to beta lactams anymore
how is staph resistance conferred?
activation of mecA gene = production of beta lactamases = not susceptible to beta lactams anymore
what are examples of penicillin?
- benzylpenicillin
- cloxacillin
- amoxicillin
- piperacillin
what does benzylpenicillin target?
- gram pos and neg cocci
- some gram pos rods
- spiral bacteria: treponema pallidum
NOTE: usually for streps
what does cloxacillin target?
for MRSA
what does amoxicillin target?
same as benzylpenicillin (gram pos and neg cocci + gram pos rods)
additional: gram neg rod (listeria)
what does piperacillin target?
pseudomonas aeruginosa (who usually can also be targeted by the same tx for E. coli)
what are the examples of special penicillins?
co-amoxiclav (amoxicillin + clavulanate)
what does coamoxiclav target?
generally: gram neg and pos bacteria
but more so for bacteria causing LRTI and UTI
e.g. burkholderia pseudomallei, E. coli
what are the examples of cephalosporins?
1st/2nd gen
3rd gen: ceftriaxone, ceftazidime, cefixime
4th gen: cefepime
5th gen: ceftaroline
what does ceftriaxone target?
generally:
- gram pos and neg cocci
- gram pos and neg rods
what does cefapime target?
same as 3rd gen but extra coverage of pseudomonas
what does ceftaroline target?
widest coverage, including MRSA
what are the examples of carbapenems?
imipenem
what does imipenem target?
essentially same as the above but is only used in really really serious infections
what are the examples of monobactams?
aztreonam
what does aztreonam target?
alternative for penicillin allergic patients
but only targets gram neg cocci and rods
what are the examples of glycopeptides?
vancomycin
what does vancomycin target?
mostly gram positive cocci and rods
especially for MRSA and CDAC
note about vancomycin upon first administration
may cause red man syndrome
moving on from bacterial cell wall synthesis inhibitors, let’s talk about bacterial protein synthesis inhibitors - what are the diff classes of them?
30S inhibitors:
Tetracyclines
Aminoglycosides
Glycylcycline
50S inhibitors:
Macrolides
Clindamycin
Linezolid
what is the general MOA of protein synthesis inhibitors?
inhibits 30S/50S units of ribosomes and prevent binding of tRNA