Antibiotics 3 and 4 Flashcards
polymyxin B
selective against G- enteric rods
binds LPS and then cytoplasmic phospholipids in membrane, causing membrane leakage
used as a topical agent
good against PA
daptomycin
lipopeptide that inserts into membrane of bacteria
cubicin
IV
only works on G+
aminoglycosides
bacteriocidal, ex. streptomycin, gentamycin
proposed mechanisms
binds to 30S distorting acceptor site and causing misreading that leads to bad proteins
at higher concentrations, it inhibits formation of the initiation complex
some bacteria are resistant. is inhibited under anaerobic or acidic conditions
streptomycin
only used for TB and select other
once used for G-
requires aerobic conditions
gentamycin
bacteriacidal
disrupts 30S ribosme, but also other things, so resistance cannot form in one step
requires aerobic conditions
under what conditions are aminoglycosides inhibited
anerobic, acidic conditions
tetracyclins
ex. tetracyline, doxycycline, minocycline
bacterioSTATIC
taken orally. broad spectrum. cant be taken pregnant or under 8.
inhibit 30 S ribosome
what are the important tetracyclins?
tetracycline, doxycycline, minocycline
inhibitors of 50S ribosome
erythromycin (macrolide) choramphenicol clindomycin azithromycin sreptogramins
erythromycin
bacterioSTATIC. blocks chain elongation. binds 50S
similar spectrum to penicillin G
azithromycin
related to erythromycin, but higher activity and broader spectrum. sustained tissue concentrations
bacterioSTATIC. binds 50S
chloramphenicol
bacterioSTATIC. blocks chain elongation. binds 50S
can cause lethal aplastic anemia.
useful against bowel anaerobes
clindamycin
STATIC. derivative of lincomycin. binds 50 S subunit
activity against G+ and anaerobes
binds 50S subunit. inhibits peptidyl transfer
sreptogramins
STATIC. binds 50 S.
potential for treating resistant bacteria- MRSA VREF, etc.
2 types: dalfopristin and quinupristin
what are the 2 types of sretpogramins
dalfopristin and quinupristen
combined form synergin