Antibiotics II: Inhibitors of Cell Wall Synthesis Flashcards
Beta-lactams: bactericidal or bacteriostatic?
bactericidal
Beta-lactams: time-dependent or concentration-dependent?
time-dependent
Mechanism of cell wall disruption by beta-lactams?
irreversibly inhibits transpeptidase; most effective in log phase of growth; target PBPs (penicillin-binding proteins)
G+ mechanism of resistance
secretion of beta-lactamases
standard, narrow-spectrum
Penicillin G, Penicillin V
Targets of penicillin
G+»>G-; anaerobic bacteria
DOC for syphilis
penicillin G
Penicillinase-resistant, narrow spectrum
Nafcillin
Use for Nafcillin
Pen G-resistant staph (MSSA) endocarditis, SSTIs (no G- activity)
Aminopenicillins, broad-spectrum
Amoxicillin
MOA for amoxicillin
activity against G- bacteria due to increased penetration through porins
Major use of amoxicillin
URIs
Antipseudomonal, extended-spectrum
ticarcillin, piperacillin
DOC for nosocomial G- infections
ticarcillin, piperacillin
beta-lactamase inhibitor
clavulanic acid
half-life of beta-lactams
short (30-90 min)
single dose repository prep given IM used for syphilis and prevention of rheumatic fever
pen G benzathine
Reaction common during therapy for syphilis
Jarish-Herxheimer (inflammatory response after lysis of organism)
large IV doses cause sodium overload –> CHF
ticarcillin
Pneumococcal, Streptococcal
Pen G