Other Beta-Lactams Flashcards
what is the distribution of cephalosporins?
mostly extracellular
how are cephalosporins excreted?
renal filtration +/- secretion
are first-generation cephalosporins affected by penicillinase?
no: good activity against most Staphylococcus
used frequently for skin and bone infections
why are first-generation cephalosporins not as reliable against obligate anaerobic bacteria, especially gram-negative anaerobes?
anaerobes can make cephalosporinases
what are the common agents of first-generation cephalosporins?
cephalexin
cefazolin
cephapirin
second generation cephalosporins have better ___________________ than first-generation cephalosporins
gram-negative activity
what makes cefoxitin and cefotetan unique among cephalosporins?
good anaerobic activity: including Bacteroides fragilis
4-quadrant coverage
what is the gram negative and positive activity like of third generation cephalosporins?
increased gram negative activity
slightly lower gram positive activity than first generation drugs
what allows therapeutic concentrations of third-generation cephalosporins to cross the blood brain barrier?
low MICs and low to moderate protein binding
what are the drugs of choice for bacterial meningitis?
third-generation cephalosporins
what are the common agents of veterinary cephalosporins?
cefpodoxime proxetil
cefovecin
ceftiofur
naxcel
excenel
excede
what are the approved uses of cefovecin in the US?
skin infections dogs and cats
injectable approved for use every 7-14 days in dogs and cats
is there milk withdrawal with systemic administration for ceftiofur?
no
what formulation is excede (ceftiofur crystalline free acid)?
repository formulation
what is the spectrum like in carbapenems?
perhaps broadest spectrum of activity of any antimicrobial
what pathogens are carbapenems very effective against?
staphylococci
streptococci
obligate anaerobes
Pseudomonas aeruginosa
are carbapenems effective against E. coli?
yes, very
are cephalosporins able to cross the blood brain barrier?
third generation cephalosporins
what is the metabolism of cephalosporins?
limited, depends on agent
how are first generation cephalosporins different than narrow-spectrum penicillins?
not affected by penicillinase
slightly better gram negative activity
not as reliable against anaerobic bacteria, especially gram negative anaerobes
what is used for perioperative prophylaxis?
cefazolin
for the four quadrants, how does cephalexin fair?
E. coli: +/-
Staphylococcus: ++
Streptococcus: +
anaerobe: *
for the four quadrants, how does cefazolin fair?
E. coli: +
Staphylococcus: ++
Streptococcus: +
anaerobe: *
what is one second-generation cephalosporin?
cefoxitin
what makes cefoxitin less susceptible to cephalosporinase produced by anaerobes?
structurally cephamycins, not cephems
how does cefoxitin do with the four quadrants?
E. coli: ++
Staphylococcus: ++
Streptococcus: +
anaerobe: +
what allows third generation cephalosporins to cross the blood brain barrier?
low MICs and moderate protein binding
what is the four quadrant coverage of cefotaxime/third generation cephalosporins like?
E. coli: +++
Staphylococcus: ++
Steptococcus: +
anaerobe: +/-
what is considered the first or second tier drug for pyoderma in dogs?
Cefpodoxime proxetil
what is the activity of carbapenems against the four quadrants?
E. coli: +++
Staphylococcus: ++
Streptococcus: +
anaerobe: +
