Lecture 12 3/7/24 Flashcards
How do cephalosporins differ from penicillins?
the beta-lactam ring is attached to a 6-membered ring in the cephalosporin, making it more resistant to beta-lactamases
What are the characteristics of cephalosporin pharmacokinetics?
-poor oral absorption
-short half-lives
-renal elimination
-considerable renal accumulation
-time-dependent activity
What are the cephalosporin classifications and admin. routes?
-1st gen: parental, oral
-2nd gen: parenteral
-3rd gen: parenteral, oral
-3rd gen, anti-pseudomonal: parenteral
-4th gen: parenteral
What is the spectrum of first gen. cephalosporins?
-high susceptibility of gram pos. aerobes and FAs
-decent susceptibility of gram pos. anaerobes and gram neg. aerobes
-some susceptibility of gram neg. anaerobes and FAs
Which bacteria exhibit resistance against first gen. cephalosporins?
-MRSA
-MRSP
-Enterococcus spp.
-Pseudomonas spp.
-Enterobacter spp.
-Bacteroides fragilis
What is the parenteral first gen. cephalosporin?
cefazolin
What are the oral first gen. cephalosporins?
-cefadroxil
-cephalexin
What is the intramammary first gen. cephalosporin?
cephapirin
What is the spectrum of second gen. cephalosporins?
-decent susceptibility of gram pos. bacteria
-high susceptibility of gram neg. bacteria
Which second gen. cephalosporin is able to treat Bacteroides fragilis and other anaerobes?
cefoxitin
Which bacteria exhibit resistance to second gen. cephalosporins?
-Pseudomonas
-Enterococcus spp.
-MRSA
What are the general characteristics of second gen. cephalosporins?
-limited applications in animals
-more expensive than first gens.
-used based on susceptibility test results
What is the spectrum of third gen. cephalosporins?
-high susceptibility of gram pos. and neg. aerobes, gram neg. FAs
-decent susceptibility of gram pos. anaerobes
-decent susceptibility of gram pos. FAs and gram neg. anaerobes EXCEPT Bacteroides
Which bacteria exhibit resistance to third gen. cephalosporins?
-some Serratia spp.
-some Enterobacter spp.
-Pseudomonas aeruginosa
-Enterococci
-MRSA
-MRSP
What are the main uses of third gen. Ceftiofur?
-resp. infections in food animals
-UTIs in small animals