Antimicrobials

Question 1

What are the first generation cephalosporins?

Answer 1

Cefazolin (Cfz), Cephalexin, Cephalothin (Cf)

Question 2

What are the second generation cephalosporins?

Answer 2

Cefotetan (Ctn), Cefoxitin (Cfx), Cefuroxime (Crm)

Question 3

What are the third generation cephalosporins?

Answer 3

Ceftriaxone (Cax), Cefotaxime (Cft), Ceftazidime (Caz),

Cefpodoxime (Cpd), Cefixime (Cfe)

Question 4

What are the cephamycins?

Answer 4

Cefoxitin, Cefotetan, Cefmetazole

Question 5

How are cephamycins different than other second generation cephalosporins?

Answer 5

They have good ANAEROBIC coverage. Similar spectrum of activity to 2nd generation otherwise.

Question 6

When might you use a cephamycin preferentially?

Answer 6

Prior to belly surgery. Lots of anaerobes in the gut and if there is any breach, cephamycin anaerobic activity is wanted.

Question 7

What is the spectrum of activity for first generation cephalosporins?

Answer 7

Good: MSSA, Strep
Moderate: some enteric GNRs
Poor: Enterococcus, anaerobes, MRSA, Pseudomonas

Question 8

When do you use 1st gen cephalosporins?

Answer 8

Skin and adnexal structure infections
Surgical prophylaxis
MSSA endocarditis

Question 9

What is the spectrum of activity for 2nd generation cephalosporins?

Answer 9

Good: some enteric GNRs, Haemophilus, Neisseria
Moderate: Strep, Staph, Anaerobes (cephamycins only)
Poor: Enterococcus, MRSA, Pseudomonas

Question 10

When do you use 2nd gen cephalosporins?

Answer 10

URI, CAP, Gonorrhea, Surgical prophylaxis (cephamycins)

Question 11

What is the spectrum of activity for 3rd generation cephalosporins?

Answer 11

Good: Strep, enteric GNRs, Pseudomonas (ceftazidime)
Moderate: MSSA (not ceftazidime)
Poor: Enterococcus, Pseudomonas (except ceftazidime), anaerobes, MRSA

Question 12

What are the fourth generation cephalosporins?

Answer 12

Only one: Cefepime

Question 13

What is the spectrum of activity for 4th generation cephalosporins?

Answer 13

Good: MSSA, Strep, Pseudomonas, enteric GNRs
Moderate: Acinetobacter
Poor: Enterococcus, anaerobes, MRSA

Question 14

When do you use 4th generation cephalosporins?

Answer 14

Febrile neutropenia, nosocomial infections

Question 15

When do you use 3rd gen cephalosporins?

Answer 15

Lower respiratory tract infections
Pyelonephritis
Nosocomial infections and febrile neutropenia -- ceftazidime only
Lyme disease -- ceftriaxone
Meningitis
Gonorrhea
Skin and adnexal structure infections

Question 16

Which Enterobacteriaceae are intrinsically resistant to Ampicillin?

Answer 16

All except E. coli and P. mirabilis (although they can have Beta-lactamases that render it resistant)

Question 17

What are the AmpC organisms?

Answer 17

M- Morganella morganii
S- Serratia
P- Providencia
A- Klebsiella aerogenes
C- Citrobacter freundii
E- Enterobacter cloacae

Question 18

What is AmpC?

Answer 18

Chromosomally encoded Beta-lactamase that cleaves all penicillins, cephalosporins and cephamycins. Can have a spectrum of activity and be inducible or constitutively active.