DD Unit III

Question 1

Drugs that are no good against gram (+) cocci

Answer 1

Aminoglycosides (Protein Syn Inhib) and Metronidazole (DNA inhibitor)

Question 2

Drugs that are no good against gram (-) rods

Answer 2

Penicillin, Vancomycin, Macrolides, Clindamycin, Metronidazole

Question 3

What is metronidazole good for anyway?

Answer 3

Kicks ass against anaerobes! (C. Diff and Bacteroides fragilis)

Question 4

Why don’t strep and MSSA have the same antibiotic profile?

Answer 4

MSSA has penicillinase

Question 5

Why is MRSA resistant to methicillin anyways?

Answer 5

New PBP means NO beta lactams (Pens, Cephs, Carba’s) are going to work

Question 6

So, what DOES work against MRSA?

Answer 6

Vancomycin, Macrolides, Tetracyclines, Clindamycin

Question 7

Tell me about enterococcus

Answer 7

Enterococcus is the most intrinsically resistant gram (+) cocci (NO CEPHS), in fact, it can resist Vanco in some cases!

Question 8

Tell me about enteroBACTER

Answer 8

Gram (-) rod, can carry AmpC on its chromosome

Question 9

What is AmpC and who carries it?

Answer 9

Broad spectrum beta-lactamase (Pens and Cephs). Chromosomally located, can be induced (amp, cefazolin) or constitutive. Enterobacter and Pseudomonas.

Question 10

How do you fuck up treating someone with enterobacter or pseudomonas infection?

Answer 10

(Assumes presence of AmpC) Give them any beta lactam except a carbapanem

Question 11

What soothes your E. Coli/Klebsiella (ESBL) and enterobacter/pseudomonas (AmpC) problems?

Answer 11

Treat with carbapanems!

Question 12

What two carbapenemases do we hate and who has them?

Answer 12

NDM-1 and KPC (like KFC, just death…) in Klebsiella and E. Coli

Question 13

You got N. gonnorrhoea. Bummer. What is it, and how do you treat it?

Answer 13

It is a gram (+) cocci, and due to altered PBP, only drug options = cephtriaxone, macrolides, or tetracyclines

Question 14

What’s the archetypical Gram (-) rod, and why doesn’t penicillin work against it?

Answer 14

E. Coli. Porins

Question 15

What does TEM-1 mean to you?

Answer 15

Plasmid carried by E. Coli. Amp and Amox go away.

Question 16

Tell me about ESBL

Answer 16

Lose pens and cephs. Carbs still work!

Question 17

What are aminoglycosides good for?

Answer 17

Gram (-) aerobes

Question 18

What two gram (-) rods have identical antibiotic spectrums, and what is the difference in their resistance?

Answer 18

E. Coli (TEM-1) and Klebsiella (SHV-1). These are both narrow beta-lactams, but Klebsiella has SHV-1 in its chromosome rather than a plasmid.

Question 19

What’s your go-to drug list for pseudomonas?

Answer 19

Pip/tazo, Ceftazidime/Cefipime, Aminoglycosides (gram neg rod duh), SOME carbapanems, SOME fluoroquinolones make pseudomonas moan

Question 20

What are you two C.Diff killers?

Answer 20

Vanco and Metronidazole (it’s an anaerobe!)

Question 21

What is the benchmark for an anaerobic drug?

Answer 21

Can it treat Bacteroides fragilis? Can’t treat with Cephs, Vanc, Macros, AMINOGLYS, Fluoros. CAN treat with a few pens, Carbas, Tetras, Clinda, Metro

Question 22

Uh oh, got Chlamydia…what to do?

Answer 22

Macrolides, Tetracyclines, Fluoroquinolones to the rescue!

Question 23

Got walking pneumonia…what to do?

Answer 23

Same as chlamydia! Macrolides, Tetracyclines, Fluoroquinolones

Question 24

Vancomycin is good for?

Answer 24

Gram + cocci and C. Diff

Question 25

Tell me the names of the macrolides

Answer 25

“ACE”

Azithromycin, Clarithromycin, Erythromycin

Question 26

Straight from lecture question: what DON’T you give to ppl with a penicillin/amox anaphylactic allergy?

Answer 26

Cephalosporins

Question 27

Name all the damn DQ CRIMES (non-renal clearance drugs, beware drug-drug interactions, genetic polys, hepatotoxicity)

Answer 27

Doxycycline 
Quinolones
Clindamycin
Rifampin
Isoniazid
Metronidazole
Erythromycin-like
Sulfonamides

Question 28

How do bacteria become resistant to macrolides?

Answer 28

modify the target: dimethylation of 23S rRNA on 50s subunit (erm gene). Confers cross-resistance to clindamycin too

Question 29

What are macrolides good for again?

Answer 29

Just about everything except gram (-) rods, enterococus and anaerobes

Question 30

Oh Shit, a bacteria’s got the erm…what’s the next important detail to know?

Answer 30

Is it inducible or constitutive?

Question 31

How do you fuck up with antibiotic treatment of a bacteria with the erm?

Answer 31

Treating with clindamycin can select for mutants that constitutively express the erm-encoded methylase = not only erythromycin resistance, but sudden failure of clindamycin therapy