Therapy for Staph and Strep I Flashcards Preview

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Flashcards in Therapy for Staph and Strep I Deck (36):
1

Concentration dependent

Increase the rate of bacterial killing as the antibiotic concentration increases.

2

Concentration dependent drug examples

Lipopeptides (daptomycin), aminoglycosides, fluoroquinolones

3

Time dependent

Killing is predicted by the time that the concentration is above a certain level called the MIC (minimum inhibitory concentration)

4

Time dependent drug examples

Beta-lactams, glycopeptides (vancomycin)

5

MIC

Minimum inhibitory concentration, the lowest concentration of an antibiotic that will inhibit the visible growth of bacteria in vitro.

6

Broth Macrodilution

Put different concentrations of antibiotic into test tubes with bacteria. See which one is the first without cloudiness.

7

E Test

Uses a strip with varying doses of antibiotic. Place on a dish, read the zone of inhibition.

8

Bacteriostatic drugs and example

Arrest bacterial growth (linezolid)

9

Bactericidal drugs and example

Kills bacteria (beta lactams, etc).

10

Is vancomycin bacteriostatic or bactericidal?

It depends on the organism!

11

Beta Lactam Antibiotics

Penicillins: Amoxicillin, Ampicillin, Nafcillin, Penicillin

Cefalosporins: Cefazolin (first generation)

12

How do beta lactams work?

Bind to PBPs and inhibit transpeptidases.

13

What is the best orally absorbed penicillin?

Amoxicillin

14

How are penicillins eliminated?

Renally, with the exception of nafcillin.

15

Natural penicillin is drug of choice for...

S. pyogenes, S. galactiae, treponema pallidum (syphilis).

16

Penicillin G vs Penicillin V

Penicillin G is IV preparation whereas penicillin V is acid stable and can be taken orally.

17

Problem with natural penicillin?

Susceptible to penicillinases especially in Staph aureus.

18

Anti-staphylococcal penicillin

Nafcillin (IV), resistant to penicillinase. No gram-negative activity.

19

Does nafcillin work on gram negative organisms?

No.

20

What organisms does natural penicillin work on?

Gram positive cocci, gram negative cocci, gram positive bacilli, spirochetes.

21

Extended Spectrum Penicillins (amino-penicillins)

Ampicillin and amoxicillin (both oral).

22

What are amino-penicillins the drug of choice for?

Listeria monocytogenes

23

What organisms do amino-penicillins work on?

Gram positive organisms, some gram negative activity, some anaerobic activity, ENTEROCOCCI.

24

What must organisms have to be affected by beta lactams?

Peptidoglycan wall (mycoplasma is inherently resistant)

25

How is MRSA so drug resistant?

It has an altered PBP that has lower affinity for all beta lactams except ceftaroline.

26

Betalactamase inhibitors

Clavulanic acid, Sulbactam, tazobactam. Abundant in STAPH AUREUS

27

Betalactamase inhibitors combined with beta lactams

Clavulonic acid and amoxicillin = augmentin
Sulbactam and ampicillin

These have increased gram negative activity.

28

Penicillin hypersensitivity

Penicilloic acid can cause IgE mediated hypersensitivity

29

Penicillin rash common in patients with...

EBV

30

Penicillin diarrhea caused by

alterations in the commensal flora of the GI tract. C diff can overgrow

31

Why isn't methicillin used clinically?

Because it can cause nephritis

32

Cephalosporins

5 generations. Higher generations have increased gram negativity and higher Vd.

33

Cefazolin used for

Gram positive cocci like staph aureus, strep (GAS, GBS, viridans), also some activity against gram negative bacilli (e.coli)

34

What can't cephalosporins treat?

Enterococci or listeria

35

Is cefazolin penicillinase resistant?

Yes!

36

Adverse reactions of cephalosporins

Hypersensitivity