8.1 PCN Flashcards Preview

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Flashcards in 8.1 PCN Deck (25):
1

In general, how do B-lactam's function?

Target's PBP- binds there instead, causes NAG/NAM to fall apart --> breaks cell wall

2

What are the subclasses of B-lactam?

Penicillins
Cepharlosporins
Carbapenems
Monobactam

3

How do bugs become resistant?
(6 Ps)

Penetration – PCN poorly penetrate into intracellular
Bacteria hide in this compartment (i.e. Rickettsia and Legionella)
Porins – “sieving” system prevent PCN to get into periplasmic space
Some G(-) – E. Coli, Proteus M, Salmonella, and Shigella
Pumps – Efflux pump – prevent accumulation
Pseudomonas aeruginosa
Penicillinases (beta-lactamase) – G+ and G-
PBPs – mutated – not binding to penicillins
Peptidoglycan – Do not make peptidoglycan PCN ineffective (i.e. Mycoplasma, and Chlamydia)

4

What are the natural PCN meds on the market? Route?

PCN-G IV
PCN-V PO

5

What is the mechanism of anti-staph penicillins?

Bulky side chain prevent binding to beta-lactamases

6

What are examples of anti-staph PCNs?

Nafcillin, Oxacillin, and Dicloxacillin
Methicillin- no longer available

7

What bugs do anti-staph penicillins treat?

S. aureus, S. epidermidis
BUT NOT MRSA/MRSE

8

Are anti-staph penicillins useful for streptococci or enterococci?

No

9

What is the mechanism of aminopenicillins?

Amino group-> increase hydophilicity
Interferes with NAG/NAM

10

What bugs are targets of aminopenicillins?

E coli
P mirablis
Shigella

11

How does resistance to aminopenicillins form?

Drug is susceptible to beta-lactamse
Bugs with this modification defeat med

12

What are 2 examples of aminopenicillins?

Amoxicillin, ampicillin

13

What is the mechanism of aminopenicillins and b-lactamase inhibitors?

Inhibitors mimic penicillin --> bind to beta-lactamases --> enzyme inactivation
Then interferes with NAG/NAM

14

What are examples of aminopenicillins and b-lactamase inhibitors?

Ampicillin + Sulbactam (Unasyn) – IV
Amoxicillin + Clavulanate (Augmentin) – PO

15

What is the mechanism of extended-spectrum PCN?

Polar side chain allows greater penetration into G- bacteria
More resistant to G- beta-lactamases than aminopenicillins

16

What coverage do you get wth extended-spectrum PCN?

More active against G- bacilli including Pseudomonas
Have modest activity against anaerobes
Still susceptible to beta-lactamases of staph

17

What is the fullest potential of PCN?

Extended spectrum penicillin + beta-lactamase inhibitors

18

What are examples of extended-spectrum PCN?

Piperacillin + tazobactam (Zosyn)- broader
Ticarcillin + clavunate (Timentin)

19

What is the coverage of extended-spectrum PCN (e.g. zosyn)

Cover staph, aerobic G-, almost all anaerobic (except C. diff.)

20

What are the toxicities of PCN?

N/V/D
Drug fever, rash
Hepatotoxicity
Neurologic toxicity
Urticaria
Angioedema

21

What is the coverage of antistaph PCN?

cover G+, but no G- activity

22

What is the coverage of natural PCN?
Bugs?

G+ plus few G- activity (i.e. N. meningitidis, H. influenza)

23

What is the coverage of Amino PCN? Bugs?

G+ plus H. influenza, E. Coli, N. meningitidis, P. mirabilis, S. enterica, Shigella…

24

What is the coverage of ES-PCN? Bugs?

G+ plus H. influenza, E. Coli, N. meningitidis, P. mirabilis, S. enterica, Shigella, AND PSEUDOMONAS

25

What is the coverage of ES-PCN w/ b-lactamase inhibitor? Bugs?

Broadest, cover most enteric G- bacilli
PSUDOMONAS