Chapter 71: Antibiotics That Weaken the Cell Wall: PCN

Question 1

beta lactam antibiotics

Answer 1

The first, most diverse, and most commonly used Broad class of AB that contain a beta- lactam ring in molecular structure for this type of AB. Hence name. ​

Includes PCN​

Mechanism of Action: BL inhibits bacterial cell wall synthesis in the bacterial organism. ​

Bacteria have developed resistance to B Lactam AB by making Beta-lactamase Enzyme. ​

So BL AB are often paired with a BL inhibitor.​

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Question 2

types of BL AB

Answer 2

PCN, cephalosporins, monobactam, carbapenems

Question 3

Penicillin G (IV/IM) or V (PO)

Answer 3

tx gram + bacteria only

tx all streptococci, meningococci, most gram + anaerobes

min activity for staphylococci

Question 4

Penicillinase

Answer 4

Resistant PCN​

*** Every single Staph Aureus has this enzyme​

Question 5

Semisynthetic PCN

Answer 5

Methicillin​
Oxacillin​
Nafcillin (Used for MSSA)​

enhanced activity against staph -not MRSA

Question 6

MRSA

Answer 6

Genetic mutation occurs. Doesn’t allow any PCN to bind to staph aureus bacteria​

MRSA (methicillin resistant staff aureus: virulent Gram +)

Question 7

extended-spectrum PCN

Answer 7

Amoxicillin (PO)​ and Ampicillin(IV)​

PCN invented to include gram negative coverage. covers G+ cocci and some G- bacilli

amp uses: Increased GN spectrum (Used in URTIs and Otitis Media)​

Question 8

PCN + Beta Lactamase inhibitors

Answer 8

Beta lactamase was formed & new AB became resistant. So, Beta lactamase inhibitor was added to PCN. not all beta lactamses are inhibited.

Easy Gram –​
Augmentin (Amoxicillin/Clavulanic Acid)​
Unasyn (Ampicillin/Sulbactam)​

Hard Gram - Pseudomonas: Virulent Gram -​
Zosyn (Piperacillin- Tazobactam)​
Timentin (Ticarcillin-clavulanate)​

Question 9

known issues with PCNs

Answer 9

resistance (BL and others), allergic rxn, cross-hypersensitivity (1-3% with cephalosporins)

Question 10

therapeutic goals of PCN

Answer 10

Treatment of Bacterial Infections​

Question 11

baseline data for PCN

Answer 11

Samples for microbiologic culture to identify the infecting organism​

Question 12

monitoring for PCN

Answer 12

Renal Impairment can cause PCNs to accumulate to toxic levels. Monitor function in patients in renal disease​

Question 13

identifying high risk pt for PCN

Answer 13

PCNs should be used with extreme caution in patients with a history of severe allergic reactions to PCNs cephalosporins or carbapenems.​

Question 14

evaluating therapeutic effects of PCN

Answer 14

Monitor for reduction in bacterial symptoms: fever edema, pain, inflammation​

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Question 15

min ADR for PCN

Answer 15

For patients with prior allergic responses, a skin test may be ordered to assess current allergy status.