Beta-Lactams

Question 1

Names of beta-lactamase inhibitors

Drugs used with

Answer 1

clavulanic acid, sublactam, tazobactam
These extend the spectrum of antiobiotics
Used with: Extended Spectrum Penicillins (Amoxicillin and Ampicillin) and Anti-Pseudomonal Penicillins (Piperacillin, ticarcillin, ect.)
Not active against MRSA!

Question 2

Ways bacteria can be resistant to Penicillins (5)

Answer 2

1. Lack a cell wall (mycobacterium)
2. Altered PBP’s (MRSA) - b-lactam loses affinity for the altered PBP
3. Inhibited Transport through the cell membrane
4. Autolytic enzymes are not activated forming tolerance (cell walls need to be in the process of growing using autolytic enzymes for b-lactams to work) - ex: Lysteria
5. Inactivation of peneicillin by bacterial b-lactamase (Penicillinase) an inducible enzyme

Question 3

Toxicity

Answer 3

Allergy (NOT AMPICILLIN RASH)
electrolyte imbalance
GI upset
Superinfections

Question 4

Pharmacokinetics

Answer 4

Good tissue penetration
poor CNS penetration 
mostly renal excretion
filtration and tubular excretion 
probenecid prolongs the action of the drug by prohibiting renal excretion temporarily

Question 5

MOA of beta-lactams

Answer 5

Call Wall Synthesis Inhibition
Prevent Transpeptidation - the crosslinking- of peptidoglycan strands through transpeptidases or PBP’s
-Bacteriocidal
- bacteria uses autolysins in the process of cell growth. In the absence of transpeptidation, peptidoglycan strands are weak and separated. when autolysis are activated, the whole structure falls apart by osmotic lysis
-NEVER PAIR A PENICILLIN WITH A PROTEIN SYNTHESIS INHIBITOR!!

Question 6

Points of peptidoglycan synthesis that can be inhibited by antibiotics

Answer 6

1. Transpeptidation - crosslinking pentapeptides
2. Transglycosylation - joins NAG - NAM
3. Transport across cell membrane
4. Reduction of NAG-NAM
5. amino acid mimicry - pentapeptide chain

Question 7

4 types of beta-lactams

Answer 7

1. Penicillins
2. Cephalosporins
3. Monobactams
4. Carbapenems