Exam 2: Inhibitor Of Cell Wall Synthesis I Flashcards
What is the composition of peptidoglycan?
- A backbone of alternating sugars, NAGs and NAMs
- A chain of 4 amino acids links to NAM
- A peptide bridge that cross links the tetrapeptide chains
What is the target of all Beta Lactam antibiotics?
Penicillin binding proteins
What is the enzyme that facilitates transglycosylation and transpeptidation?
Penicillin binding protein
What causes cell death from antibiotics that inhibit cell wall synthesis?
Osmotic lysis
What is transglycosylation?
Joining of the NAG and NAMs together
What is transpeptidation?
Forming cross links of pentapeptides
What are the 5 areas that inhibitors of cell wall synthesis target?
1) transglycosylation
2) transpeptidation
3) NAG reduction to NAM
4) transport across the inner membrane
5) Amino acid mimicry
What are the natural penicillins?
Penicillin B
Penicillin V
Benzathine penicillin
Proclaine Penicillin G
What are the penicillinase resistant penicillins?
Nafcillin
Dicloxicillin
Oxacillin
*Methicillin
What are the extended spectrum pencillins?
Ampicillin
Amoxicillin
What are the antipseudomonal penicillins?
Piperacillin
Ticarcillin
What does pencillinase do?
It binds to the beta-lactam ring and hydrolyzes the ring, inactivating the antibiotic
What has the highest antibacterial activity against certain G+ bacteria, including anaerobic bacteria?
Natural penicillins
What are natural penicillins inactivated by?
B-lactamase (penicillinase)
How are natural penicillins elimated from the body?
Active transport in the kidney
If an drug is acid resistant, what should the route of administration be?
PO
Do natural penicillins have antipseudomonal activity?
No.
What type of bacteria are penicillinase resistant pencillins effective against?
G positive, but lower activity when compared to natural penicillins.
-No antipseudomonal activity
How are penicillinase resistant penicillins excreted from the body?
Hepatic metabolism and renal excretion
What is the mechanism of resistance for MRSA?
It produces an alternate PBP, which decreases the affinity of B-lactam antibiotics for PBPs
Can B-lactams be used to treat MRSA?
No, except for ceftaroline
What kind of bacterial do extended spectrum penicillins work on?
- Extended G- coverage (E. Coli, salmonella, shigella, H influenzae).
- Lower G+ coverage
- No antipseudomonal activity
What is the drug of choice for lysteria infections?
Extended spectrum penicillins (Ampicillin, Amoxicillin)
What are the 4 types of B-lactam antibiotics?
Penicillins, cephalosporins, monobactrams, and carbapenems
Are extended spectrum penicillins acid resistant? What does this mean?
Yes, they are taken orally
What ampicillin rash?
A generalized dull maculopapular rash generally appearing 3-14 days after the start of therapy. This is not an allergic or hypersensitivity reaction and patient does not need to be taken off of the ampicillin
What bacteria do antipseudomonal penicillins target?
Major use is for pseudomonas aeruginosa and acinetobacter (lethal), but also targets bacteria covered by extended spectrum penicillins plus some additional enteric gram negative bacilli.
How are antipseudomonal penicillins excreted?
Renal excretion
Are antipseudomonal penicillins acid resistant? What does this mean?
No they are acid sensitive, they must be taken parenterally
When treating P. Aeruginosa with an antipseudomonal penicillin, what else should be given to avoid resistance?
Aminoglycosides
What does the addition of a beta lactamase inhibitor do to antibiotics such as ampicillin, amoxicillin, or piperacillin?
It extends the spectrum because it doesn’t let beta lactamase break down the drug
If you have a combination product with a beta lactamase inhibitor, will it work against MRSA?
Nope
What Beta lactamase inhibitor is ampicillin normally paired with?
Sulbactam, which forms Unasyn
What Beta lactamase inhibitor is amoxicillin normally paired with?
Clavulanic acid, which formed augmentin
What Beta lactamase inhibitor is piperacillin normally paired with?
Tazobactam, which forms Zosyn
What Beta lactamase inhibitor is Ticarcillin normally paired with?
Clavulanic acid, which forms Timentin
What are the toxicities that penicillin can have?
- Allergy
- electrolyte imbalance
- GI disturbance
- Superinfection
What are the 5 pharmacokinetic factors of penicillins?
1) good tissue penetration
2) bad CNS penetration
3) mostly renal elimation (except for penicillinase resistant)
4) filtration and tubular excretion
5) Probenecid inhibits renal elimination
What prescriptions are given for H. Pylori (Gram -)?
Bismuth + metronidazole + tetracycline or amoxicillin
What prescriptions are given for lysteria (gram +) species?
Ampicillin and possibly aminoglycosides
How is strep pneumoniae (gram +)treated?
Penicillin
How is strep pyogenes (gram +)treated?
Penicillin and Clindamycin
How is strep agalactiae (gram +) treated?
Penicillin and possible aminoglycosides
How is Viridans strep (gram +)treated?
Penicillin
How is methicillin resistant bacteria (gram +) treated?
Vancomycin
How are the leptospira and treponema species (spirochetes) treated?
Penicillin
How is early Borrelia Burgdorferi treated?
Amoxicillin
What is the DOC for N. Meningitides, S. Pneumoniae, Strep A and B, enterococcus, Actinomyces, Leptospira, and treponema?
Natural penicillins
What is the DOC for Beta lactamase staphylococcus aureus (MSSA)?
Penicillinase resistant pencillins (Nafcillin, Dicloxacillin, Oxacillin)
What is the gold standard antibiotic treatment for G+ infections?
Natural Penicillins
What are the three other antibiotics that are cell wall inhibitors, but not B-lactams?
- Vancomycin
- Bacitracin
- Fosfomycin
