Antimicrobial Therapy 2 Flashcards
What is the MOA for Beta-lactam antibiotics?
Blocks the transpeptidation of PG; Targets PBP on inner surface of cell wall; Osmotic fragility and cell lysis
What are the classes of Beta-lactams?
- Penicillins
- Cephalosporins
- Carbapenems
- Monobactams
What are the Pharmacokinetics of Beta-lactams?
Bactericidal, Time dependent killing
What are the side effects of Beta-lactams?
Rash, diarrhea, vaginitis
Describe Beta-lactam resistance
- Beta lactamase
- ESBLs
- Mutations to binding site on PBPs(MRSA)
- Impaired penetration and Efflux pumps
How do we overcome Beta-lactamases?
Clavulanic acid
What are the pharmacokinetics of Penicillin?
Widely distrubuted in most tissues except the prostate; Renally cleared
Specific side effects of Penicillins?
- Sodium or Potassium overload with IV
- Beta-lactamase inhibitors increase diarrhea
- Ampicillin/Amoxicillin increase risk of rash if concurrent viral infection
What are the allergies associated with Penicillins?
- Hypersensitivity reaction
- Serum sicknes
- Seizures in patients with renal failure.
- Cross reactivity to all penicillins and beta-lactams except Monobactam and aztreonam.
What is the MOA of cephalosporins?
In addition to its Beta-lactam MOA, it also INCOPORATES itself into the cell wall once bound to PBP.
What side effects are specific to cephalosporins?
- Enterocolitis
- Cefotetan Can block alcohol metabolism by inhibiting aldehyde dehydrogenase
- Ceftriaxone causes biliary sludging (Bilirubin)
Are cephalosporins vulnerable to beta-lactamases?
NO; Their structure prevents beta-lactamase enzymatic destruction. Extended spectrum antibiotic
Discuss resistance to cephalosporins?
- ESBLs; ESBLs do NOT affect cefotetan or Carbapenems.
Describe First generation of cephalosporins
First generation cephalosporins cant penetrate the CNS good penetration into urine.
Describe Second generation cephalosporins
Poor CNS penetration, Cefotetan maintains activity against ESBL-producing organisms; No PSA activity.