Beta Lactams Flashcards
What is the function of beta lactam drugs?
Bacterial cell wall
What does a beta lactam ring look like?
What is the target enzyme of beta-lactam drugs?
Transpeptidase enzymes (stops peptidoglycan layer synthesis)
What type of bond is the bond between an antibiotic and the active site?
Covalent bond (very strong, makes beta lactams very effective!)
Renders the enzyme inactive
What are the four common pathogens we use beta-lactam drugs for?
- Strep pyogenes (pharynx and skin) - penicillin G
- Strep pneumo (respiratory infections, meningitis, sepsis) - amoxicillin and ampocillin
- Staph aureus (skin and soft tissue) - methicillin
- Pseudomonas aeruginosa (UTI, sepsis) - piperacillin
Are beta lactam drugs bactericidal or bacteriostatic?
Bactericidal
(kills cell due to osmotic rupture)
What are the four classes of penicillins?
- Natural
- Amino-penicillins
- Anti-staphylococcal
- Extended Spectrum
What must you do for treatment if a patient has a penicillin allergy?
Use a drug from a completely different class
What two drugs belong to the natural penicillin class? What routes are they given?
- Penicillin G (IV, IM) (almost unusable due to bacterial resistance)
- Penicillin V (PO)
What can natural penicillins treat?
- Strep pyogenes (throat and skin) (strep throat & impetigo)
- Oral/dental infections (oral anaerobes)
- Syphilis
What helps penicillins not degrade in stomach acid?
Carbon ring
What two drugs belong to the aminopenicillin class?
- Ampicillin (IV)
- Amoxicillin (PO)
What can amino-penicillins treat?
- Common respiratory tract infections (STREP PNUEMO, Moraxella, Haemoophilus)
- UTIs
- Most E. coli strains
- Same things natural penicillins can treat also
What do you not want to treat with amino-penicillins?
MRSA
What three drugs belong to the class anti-staphylococcal penicillins? And what route are they given?
- Methicillin (IV)
- Nafcillin (IV)
- Dicloxacillin (PO)
What can anti-staphylococcal penicillins treat?
- Staph aureus (skin and soft tissue, internal infections)
- MSSA skin infections (never MRSA)
- Surgical skin prophylaxis (ortho pre-op)
Why are anti-staphylococcal penicillins fairly ineffective?
- Staph aureus did not have great susceptibility to penicillin G….therefore anti staph drugs were developed
- Important historically but due to MRSA, they are ineffective