Lecture 2 Flashcards
(35 cards)
What is the purpose of a peptidoglycan layer?
Provides structural integrity of cell wall
What is the purpose of a transpeptidase enzyme?
Found in periplasmic space function to crosslink the peptidoglycan chains
What is the MOA of beta-lactams?
Binds to transpeptidase which inhibits peptidoglycan synthesis and causing cell wall to lysis
How do Gram + bacteria build resistance towards the beta-lactams?
Reduced binding affinity to penicillin binding proteins
Production of B-lactamases
Overproduction of penicillin binding proteins
How do Gram - bacteria building resistance towards beta-lactams?
Loss of outer membrane porins
B-lactamases in periplasmic space
Expression of transmembrane efflux pump
What does B-lactamase do?
Breaks the B-lactam ring in penicillin
Converts to penicilloic acid
What is the most common antibiotic prescribed?
Azithromycin and amoxicillin
What are the first line treatments for penicillin?
Strep throat
Syphillis (treponema pallidum)
Cellulitis
Meningitis
What are the cons of penicillin?
Increasing resistance
Useless in presence of b-lactamase
What are the pros of penicillin?
Cheap and relatively safe
What are the antistaphlococcal penicillins?
Dicloxacillin
Oxacillin
Nafcillin
Methicillin (prototype: not used in treatment)
What are antistaphlococcal PCN not effective against?
MRSA infections
What are antistaphlococcal PCN used for?
Skin and soft tissue staphylococcal infections
(staph aureus and staph epidermidis)
What is methicillin only used for?
To identify microbial resistance
What are the aminopenicllins?
Amoxicillin and Ampicillin
What additional coverage does aminopenicillins have over penicillins?
Better gram - coverage
What are the first-line treatment for aminopenicillins?
Ottis media and prophylaxis for endocarditis
What bacteria causes otitis media?
Haemophilus influenzae
Streptococcus pneumoniae
Moraxella catarrhalis
Why would amoxillin be preferred over ampicillin?
PO intake has better absorption
What are aminopenicillins taken with to fight against b-lactamase?
B-lactamase inhibitors
What are advantages of aminopenicillins over natural penicillins?
Higher oral absorption and longer half life
Better penetration of gram- cell wall porins
What are the PCN/B-lactamase inhibitor?
Amoxicillin/Clavulanic acid
Ampicillin/Sulbactam
What coverage does PCN/B-lactamase inhibitor have?
Same as amoxicillin but with better staphylococcus coverage
PCN/B-lactamase inhibitor is a first line treatment for what?
Sinusitis
Pneumonia/COPD exacerbations
