Pharm 747 Exam 1 Flashcards
Describe the basic Mechanism of Action for B-Lactam Antiobiotics
B-lactam antibiotics are bactericidal, and act by inhibiting the synthesis of the peptidoglycan layer of bacterial cell walls.
Why is the final transpeptidation step in biosynthesis of peptidoglycan a critical drug target step?
It is facilitated by transpeptidases (PBPs) that are inhibited by the B-Lactams.
What are B-Lactam antibiotics analogs of in normal peptidoglycan synthesis?
the D-alanyl-Dalanine terminal amino acid residue that is the precursor for NAM/NAG peptide subunits of peptidoglycan layer
Why is the structural similarity between B-lactam antibiotics and the D-alanyl-D-alanine important?
B-lactam replaces the D-alanyl-D-alanine and inhibits the active site of PBPs
How do B-Lactam antibiotics act upon PBP?
They irreversibly bind to the Serine on the PBP active site, which prevents the final crosslinking (transpeptidation) of the peptidoglycan layer and disrupts the bacterial cell wall biosynthesis.
How can bacterium disrupt B-lactam antiobiotics?
By hydrolysis of B-lactam ring by B-lactamase or penicillinase, which will break open the ring and render the drug ineffective.
How can Bacterium ignore B-Lactam antibiotics?
They can possess altered PBPs which do not allow B-lactams to bind effectively.
where are transpeptidase enzymes found within gram positive and negative bacterium?
They are located along the exterior of the cytoplasmic membrane (+)
They are located in the periplasmic space (-)
What is the general structure of Penicillins?
6-aminopenicillanic Acid (6-APA) and a azetidinone 4-sided ring
What is the general structure of Cephalosporins?
7-amino Cephalosporanic Acid (7-ACA) and a free carboxyl on C4
Benzylpenicillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
Natual Penicillin Penicillin G IV administration Gram (+) Hydrolyzed by B-lactamase
Phenoxymethylpenicillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
Penicillin V
Oral administration
Gram (+)
Hydrolyzed by B-lactamase
Methicillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
B-Lactmase Resistant strain Staphcillin IV administration gram (+) stable against B-lactamase
Nafcillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
B-Lactamase resistant strain Unipen Oral Administration Gram (+) Stable against B-lactamase
Oxacillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
B-lactamase resistant/Isoxazoyl Prostaphlin (X1, X2 = H) Oral Administration Gram (+) stable against B-Lactamase
Cloxacillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
B-lactamase resistant/Isoxazoyl Tegopen (X1 = CL, X2 = H) Oral administration Gram (+) Stable against
Dicloxacillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
B-lactamase resistant/isoxazoyl Dynapen (X1 , X2 = Cl) Oral Administration gram (+) Stable against B-lactamase
Ampicillin/Bacampicillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
Aminopenicillin Polycillin Oral administration Gram (+), small gram (-) Hydrolyzed
Amoxicillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
Aminopenicillin Amoxil Oral administration gram (+), small gram (-) hydrolyzed
Carbenicillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
Carboxypenicillin Geopen Oral and IV administration Gram (+) and Gram (-) hydrolyzed
Ticarcillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
Carboxypenicillin Ticar IV administration Gram (+) and Gram (-) Hydrolyzed
Pipericillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
Acylureidopenicillin Piperacil IV administration Gram (+) and (-) hydrolyzed
Azlocillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
Acylureidopenicillin Azlin IV administration Gram (+) (-) hydrolyzed
Mezlocillin
Class, Brand, PO or IV, +/- , B-lactamase resistant
Acylureidopenicillin Mezlin IV administration Gram (+) (-) hydrolyzed
