Actions of Antibiotics Flashcards
Antimicrobial Agents can interfere with?
Cell wall synthesis, protein (ribosomes) synthesis, nucleic acid synthesis, plasma membrane integrity, folate synthesis and more
Antibiotics of cell wall synthesis are
Beta Lactams, Vancomycin (glycopeptides) , Fosfomycin and Daptomycin
What are the 4 classes of Beta Lactams?
Penicillin, Cephalosporin, Carbapenems, and Monobactams
Antibiotics of cell membrane synthesis are
polymyxins, Bacitracin, Daptomycin, anti-fungals and Colistin (last resort antibiotic for gram negative organisms)
Antibiotics of protein synthesis are
Tetracyclines, aminoglycosides, macrolides,lincosamides (clindamycin), linezolid, chloramphenicol, streptogramins
Antibiotics of nucleic acid synthesis are
Quinolones and Metronidazole (DNA gyrase), and Rifampin and Bacitracin and Mupirocin (RNA polymerase)
Antibiotics of Folate synthesis and that interfere with Metbolic pathways are
Sulfonamides, Trimethoprim; used in combination, Trimethoprim and Sulfomethoxazole (Bactrim)
what do we know about beta lactam antibiotics
they are the most commonly prescribed drugs; all have the beta lactam ring. they are non-toxic and relatively cheap
how many classes of penicillin are there?
Six classes of penicillin
how many generations of cephalosporins?
4 generations of cephalosporin
what are penicillin binding proteins?
PBPs are enzymes that catalyze the final cross linking reactions of peptidoglycan synthesis; used to identify MRSA
how do the B-lactam antibiotics work?
antibiotics bind to the transpeptidase enzyme that cross links the peptidoglycan strands. irreversibly inhibits the transpeptidase enzyme bacterial cell wall synthesis is inhibited
what do we know about the carbapenems?
these are beta-Lactam antibiotics which have a broad spectrum of action, they are a more advanced form of beta-Lactams and are highly resistant to enzymes
how do glycopeptides work?
they will bind to the D-alanly-Dalanine residue, PBPs can no longer bind to these residues since it is blocked. Vancomycin is the main example, it is effective only against gram positive organisms
what do we know about tetracylclines?
broad spectrum antibiotic, resistance to this antibiotic is common so use is limited
how do we manage the patient when giving aminoglycoside drugs?
they are given aminoglycosides and have to be monitored, are renal and oto-toxic at high doses
antibiotics of inhibition of membrane synthesis
polymyxin B, Colistin and Daptomycin
antibiotics that inhibit the folate pathway
sulfonamides, Trimethoprim, Trimethoprim/Sulfamethoxazole, Dapsome (bactericidal)
why does folate make a good selective target?
it does because folic acid is essential to synthesize adenine and thymine, and humans do not synthesize it.
antibiotics of inhibition of nucleic acid synthesis
fluoroquinolones, rifampin and bacitracin
empiric therapy
is useful for deciding what organism a person might be most susceptible to, and figuring out what antibiotic could handle that organisms
