Flashcards in 07_Antibiotics Chart_E18 and E19_Spencer - Sheet1 Deck (28)
Plasmid-coded, trimethoprim-resistant dihydrofolate reductase.
Hydrolysis of ß-lactam ring by ß-lactamase enzyme; decreased Cephalosporins permeability of bacteria to the antibiotic; altered penicillin binding proteins.
Altered penicillin binding proteins (not in ß-lactamase). (a ß-lactamase-resistant penicillin).
Enzymatic modification of drug by plasmid-coded enzyme; decreased permeability of bacteria to the antibiotic; mutation alters site to which antibiotic normally binds (e.g. S12 ribosomal protein for streptomycin).
Interference with transport of drug into cell.
Detoxification of drug by acetylation of hydroxyl.
Enzymatic methylation of 23S ribosomal RNA.
Ciprofloxacin & Rifampin resistance
Altered target enzymes (gyrase, RNAP)
Alteration of cell wall precursor target.
Antimetabolites (sulfonamides, trimethoprim)
Inhibit synthesis of dihydrofolate, ultimately nucleic acid synthesis.
inhibits thmidylate synthetase and ultimately DNA synthesis
Inhibits synthesis of mycolic acid (specific for Mycobacteria)
b-Lactams, penicillins, cephalosporins
Interfere with cell wall biosynthesis. Inhibition of transpeptidation weakens cell wall. Autolytic enzymes of bacteria then promote lysis.
Cycloserine, bacitracin, glycopeptides, vancomycin, teichoplanin, caspofungin
Interfere with cell wall biosynthesis.
Polymyxins, polyenes, nystatin, amphotericin B, daptomycin
Disrupt membrane integrity.
Inhibit protein synthesis by binding to a specific protein of 30S ribosomal subunit.
Aminoglycosides (gentamicin, kanamycin, neomycin, amikacin, tobramycin)
Bind to 30S ribosomal subunit at multiple sites. Inhibit protein synthesis.
Block protein synthesis by inhibiting binding of amino-acyl t-RNA to 30S subunit.
Erythromycin, azithromycin, clindamycin, chloramphenicol
Bind to 50S ribosomal subunit. Inhibit protein synthesis at chain elongation step.
Bind rRNA on both ribosomal subunits (new)
Streptogramins (dalfopristin, quinupristin)
Bind to 50S ribosomal subunit (new)
Binds isoleucyl tRNA synthetase, preventing charging of Ile-tRNA and thus affecting protein synthesis.
Inhibit bacterial DNA gyrase.
Binds to bacterial RNA polymerase and blocks transcription.
Azoles (fluconazole, ketoconazole)
Inhibit ergosterol synthesis.