Antibiotics Flashcards
Penicillin
Cell wall inhibitors: contain b-lactam ring. Inhibit peptidoglycan crosslinking
Quinolone
Inhibit nucleic acid synthesis: inhibits topoisomerase II ligase domain. This coupled with contain topoisomerase leads to DNA framentation in nuclease activity.
Gram (-) target DNA gyrase.
Gram (+) target topoisomerase IV
Cycloserine
Cell wall inhibitor: Inhibits alanine racemase (produces D-alanine) and D-alanine ligase (joins two residues of D-alanine)
Aminoglycosides
Protein synthesis inhibitor: Causes 30S ribosomes to prematurely release peptides
Tetracycline
Protein synthesis inhibitor: Inhibits the elongation of polypeptides at 30S ribosomes
Sulfonamides
Antimetabolites: Competitive inhibitor of dihydropteroate synthase and disrupts folic acid synthesis.
Ethambutol
Cell wall inhibitor: Inhibits arabinogalactin synthesis which leads to an increased permeability of the cell wall
Isoniazid
Cell wall inhibitor: Inhibits the synthesis of mycolic acids
Rifampin
Nucleic acid synthesis inhibitor: Prevents transcription by binding DNA dependent RNA polymerase.
Ethionamide
Cell wall inhibitor: Inhibits the synthesis of mycolic acids
Glycylcycline
Protein synthesis inhibitor: Prevents initiation of protein synthesis at 30S ribosomes by binding to it
Macrolides
Protein synthesis inhibitor: Prevents the elongation of polypeptides at 50S ribosomes.
Daptomycin
Cell wall inhibitor: Causes the cytoplasmic membrane to depolarize rapidly causing a huge efflux of ions which leads to inhibition of protein, DNA, and RNA synthesis
Bacitrin
Cell wall inhibitor: Prevents the transportation of NAG-NAM units outside
Oxalidinone
Protein synthesis inhibitor: Prevents the initiation of protein synthesis at 50S ribosomes.
Vancomycin
Cell wall inhibitor: Prevents crosslinking and formation of NAG-NAM peptides
Ketolides
Protein synthesis inhibitor: Prevents the initiation of protein synthesis at 50S ribosomes
Polymyxin
Cell wall inhibitor: The hydrophobic tail penetrates both the outter and inner membranes of gram negative bacteria and damages it. It’s actions are detergent-like.
Cephalosporin
Cell wall inhibitor: Prevents peptidoglycan crosslinking
Rifabutin
Nucleic acid synthesis inhibitor: Blocks DNA-dependent RNA-polymerase. Effective against gram +, -, and mycobacteria.
Metronidozole
Nucleic acid synthesis inhibitor: When it is reduced by anaerobes or protozoa to nitroso intermediates, it will form sulfinamides and thioether linkages with cystein-bearing enzymes. This deactivates these critical enzymes
Cephamycin
Cell wall inhibitor: Prevents crosslinking of peptidoglycan
Carbapenem
Cell wall inhibitor: Prevents crosslinking of peptidoglycan
Dapsome
Antimetabolites: Competitively competes with para-aminobenzoate for the active site of dihydropteroate synthase.
Clindamycin
Protein synthesis inhibitor: Prevents the enlongation of peptides at 50S ribosomes.
Usually used to treat infections with anaerobic bacteria and also malaria.
Trimethoprim
Antimetabolite: a pyrimidine inhibitor of dihydrofolate reductase and disrupts folic acid synthesis
Streptogramin
Protein synthesis inhibitor: Prevents the elongation of peptides at 50S ribosomes.
Effective against vancomysin-resistant enterococcus and staphylococcus aureus.
Monobactum
Cell wall inhibitor: Prevents crosslinking of peptidoglycan
Synergistic combination
B-lactam drugs (penicillin, cephalosporin, cephamycin, carbapenem, and monobactam) with B-lactamase inhibitors (tazobactam, clavulanic acid, and sulbactam) enhance the effects of protein synthesis inhibitor (e.g. aminoglycosides)
Antagonistic combination
Certain drugs like chlortetracycline can induce B-lactamase effects rendering penicillin less effective
Bactericidal (not bacteriostatic) antiobiotics
Penicillin, cephalosporin, aminoglycoside, vancomysin, fluoroquinolone, metronidazol
