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Thread: A general and brief description for mechanisms of antibacterial drugs

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    Default A general and brief description for mechanisms of antibacterial drugs

    1.Cell wall synthesis

    Penicillins, Cephalosporins, Carbapenems, Monobactams (beta-lactams, targeting at penicillin-binding proteins/transpeptidase enzymes, usually highly bactericidal),

    and

    such as vancomycin, teicoplanin, telavancin, and bacitracin (non-beta-lactams, targeting at terminal amino acids of the peptide side chains, which inhibits assembly of the linear peptidoglycan molecule, all bactericidal).

    2.Protein synthesis

    Aminoglycosides (targeting at bacterial ribosomes [irreversible bingding], and eukaryotic ribosomes are resistant to aminoglycosides and they are not actively transported into eukaryotic cells [so ineffectiveness against intracellular bacteria, for detail here http://forum.tomhsiung.com/pharmacy-...7.html#post847], rapid bactericidal)

    Tetracyclines (targeting at 30S ribosomal subunit to block attachment of ammoniacal-tRNA to the acceptor site on the mRNA ribosome complex [reversible bingding], bacteriostatic instead of bactericidal),

    Chloramphenicol (targeting at 50S ribosomal subunit and blocking the action of peptide transferase, reversible, bacteriostatic instead of bactericidal),

    Macrolides (targeting at 50S subunit of ribosomal, bacteriostatic),

    Lincosamides (targeting at similar with macrocodes,bacteriostatic),

    Oxazolidinones (binding to bacterial 50S ribosome, bacteriostatic),

    and

    Streptogramins, two drugs (quinupristin and dalfopristin) that binding to two different ribosomal sites (targeting at 50S bacterial ribosome [two different sites], single drug - bacteriostatic, two drugs - bactericidal).

    3.Nucleic acid synthesis

    Fluoroquinolones (bactericidal) including ciprofloxacin, levofloxacin, gemifloxacin, and moxifloxacin. They are target at DNA gyros and topoisomerase IV, the enzymes responsible for nicking, supercoiling, and selling bacterial DNA during replication. Binding to two enzymes reduces the chance a single mutation can lead to resistances.

    Rifamycins (target at beta-subunit of DNA-dependent RNA polymerase so preventing the initiation of RNA synthesis, bactericidal)

    4.Folate biosynthesis (selective toxicity)

    Sulfonamides (as a analogs of PABA [substrate], target at dihydropteroate sythetase, which catalyses the initial stage of folate synthesis, bacteriostatic)

    Trimethoprim-Sulfamethoxazole/TMP-SMX (trimethoprim is targeting at dihydrofolate reductase, which catalyses the conversion of folate to its reduced active coenzyme form, synergistic bacteriostatic or bactericidal)

    5.Cell membrane integrity

    Polymyxin B and colistin (both target at cell membranes of susceptible, enhancing the permeability of the cell membranes, bactericidal, resistance to both rarely develops)

    Daptomycin (target at cell membranes, bactericidal)

    6.Others

    Metronidazole (required anaerobic conditions to reduce the nitro group of the agent, then the reduced products induces breaks of DNA strands, bactericidal)

    The End
    Last edited by admin; Mon 1st December '14 at 9:25pm.
    Clinical Pharmacy Specialist - Hematology

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