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Jawetz, Melnick, & Adelberg's Medical Microbiology, 24e
| Section III. Bacteriology > |
Mechanisms of Action of Antimicrobial Drugs
Sections: Selective Toxicity, Inhibition of Cell Wall Synthesis, Inhibition of Cell Membrane Function, Inhibition of Protein Synthesis, Aminoglycosides, Macrolides, Azalides, Ketolides, Lincomycins, Tetracyclines, Glycylcyclines, Chloramphenicol, Streptogramins, Oxazolidinones, Inhibition of Nucleic Acid Synthesis.
Topics Discussed: 4-aminobenzoic acid; aminoglycosides; antimicrobials; azalides; beta-lactam antibiotics; beta-lactamase; cell membrane transport; cell wall biosynthesis; chloramphenicol; daptomycin; drug toxicity; extended-spectrum beta lactamases; glycylcycline; ionophores; ketolides; lincomycin; macrolides; nucleic acid synthesis inhibitors; oxazolidinones; penicillin resistance; penicillin-binding proteins; polymyxins; protein synthesis inhibitors; pyrimethamine; streptogramins; sulfonamides; sulfonamides and trimethoprim; tetracycline resistance; tetracyclines; trimethoprim.
Excerpt:
"Antimicrobial drugs act
in one of several ways: by selective toxicity, by inhibition of
cell membrane synthesis and function, by inhibition of protein synthesis,
or by inhibition of nucleic acid synthesis.An ideal antimicrobial
agent exhibits selective toxicity, which means that the drug is
harmful to a pathogen without being harmful to the host. Often,
selective toxicity is relative rather than absolute; this implies
that a drug in a concentration tolerated by the host may damage
an infecting microorganism.The mode of action
of streptomycin has been studied far more intensively than that
of other aminoglycosides, but all probably act similarly. The first
step is the attachment of the aminoglycoside to a specific receptor
protein (P 12 in the case of streptomycin) on the 30S subunit of
the microbial ribosome. Second, the aminoglycoside blocks the normal
activity of the "initiation complex" of peptide
formation (mRNA + formyl methionine + tRNA). Third,
the mRNA message is misread on the "recognition region" of
the ribosome; consequently, the wrong amino acid is inserted into
the peptide, resulting in a nonfunctional protein. Fourth, aminoglycoside
attachment..."
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