Aminoglycoside is a medicinal and bacteriologic category of traditional Gram-negative antibacterial therapeutic agents that inhibit protein synthesis and contain as a portion of the molecule an amino-modified glycoside (sugar); the term can also refer more generally to any organic molecule that contains aminosugar substructures. Aminoglycoside antibiotics display bactericidal activity against gram-negative aerobes and some anaerobic bacilli where resistance has not yet arisen, but generally not against Gram-positive and anaerobic Gram-negative bacteria. They include the first-in-class aminoglycoside antibiotic streptomycin (images at right) derived from Streptomyces griseus, the earliest modern agent used against tuberculosis, and an example that lacks the common 2-deoxystreptamine moiety (image right, below) present in many other class members. Other examples include the deoxystreptamine-containing agents kanamycin, tobramycin, gentamicin, and neomycin (see below).
Aminoglycosides that are derived from bacteria of the Streptomyces genus are named with the suffix mycin, whereas those that are derived from Micromonospora are named with the suffix micin. However, this nomenclature system is not specific for aminoglycosides, and so appearance of this set of suffixes does not imply common mechanism of action. (For instance, vancomycin, a glycopeptide antibiotic, and erythromycin, a macrolide antibiotic produced by Saccharopolyspora erythraea, along with its synthetic derivatives clarithromycin and azithromycin, all share the suffixes but have notably different mechanisms of action.)