Gentamicin C2 together with epimer C2a is a part of the antibiotic of the aminoglycoside group, gentamicin. Gentamicin C2 has a methyl group in the 6′ position. Gentamicin is a broad-spectrum antibiotic that binds to the prokaryotic ribosome, inhibiting protein synthesis in susceptible bacteria. Gentamicin is bactericidal in vitro against Gram-positive and Gram-negative bacteria.

Gentamicin A is a component of the antibiotic gentamicin. This antibiotic is composed by members of the gentamicin C complex (80%) and gentamicin A, B, X, and others (remaining 20%). A review study from 2018 indicated that acute kidney injury was described in 2520 participants receiving gentamicin, which contains gentamicin A. Most of these cases were reversible. Also, a rise in creatinine levels was found in some patients after administration of a single dose of gentamicin.

Sisomicin is a new broad-spectrum aminoglycoside most closely related structurally to gentamicin C1a. In vitro and in experimental infections, sisomicin has been found to be more potent than or nearly as potent as the most active of the other available aminoglycosides. Although susceptible to many (but not all) aminoglycoside-inactivating enzymes, sisomicin is active against many microorganisms that are resistant to other aminoglycosides by nonenzymatic mechanisms. Sisomicin has been shown to interact synergistically with various beta-lactam antibiotics against enterococci, staphylocicci, Enterobacteriaceae, and nonfermentative gram-negative bacilli. The pharmacokinetics and toxicity of sisomicin in humans appear to be similar to those of gentamicin, despite earlier reports of greater acute toxicity in animals. Sisomicin binds to 30s and 50s ribosomal subunits of susceptible bacteria disrupting protein synthesis, thus rendering the bacterial cell membrane defective.

Micronomicin is a new aminoglycosidic antibiotic discovered and developed by Kyowa Hakko Kogyo Co., Ltd. It is produced by Micromonospora sagamiensis var. nonreducans. Investigation of micronomicin performed in 134 research facilities in Japan led to the following results. 1) Micronomicin showed a broad antibacterial spectrum against Gram positive and Gram negative bacteria. 2) In susceptibility tests of clinical isolates, micronomicin was almost similarly active to GM. 3) Bactericidal activity of micronomicin against Pseudomonas aeruginosa and E. coli was higher than those of TOB and DKB. 4) Micronomicin showed a synergistic antibacterial activity against Pseudomonas aeruginosa and E. coli with CBPC and SBPC. 5) The therapeutic activity of micronomicin in mice infected with Pseudomonas aeruginosa and Serratia sp. was in high correlation with in vitro antibacterial activity similarly to that of GM. Micronomicin (sold under the brand names Sagamicin and Luxomicina among others) is an aminoglycoside antibiotic, and like others in its class, binds to the ribosomes of non-resistant cells causing mistranscription of mRNA which fatally inhibits production of essential proteins. Micronomicin sulfate can inhibit bacterial protein synthesis, while destroy the bacterial cell wall. Micronomicin has an antibacterial activity against gram-negative and gram-positive bacteria such as Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Shara, Escherichia coli, etc. Streptococcus pneumoniae and Pneumococcus are sensitive to it, but its activity on anaerobic bacteria and some hemolytic streptococcus is weak.

Gentamicin is an antibiotic of the aminoglycoside group, is derived from the growth of Micromonospora purpurea, an actinomycete. Gentamicin is a complex of three different closely related aminoglycoside sulfates, Gentamicins C1, C2, and C1a that have different patterns of methylation at the 69 position of the ring. Gentamicin C1a is a broad-spectrum antibiotic against Gram-positive and Gram-negative bacteria but may cause ear and kidney damage. Gentamicin C1a binds to the A-site RNA of the 30S bacterial ribosomal subunit. Adverse reactions include adverse renal effects, neurotoxicity (dizziness, vertigo, tinnitus, roaring in the ears, hearing loss, peripheral neuropathy or encephalopathy), respiratory depression, lethargy, confusion, depression, visual disturbances, etc.