Examples of Aminoglycoside Antibiotics
The clinically available aminoglycosides include gentamicin, tobramycin, amikacin, streptomycin, kanamycin, and neomycin. 1
Most Commonly Used Aminoglycosides
Gentamicin is the most frequently prescribed aminoglycoside in clinical practice, particularly in UK neonatal units where it serves as the most commonly used antibiotic. 2
Amikacin demonstrates superior activity against aminoglycoside-resistant organisms and is preferred for general use due to its low resistance potential, high and predictable serum peaks, wide toxic-therapeutic ratio, and convenient q12h dosing schedule. 3
Tobramycin shows comparable efficacy to gentamicin against susceptible organisms and may be less nephrotoxic than gentamicin when combined with beta-lactams. 4, 3
Less Commonly Used Aminoglycosides
Streptomycin has a distinct core ring structure that explains why cross-resistance between streptomycin and other aminoglycosides is uncommon, making it valuable when gentamicin resistance is present. 1
Kanamycin is generally the least active aminoglycoside, with 89% of Pseudomonas aeruginosa strains showing resistance. 5
Neomycin is primarily used for topical or oral administration due to significant systemic toxicity concerns when absorbed. 6
Clinical Context for Selection
For carbapenem-resistant Enterobacteriaceae (CRE) infections, combination therapies containing amikacin or other aminoglycosides are suggested, with CRE isolates in China showing significantly higher susceptibility to amikacin than to gentamicin. 7
For neonatal sepsis, gentamicin is recommended in combination with ampicillin, amoxicillin, or benzylpenicillin as first-choice therapy, with amikacin reserved as a second-choice option. 7
For intra-abdominal infections, aminoglycoside-based regimens include gentamicin, tobramycin, netilmicin, or amikacin, each combined with an antianaerobe agent (clindamycin or metronidazole), though these are not recommended for routine community-acquired infections due to toxicity concerns. 7
Important Resistance Patterns
All Enterococcus faecium are intrinsically resistant to amikacin, kanamycin, netilmicin, and tobramycin. 1
Strains resistant to gentamicin may remain susceptible to streptomycin due to different resistance mechanisms. 1
Amikacin inhibits approximately 88% of gram-negative strains at concentrations ≤4 μg/ml, including those resistant to gentamicin and tobramycin. 8