Amikacin therapy. Use against infections caused by gentamicin- and tobramycin-resistant organisms

Area of Science:

• Infectious Diseases
• Pharmacology
• Microbiology

Background:

• Serious infections caused by Gram-negative organisms resistant to multiple drugs pose a significant clinical challenge.
• Aminoglycosides are crucial for treating such infections, but resistance patterns necessitate evaluating new therapeutic options.

Purpose of the Study:

• To evaluate the efficacy and safety of amikacin sulfate in treating serious infections caused by drug-resistant Gram-negative bacteria.
• To compare the in vitro activity of amikacin against gentamicin and tobramycin for the causative organisms.

Main Methods:

• A retrospective analysis of 24 treatment courses of amikacin sulfate in 25 patients with serious Gram-negative infections.
• In vitro susceptibility testing was performed, determining minimal inhibitory concentrations (MICs) for amikacin, gentamicin, and tobramycin.
• Clinical outcomes and adverse events, including ototoxicity assessed by serial audiometry, were monitored.

Main Results:

• Amikacin sulfate demonstrated an 80% favorable response rate across various infection sites, including urinary tract, pleuropulmonary, and bacteremia.
• The causative organisms, primarily Serratia marcescens and Pseudomonas sp (73% of isolates), showed significantly lower MICs to amikacin (3.6 µg/ml) compared to gentamicin (39 µg/ml) and tobramycin (32 µg/ml).
• Ototoxicity was observed in 3 of 15 patients evaluated by audiometry, highlighting a potential safety concern.

Conclusions:

• Amikacin sulfate is an effective therapeutic option for serious infections caused by multidrug-resistant Gram-negative organisms.
• Its in vitro activity against key pathogens like Serratia and Pseudomonas surpasses that of gentamicin and tobramycin.
• Careful monitoring for ototoxicity is warranted during amikacin sulfate treatment.