Use of aminoglycosides in immunocompromised patients

For much of the last decade, combination therapy with aminoglycosides has been accepted as the therapeutic approach of choice in immunocompromised hosts. Improved clinical results have also correlated with the presence of synergistic interactions between the aminoglycoside and beta-lactam components of a regimen. Differences between the aminoglycosides and beta-lactam agents remain a subject of controversy. Studies at the University of California, Los Angeles, Medical Center suggest that amikacin interacts more frequently in a synergistic manner with beta-lactams than do alternative aminoglycosides. Amikacin has been used experimentally and (following licensure) without reservation at the University of California, Los Angeles, Medical Center since 1973. Almost 100 blood isolates of both Pseudomonas aeruginosa and Klebsiella pneumoniae collected during the last 12 years have been retested, and no evidence of increased aminoglycoside resistance was found. A relatively new development is interest in empiric therapeutic regimens that employ two beta-lactam agents. In a large, recently completed study, less satisfactory results were observed in P. aeruginosa infections treated with the "double beta-lactam" than in those treated with the regimen containing amikacin; furthermore, nephrotoxicity and eighth nerve damage occurred no more commonly in the group receiving amikacin than in recipients of the double beta-lactam regimen.