Amikacin in treatment of infections caused by gram-negative bacteria resistant to gentamicin and other aminoglycosides: clinical and bacteriologic results.

Amikacin (250 or 500 mg) was administered intramuscularly twice daily at 12-hr intervals to 34 patients with infections due to various gram-negative bacteria. Usually one or more aggravating factors were present, such as serious underlying pathology or therapy with steroids or immunosuppressants. Clinical isolates from most patients were resistant to gentamicin and other aminoglycosides. The overall response to therapy was excellent in 20 patients; in eight patients clinical response was good, but the organism persisted. Six patients showed some improvement without complete resolution of the infection or eradication of the causative organism. There were no complete clinical or bacteriologic failures. Ototoxicity was not observed in any patient. Levels of blood urea nitrogen and serum creatinine increased in two patients but returned to pretreatment levels within two weeks after therapy. No other adverse reactions were noted. Amikacin may replace gentamicin as initial therapy in serious gram-negative bacillary infections, particularly when resistance to gentamicin is a problem.