IN VITRO ANTIBACTERIAL ACTIVITIES AND CLINICAL EFFECTS ON RESPIRATORY INFECTIOUS DISEASES OF AMIKACIN (BB-K8)

Abstract

Antibacterial activities of amikacin (BB-K8) were examined. Minimum inhibitory concentration (MIC) of amikacin against human tubercle bacilli, strain H37Rv, was 0.39 μg/ml. Six patient strains were inhibited by the drug at the concentrations of 0.09 to 0.39 μg/ml, but none out of 9 patient strains, which were highly resistant to kanamycin, was inhibited by amikacin. Though 8 out of 11 patient strains of Staphylococcus aureus were equally susceptible to amikacin and kanamycin, the remaining 3 strains, highly resistant to kanamycin, were inhibited at the concentrations of 6.25 to 12.5 μg/ml of amikacin. No marked difference in antibacterial activities against E. coli and Klebsiella pneumoniae strains was observed between amikacin and kanamycin. Amikacin inhibited all of 19 patient strains of Pseudomonas aeruginosa at 1.56 to 12.5 μg/ml, but MIC of kanamycin against these strains was 100 μg/ml or more.
Clinical evaluation of amikacin was made in 13 patients with respiratory tract infection and 1 with urinary tract infection. In 2 patients, with primary lung abscess and pyelocystitis respectively, an excellent therapeutic response was obtained. A good response was seen in 5 patients. Six patients with secondary respiratory infectious diseases exhibited no significant therapeutic effect. The response of 1 case was unidentified because of simultaneous administration of sulfobenzyl penicillin.
None of 14 patients treated with amikacin showed any signs of auditory disturbance. Results of kidney and liver function tests revealed values in normal range before and after administration of amikacin.