[Antibacterial activities of isepamicin against fresh clinical isolates of gram-negative bacilli].

To investigate antibacterial activities of isepamicin (ISP), MICs of ISP as well as other aminoglycosides (AGs) were determined against many strains of Gram-negative bacilli that were clinically isolated in 1993. 1. No ISP-resistant strains were observed among isolates of Escherichia coli, Citrobacter diversus, Klebsiella spp., Enterobacter spp. or Proteus mirabilis. 2. ISP-resistant strains were observed among isolates of Citrobacter freundii, Serratia spp., Proteus vulgaris, Morganella morganii, Providencia spp. and Pseudomonas aeruginosa. The frequency of resistant strains in each species, however, was lower for ISP than other AGs. 3. When MIC90s were compared, antibacterial activities of ISP determined in this study were quite similar to those determined during the drug's development period (1980's) in Japan, suggesting no increase in the number of ISP-resistant strains over the years. 4. The number of clinically isolated Gram-negative bacilli resistant to multiple drugs are increasing in from year to year Japan. Our results in this study suggest that antibacterial activities of ISP may be potent enough against such Gram-negative bacilli resistant to multiple drugs.