Comparison of the in vitro activities of BB-K8 and three other aminoglycosides against 215 strains of Pseudomonas and Enterobacteriaceae with variable sensitivity to kanamycin and gentamicin.

215 gram-negative bacilli isolated from clinical materials were tested in vitro against BB-K8 by means of disc diffusion and agar dilution tests; the strains included 40 isolates resistant to gentamicin. Approximately 90% of the strains were inhibited by 3.12 mug/ml or less BB-K8. This antibiotic exhibited a comparable activity, although somewhat inferior, to that of gentamicin, against organisms sensitive to gentamicin. It was considrably more active than gentamicin, and comparable to tobramycin, against the isolates of Klebsiella-Enterobacter-Serratia spp. resistant to gentamicin, but less active than tobramycin against 11 strains of Pseudomonas resistant to gentamicin.