Comparative in vitro activity of three aminoglycosidic antibiotics: BB-K8, kanamycin, and gentamicin

Kanamycin, BB-K8, and gentamicin were tested in parallel against 1,037 bacterial strains isolated from clinical material. The activity of BB-K8 at 20 mug/ml was comparable to that of gentamicin at 8 mug/ml against Pseudomonas aeruginosa and against Enterobacteriaceae, with the exception of gentamicin-resistant strains of Proteus rettgeri and Providencia stuartii, in which case the activities of BB-K8 and kanamycin were the same. BB-K8 exhibited little or no activity against streptococci. The activity of BB-K8 was affected by pH and inoculum size. A regression graph for inhibition data with a 10-mug disk of BB-K8 was developed, and synergistic activity of penicillin and BB-K8 against Streptococcus faecalis was tested.