In vitro activity of netilmicin and cefotaxime compared to that of other aminoglycosides.

In vitro activity of netilmicin, cefotaxime, amikacin, dibekacin, gentamicin and tobramicin was compared against clinical isolates in Antibiotic Medium 3 at pH 7.1 and human plasma water at pH 7.8. Except against Pseudomonas aeruginosa the aminoglycosides were generally more active in plasma water than in broth. Against P. aeruginosa higher concentrations were required to inhibit or kill the strain in the plasma water. Cefotaxime was not tested against these organisms. Against E. coli, K. pneumoniae and Proteus species cefotaxime was found to be more active than the aminoglucosides, both in broth and plasma water. Its activity against Staph. aureus was markedly less than that of the aminoglycosides. Tobramicin showed a higher activity in plasma water only against Proteus species.