In vitro comparison of synergism between cefamandole and gentamicin or tobramycin by the triple layer agar method with enzymatic inactivation.

A synergistic effect was shown with gentamicin and tobramycin by means of a triple layer agar technique and enzymatic inactivation of cefamandole after only four hours' incubation. When the strain is sensitive to cefamandole and aminoglycosides, synergy is observed against all the strains studied (Staphylococcus aureus, Proteus, Klebsiella, Escherichia coli, Enterobacter, and Haemophilus influenzae). No significant difference was noted between the cefamandole-tobramycin and the cefamandole-gentamicin combinations when the microbial strains were sensitive to the three antibiotics.