Table 3.: Bacteriostatic Interactions Between Ampicillin Plus Ceftriaxone or Ertapenem Against Five Isolates of Enterococcus faecalis Highly Resistant to Aminoglycosides Using the Double Disk Diffusion and the in Broth MIC Methods

Disk Diffusion Synergism MIC (mg/l)
Strain A C E A+C A+E A+Ca A+E b
2557 4 >256 32 - - 2 2
2648 4 >256 64 - - 2 2
2927 1 >256 32 ++ - 2 2
2929 1 >256 16 ++ - 0.5 0.5
2980 2 >256 16 ++ - 2 2

A, ampicillin; C, ceftriaxone; E, ertapenem.
a, MIC of ampicillin in Muller Hinton Broth with a fixed ceftriaxone concentration (10 mg/l).
b, MIC of ampicillin in Muller Hinton Broth with a fixed ertapenem concentration (2 mg/l).