Comparative antibacterial effects of amoxycillin, amoxycillin/clavulanic acid and cefotaxime against Enterobacteriaceae as determined by turbidimetry, morphology and viable count.

Cefotaxime has extremely low MIC values in comparison with amoxycillin against Enterobacteriaceae, but studies of antibacterial activity using turbidimetric and viable count methods show no advantage for cefotaxime. Superior rates of killing have been demonstrated for amoxycillin and amoxycillin/clavulanic acid using both constant antibiotic concentrations and changing concentrations to simulate conditions in vivo. Slow bactericidal activity was seen with cefotaxime even at levels greatly in excess of the MIC and could be correlated with filament formation by this compound over a wide range of concentrations.