A study of the influence of cephalosporins on the microbial activity of E. coli by microcalorimetry

The effects of Cefoperazone Sodium(CFZ) and Cefoperazone Sodium & Sulbactain Sodium for injection(CFZ-SBT) on the metabolism of Escherichia coli(E. coli) DH5 alpha were studied by microcalorimetry. The microbial activity was recorded as power-time curves through an ampoule method with a TAM air isothermal microcalorimeter at 37 degrees C. The parameters such as the growth rate constant(k), inhibitory ratio(I), the maximum power output(P-m) and the time(t(m)) corresponding to the maximum power output were obtained. The lethal doses of CFZ and CFZ-SBT were calculated as 0.1 and 0.25 mu g/mL, respectively. Moreover, according to the relationship between k, P-m, t(m) and c, the conclusion could be made that the CFZ-SBT cannot improve the inhibitory effect on E. coli DH5 alpha in comparison with the CFZ.