Study on interaction between antibiotics and Escherichia coli DH5α by microcalorimetric method.

A microcalorimetric technique based on the bacterial heat output was applied to evaluate the influence of antibiotics PIP ( Piperacillin Sodium) and composite preparation of PIP and SBT ( Sulbactam Sodium) on the growth of E. coli DH5α. The power–time curves of the growth metabolism of E. coli DH5α were studied using a TAM Air Isothermal Microcalorimeter at 37°C. By analyzing the power–time curves, the parameters such as growth rate constants ( k), inhibitory ratio ( I), the maximum heat power ( P m) and the time of the maximum heat power ( t m) were obtained. The results show that different concentrations of antibiotics affect the growth metabolism of E. coli DH5α. The PIP in the concentration range of 0–0.05 µg mL–1 has a stimulatory effect on the E. coli DH5α growth, while the PIP of higher concentrations (0.05 –0.25 µg mL–1) can inhibit its growth. It seems that the composite preparation composed of PIP and SBT cannot improve the inhibitory effect on E. coli DH5α as compared with the PIP. [ABSTRACT FROM AUTHOR]