Antimicrobial activity of ceftriaxone plus sulbactam on extended-spectrum β-lactamase-producing E.coli in vitro

Objective To study of antimicrobial activity of ceftriaxone plus sulbactam(CRO/SCB ,2∶1) on extended-spectrum β-lactamase (ESBL)-producing E.coli in vitro. Methods The MICs were determined by broth macrodilution method. The bacteria were resuspended in MH broth with drugs for drawing the time-kill curve and pharmacokinetic time-kill curve. Results The MIC50 and MIC90 of ceftriaxone and ceftriaxone/sulbactam against ESBL-producing Escherichia coli and Klebsiella pneumonia were 128 and 32 mg L-1 ,128 and 64 mg·L-1. According to the time-kill studies,ceftriaxone/sulbactam groups displayed obvious antibacterial activities. For the pharmacokinetic time-kill curve,the group of ceftriaxone/pharmacokinetic procedure and the group in which ceftriaxone/sulbactam is keeping in the proportion 2∶1 displayed similar and excellent antibacterial activity on ESBL-producing E.coli. Conclusion The fast decline of sulbactam concentration in ceftriaxone/sulbactam whose concentration is pharmacokinetic procedure does not obviously decrease antibacterial activity to ESBL-producing E.coli.