阴沟肠杆菌Amp C酶的诱导性及对酶抑制剂的敏感性研究

目的 探讨阴沟肠杆菌Amp C酶的特性及对酶抑制剂的敏感性，方法 用琼脂稀释法研究第四代头孢菌素头孢吡肟，第三代头孢菌素头孢他啶，头孢噻肟与β-内酰胺酶抑制剂舒巴坦联合对10株头孢他啶耐药菌的体外抗菌活性。应用紫外法和反转录多聚酶链反应（RT－PCR）研究临床常用β-内酰胺类抗生素对AmpC酶的诱导作用以及3种抑制剂对Amp C酶的抑制作用。结果 舒巴坦不能增强头孢他啶的抗菌作用，第四代头也菌素头孢吡肟对头孢他啶耐药菌有较好的抗菌活性。亚胺培南对Amp C酶的诱导作用较强，酶抑制剂R0481220具有较好的抑制作用，结论 产Amp C酶的阴沟肠杆菌引起的感染可考虑选用第四代头孢菌素头孢吡肟进行治疗。

The inducibility of Amp C enzyme of Enterobacrter cloacae and its susceptibility to enzyme inhibitor

OBJECTIVE: To study the inducibility of Amp C enzyme of Enterobacrter cloacae and its susceptibility to enzyme inhibitor. METHODS: The in vitro activities of the fourth generation cephalosporins-cefepime, the third generation cephalosporins-cefuroxime, cefotaxime, ceftazidime combined with beta-lactamase inhibitor sulbactam against 10 strains of ceftazidime resistant Enterobacter cloacae selected from the hospitals was studied with agar two fold dilution method. The inducibility of beta-lactam antibiotics in common use clinically to Amp C enzyme and the inhibitory action of 3 inhibitors to Amp C enzyme were studied with ultraviolet spectrophotometry and RTPCR. RESULTS: Sulbactam can not enhance the activity of ceftazidime against Enterobacter cloacae. Cefepime has a strong activity against ceftazidime resistant Enterobacter cloacae. Imipenem has a strong inductive action to Amp C enzyme. Ro481220 has a strong inhibitory action to Amp C enzyme. CONCLUSION: Infections caused by Enterobacter cloacae producing Amp C enzyme can be treated by cefepime.