β-内酰胺酶研究进展

The Research Develepment of β-Lactamases

细菌主要是通过产生质粒介导的超广谱β－内酰胺酶，染色体介导的ＣｌａｓｓＣ酶、增加广谱酶的产量及降低外膜的通透性等而对头孢他定、头孢噻肟等第三代头孢菌素耐药。其酶的种类繁多，特性各异。目前从临床产酶耐药菌中得到的ＴＥＭ型酶已报道到ＴＥＭ－６８，ＳＨＶ型酶到ＳＨＶ－２４，ＣｌａｓｓＣ酶有 ＡｍｐＣ酶和 ＯＸＡ酶等。随着β－内酰胺酶抑制剂与β－内酰胺类抗生素的联合应用，近年来又发现了耐抑制剂的β－内酰胺酶（ｉｎｈｉｂｉｔｏｒ－ｒｅｓｉｓｔａｎｔ ＴＥＭβ－ｌａｃｔａｍａｓｅ），简称ＩＲＴ－β－内酰胺酶。它们是通过ＴＥＭ型酶变异而使抑制剂的抑酶作用减弱。大多数耐抑制剂的β－内酰胺酶都是 ＴＥＭ－１和 ＴＥＭ－２的衍生酶。另外，有报道说，近年来抑制剂耐药的β－内酰胺酶在ＳＨＶ型酶的家族也出现了。

Bacteria resistance to third generational cephalosporin such as cefotazidime and cefotaxime is mainly due to producing of plasmid mediated ESBLs and chromosome mediated Classβ-lactamases, increasing of the production of broad spectrumβ-lactamase and decreaing the permeability of out-membrane. There are various β-lactamases with different characteristics. TEM typeβ-lactamases reported have been now from TEM- I to TFM-68, and SHV typeβ-LActamases from SHy-1 TO SHV-24. Class Cβ-lactamases include Amp C, OXAβ-lactamase and so on. Following the use of the combination of β-lactamase inhibitors andβ- lactame antibiotics, Inhibitor-resistant TEM β-lactamases (IRT-13-lactamase) have appeared. Most of them are derived from TEM- 1 and TEM-2. IRT-13-lactamase are also discovered in SHV typeβ-tactamase family recently.