致病性大肠埃希氏菌ESBLs基因型的检测及其抑制剂的抑酶保护作用

Genotype detection of extend spectrum β-lactamase of pathogenic Escherichia coli and the inhibitive effect of BLI-tazobactam

【目的】检测致病性大肠埃希氏菌中超广谱β-内酰胺酶(ESBLs)的基因型,初步研究β-内酰胺酶抑制剂(BLI)-他唑巴坦的抑酶保护作用。【方法】对产生ESBLs的5株致病性大肠埃希氏菌,设计并合成TEM-1和是SHV-12对引物,用PCR方法进行了ESBLs的DNA扩增、测序和基因型分析;用试管二倍稀释法测定头孢噻呋与BLI-他唑巴坦钠以不同配比对产生ESBLs大肠埃希氏菌的最小抑菌浓度。【结果】从产生ESBLs细菌中均扩增出了TEM型ESBLs产物,但未扩增出SHV型ESBLs产物;头孢噻呋与BLI-他唑巴坦钠(质量比1∶1～8∶1)联合使用,对产生ESBLs的大肠埃希氏菌的最小抑菌浓度较头孢噻呋单独使用基本降低,最高可降低16倍。【结论】国内畜禽产生ESBLs的大肠埃希氏菌未通过质粒进行细菌间耐药基因的交换,ESBLs的产生与生物种属没有关系,BLI-他唑巴坦有较强的抑制ESBLs作用。

[Objective] The study was to detect genotype of extend spectrumβ-1actamase in pathogenic Enterobacteriaceaes,and to study the inhibitive effect of Tazobactam, a β-lactamases inhibitor （BLI）. [Method] For five Enterobacteriaceaes tested for ESBLs by double-disk method, two primers were designed and synthetized：TEM-land SHV-1,ESBLs gene type was amplified,sequenced and analyzed by PCR;the minimal inhibitory concentrations（MICs） of Cetiofur combined BLI-Tazobaetam to the five Enterobacteriaceae according to different proportions were carried out with two fold dilution method. [Result] The producd bacteria ESBLs were amplified TEM type ESBLs fully, but no SHV type ESBLs;the minimal inhibitory concentrations（MICs） of BLI-Tazobactam combined Cetiofur according to different mass ratios （1 ： 1- 8 ： 1）to the ESBLs bacteria reduced sixteen times compared with Cetiofur. [Conclusion] （1）ESBLs bacteria have not transmited resistant gene through plasmids;（2）The production of ESBLs has no relation with animal genus;（3）The BLI-Tazobactam has better activity to inhibit ESBLs.