屎肠球菌对氨苄西林耐药pbp5基因突变的研究

Study on mutation of pbp5 of ampidllin resistance in enterococcus faedum

目的研究屎肠球菌对氨苄西林耐药与β内酰胺酶、pbp5基因突变的关系。方法用硝基噻吩(nitrocefin)法检测β内酰胺酶的产生,聚合酶链反应扩增pbp5基因片段,单链构像多态性分析检测pbp5扩增片段的基因突变,测序确定突变的具体位点。结果57株对氨苄西林耐药的屎肠球菌β内酰胺酶阴性;pbp5基因片段均有3至6个位点发生突变,485和499位点突变、466′位插入突变最为常见。结论pbp5基因突变在屎肠球菌对氨苄西林耐药中起着重要作用。

Objective To study the relationship of ampieillin resistance and β laetamase production, and gene mutation on pbp5 gene fragment in Enterococcus faecium. Methods β lactamase production was tested with nitrocefin, the pbp5 gene fragment of 57 isolates of ampicillin-resistant Enterococcus faecium（ ARE. faecium） was amplified by PCR, the mutation of amplified pbp5 gene was detected by single-strand conformation polymorphism（SSCP） , the specific mutation types were confirmed by sequencing. Results β lactamase was negative in 57 isolates of ARE. faeciums; there were 3-6 gene mutation sites on pbp5 gene fragment, and the frequent mutation sites were the position 485 ,499 and 466＇. Conclusion The gene mutation of pbp5 gene fragment may play an important role in the ARE. faecium.