产质粒介导AmpC酶大肠埃希菌的流行病学调查及其酶的表达调控

目的研究产质粒介导AmpC酶大肠埃希菌的流行病学状况及其酶的表达调控。方法选择临床中分离到的疑似产质粒介导AmpC酶的大肠埃希菌30株，对产质粒介导AmpC酶大肠埃希菌的流行病学特征进行调查分析，并行转移接合试验。用6组引物对提取的细菌质粒DNA进行多重PCR扩增，从而对质粒介导的AmpC酶的表达调控进行分析。结果流行病学调查，共检出20株产p-内酰胺酶菌株，其中有5株菌株同时产AmpCp-内酰胺酶和超广谱p-内酰胺酶，12株只产超广谱p-内酰胺酶，3株只产AmpCp-内酰胺酶，5株转移接合成功。PCR扩增试验后，与Genbank数据库进行序列比对分析，发现有6株扩增产生质粒介导的AmpC基因，其中CIT型4株，DHA型2株。结论产质粒AmpC酶大肠埃希菌在临床上广泛传播，把握其持续高表达的调控机制，有助于指导临床合理使用抗牛素。

An epidemiological survey on Escherichia coli producing plasmid-mediated AmpC enzyme and regulation of expression of AmpC enzyme

Objective To explore the expression and regulation of Escherichia coli producing plasmid-mediated AmpC enzymes. Methods 30 strains of E. Coli producing plasmid-mediated AmpC enzyme were isolated. An epidemiological survey were conducted on Escherichia coli producing plasmid- mediated AmpC enzyme, and transfer bonding test was carried out. 6 primer bacterial plasmid DNA extracted for the multiplex PCR amplification were set. Results According to the epidemiological survey, a total of 20 strains producing 13 -lactamase were detected, 5 of which produced AmpC 13 -lactamase enzymes and extended-spectrum 13 -lactamase enzyme, 12 only produced extended-spectrum 13 -lactamase enzymes, and 3 produced lactamase AmpC 13 alone. 5 strains were transferred successfully. PCR amplification test and the Genbank database sequence alignment analysis showed that 6 strains were amplified to produce plasmid- mediated ampC gene, 4 of which were CIT and 2 of which were type DHA. Conaclusions Clinically, strains of Escherichia coli producing plasmid AmpC enzyme widely spread. Control of the regulatory mechanism of high expression is helpful in zuidinz clinical antibiotic uses.