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 plasmidmediated 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 β-lactamase were detected,5 of which produced AmpC β-lactamase enzymes and extended-spectrum β-lactamase enzyme,12 only produced extended-spectrum β-lactamase enzymes,and 3 produced lactamase AmpC β alone.5 strains were transferred successfully.PCR amplification test and the Genbank database sequence alignment analysis showed that 6 strains were amplified to produce plasmidmediated ampC gene,4 of which were CIT and 2 of which were type DHA.Conclusions Clinically,strains of Escherichia coli producing plasmid AmpC enzyme widely spread.Control of the regulatory mechanism of high expression is helpful in guiding clinical antibiotic uses. Key words: Escherichia coli;  AmpC enzyme;  Regulation