Clinical Isolate of Escherichia coli Producing Extended-spectrum AmpC β-Lactamases(ESACs) with ClassI Integron

OBJECTIVE To detect the genes of plasmid-mediated AmpC and ESBL β-lactamases and classⅠ integron in clinical isolate of Escherichia coli.METHODS The bacterial susceptibility to antimicrobial agents for strain E50 was determined by agar dilution method.The genes of AmpC,ESBLs,and intⅠ1 were analyzed using PCR and verified DNA sequencing.Conjugation experiment was used to study the transfer of drug resistance.RESULTS The strain was only susceptible to imipenem.CTX-M-15,SHV-1,TEM-1,DHA-1 and intⅠ 1 genes were positive.CONCLUSIONS It has complicated mechanism of drug resistance.Some of clinical strains producing plasmid-mediated AmpC β-lactamase are accompanied by extensively producing ESBLs.Carbapenems are the best choice for treatment infection caused by strains producing ESACs.More attention should be paid to integron which plays an important role in multi-resistance.