Detection of Extended-spectrum β-Lactamases and AmpC β-Lactamases and Analysis of Drug Resistance in Enterobacter cloacae

OBJECTIVE To investigate the genotypes of extended-spectrum β-lactamases(ESBLs)and drug resistance in Enterobacter cloacae for clinical treatment.METHODS E.cloacae was identified by VITEK-AMS;ESBLs and AmpC β-lactamases phenotypes were detected by three-dimensional tests.Detection of β-lactamases resistant genes were performed by PCR.Plasmid conjugation test was used to determine the location and the transmission of encoding genes of β-lactamases.The antibotic susceptibility of E.cloacae was detected according to the CLSI guideline.RESULTS The incident rate of ESBLs producing E.cloacae was 48.8% in 86 strains.CTX-M was the main type of ESBLs.The detection rate of CTX-M-3,CTX-M-9,CTX-M-14 and SHV-12 genotypes in isolates were 27.9%,16.3%,3.4% and 18.6%,respectively.Strains producing both ESBLs and AmpC β-lactamases were 11(12.8%).The strains only producing ESBLs or AmpC β-lactamases were 31(36.0%) and 8(9.3%),respectively.The sensitive rate of ESBLs isolates to imipenem was 100.0%.Eight ESBLs strains were conjugated successfully.CONCLUSIONS CTX-M and SHV-12 are the main genotypes of ESBLs strains.ESBLs genes can be horizontally transferred to recipient by plasmid conjugated test.