Abstract: Objectives To analyze the distribution of Enterobacteriaceae isolated from West China Hospital, investigate the
antibiotic resistance profile of Enterobacteriaceae with decreased susceptibility to carbapenems and explore the molecular
mechanism. Methods Forty-five Enterobacteriaceae strains resistant or with reduced susceptibility to carbapenems were
isolated from patients in West China Hospital. The antimicrobial susceptibility and carbapenemase-producing phenotypes of
the bacteria were examined and specific PCR were performed to determine the molecular mechanism. Results Of the 45
isolates, 17, 21 and 36 were resistant or intermediate strains to imipenem, meropenem and ertapenem, respectively. The
majority of these isolates showed resistance to cephalosporins. The modified Hodge test resulted in the highest positivity rate
(77.8%), followed by EDTA disc test (57.8%) and PBA disc test (22.2%). BlaTEM, blaSHV and blaCTX-M were detected in
60.0%, 53.3% and 15.6% of these strains with reduced susceptibility. The rate of strains carrying 2 or more genes was 44.4%,
and the detection rate of blaIMP was 48.9%. BlaKPC was identified in 4 (8.9%) high-level resistant strains and confirmed to
locate on the plasmid. Conclusion Production of carbapenemase contributes to reduced susceptibility of carbapenems in
Enterobacteriaceae. The presence of blaKPC, MBL and ESBL, and their possible combinations can be the main factor contributing
to carbapenem resistance or reduced susceptibility in Enterobacteriaceae. The KPC-2 carbapenemase gene located on the
plasmids we found in this study can cause potential horizontal transmission across strains.