Study on resistance mechanisms and epidemiology of Enterobacteriaceae with decreased carbapenem susceptibility / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the resistance mechanisms and epidemiology of Enterobacteriaceae isolated from clinical with reduced susceptibility to imipenem or meropenem.Methods 18 strains of Enterobacteriaceae with reduced carbapenem susceptibility were collected during January to August in 2010.The MICs of these strains were determined using automated microbial identification system.ESBLs,AmpC and KPC were tested using the agar dilution method.PCR amplification and DNA sequence were performed to analyze the KPC genes,PFGE was used to examine the molecular epidemiology.Results All 18 strains were detected ESBLs and AmpC,14 strains were detected KPC-2.3 strains with EDTA paper method positive may produce other metal carbapenem,in which 2 strains harbor KPC-2.PFGE types indicate that there were six genotypes among 15 strains of Klebsiella pneumoniae.Conclusion Plasmid-mediated KPC-2 was the main reason which makes Enterobacteriaceae reducing carbapenem susceptibility and causes short-term epidemic in hospital.Clinical strains harboring KPC-2 gene may carry multiple resistance genes meanwhile.