Detection and epidemiology of NDM-type carbapenemase in Esherichia coli / 中国感染与化疗杂志

ABSTRACT

Objecive To investigate the prevalence of NDM-type carbapenemases in the carbapenem-resistant Escherichia coli strains collected from Ruijin Hospital, Shanghai Jiaotong University School of Medicine. The epidemiological characteristics of NDM-type carbapenemase-producing isolates were analyzed.Methods Eighteen strains were collected from November 2013 to January 2015 in the clinical microbiology laboratory of Ruijin Hospital. All of them were resistant to imipenem or meropenem (inhibition zone diameter≤19 mm). The blaNDM gene was detected by PCR. The amplified products were subjected to sequencing analysis. Conjugation experiment was carried out to verify the transferability of plasmids. Multilocus sequence typing (MLST) and pulsed field gel electrophoresis (PFGE) were performed to analyze the molecular epidemiology.Results The blaNDM gene was identified in 6 strains, 4 of which had blaNDM-1-type and 2 had blaNDM-5-type carbapenemase gene. Three strains were positive in the conjugation experiment. MLST analysis showed that 6 NDM carbapenemase-producing isolates belonged to ifve sequence types, corresponding to five PFGE-DNA patterns (A-E). Two of these isolates shared the identical sequence type (ST5018) and nearly the same PFGE-DNA patterns (A1, A2).Conclusions NDM-type carbapenemase-producing E. coli is identified in this study. Most blaNDM-positive cases were sporadic. Plasmid might play an important role in the spread of blaNDM inE. coli. The blaNDM-5 type carbapenemase gene was first identified in Shanghai, to which more attention should be paid.