EMERGENCE OF NDM-1-PRODUCING ESCHERICHIA COLI IN THE SHANDONG PROVINCE OF CHINA

MAO-LI YI¹, JIANG-DONG DU¹, LI-HUA JIANG¹, QIAN LI¹, JING-YING WU¹, CHENG-MING SUN¹

¹Department of laboratory, Yantai Yuhuangding Hospital, Yantai, China 264000

Objective: The goal of this study was to investigate the drug resistance mechanism and molecular epidemiology of five strains of PAN-drug resistant Escherichia coli isolated from June 2013 to December 2013 in Yantai Yuhuangding Hospital of Shandong regional medical center.

Method A modified Hodge test and an imipenem-EDTA phenotypic confirmatory test were performed to detect production of metallo-β-lactamases. PCR-based surveillance was used to detect the blaNDM-1 gene. For blaNDM-1-positive isolates, antibiotic susceptibility was assessed and molecular typing was performed using PFGE. The genetic location of bla NDM-1 was determined through the analysis of PFGE profiles of S1 nuclease-digested genomic DNA and Southern blot hybridization. Plasmid transfer to E. coli recipients was investigated using filter mating and electroporation.

Results: Five isolates harboring blaNDM-1 were identified; the strains were clonally diverse and carried blaNDM-1 on diffe- rent plasmids. Plasmids carrying blaNDM-1 were successfully transferred from four of the five isolates to E. coli recipients.

Conclusion: We describe the emergence of E. coli producing NDM-1 isolated from the Yantai Yuhuangding hospital of Shandong Province Regional Medical Center production of China. A systemic surveillance network should be established for monito- ring these resistant bacteria.