Plasmid-Mediated Novel bla NDM-17 Gene Encoding a Carbapenemase with Enhanced Activity in a Sequence Type 48 Escherichia coli Strain

• DOI: 10.1128/aac.02233-16
• Publication Date: 2017-02-28T01:40:27Z
• Authors: Zhihai Liu; Yang Wang; Timothy R. Walsh; Dejun Liu; Zhangqi Shen; Rongmin Zhang; Wenjuan Yin; Hong Yao; Jiyun Li; Jianzhong Shen
• Keywords: Aztreonam; Transferability

ABSTRACT Carbapenem-resistant Enterobacteriaceae (CRE) have spread worldwide, leaving very few treatment options available. New Delhi metallo-beta-lactamase (NDM) is the main carbapenemase mediating CRE resistance and of increasing concern. NDM-positive human origin are frequently identified; however, emergence NDM, particularly novel variants, in bacteria food animal has never been reported. Here, we characterize a NDM variant (assigned NDM-17) identified β-lactam-resistant sequence type 48 (ST48) Escherichia coli strain that was isolated from chicken China. Compared to NDM-1, NDM-17 had three amino acid substitutions (V88L, M154L, E170K) confer significantly enhanced activity. NDM-5, only one substitution (E170K) slightly increased isolate carbapenem, as indicated by MIC values. The gene encoding ( bla ) located on an IncX3 plasmid, which readily transferrable recipient E. J53 conjugation, suggesting possibility rapid dissemination . Enzyme kinetics showed could hydrolyze all β-lactams tested, except for aztreonam, higher affinity tested than did NDM-5. this pose threat public health because its transferability