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Identification of New Delhi Metallo-β-lactamase 1 in Acinetobacter lwoffii of Food Animal Origin
  • Yang Wang, China Agricultural University
  • Conming Wu, China Agricultural University
  • Qijing Zhang, Iowa State University
  • Jing Qi, Shandong Academy of Agricultural Sciences
  • Hebing Liu, China Agricultural University
  • Yu Wang, China Agricultural University
  • Tao He, China Agricultural University
  • Licai Ma, China Agricultural University
  • Jing Lai, China Agricultural University
  • Zhangqi Shen, Iowa State University
  • Yuqing Liu, Shandong Academy of Agricultural Sciences
  • Jianzhong Shen, China Agricultural University
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Background To investigate the presence of metallo-β-lactamase (MBL) genes and the genetic environment of the New Delhi metallo-β-lactamase gene blaNDM-1 in bacteria of food animal origin. Methodology/Principal Findings Gram-negative bacteria with low susceptibility to imipenem (MIC>8 µg/mL) were isolated from swab samples collected from 15 animal farms and one slaughterhouse in eastern China. These bacteria were selected for phenotypic and molecular detection of known MBL genes and antimicrobial susceptibility testing. For the blaNDM-1 positive isolate, conjugation and transformation experiments were carried out to assess plasmid transfer. Southern blotting was conducted to localize the blaNDM-1 genes, and DNA sequencing was performed to determine the sequences of blaNDM-1 and the flanking genes. In total, nine Gram-negative bacteria of four different species presented a MBL phenotype. blaNDM-1 was identified on a mobile plasmid named pAL-01 in an Acinetobacter lwoffii isolate of chicken origin. Transfer of pAL-01 from this isolate to E. coli J53 and JM109 resulted in resistance to multiple β-lactams. Sequence analysis revealed that the blaNDM-1 gene is attached to an intact insertion element ISAba125, whose right inverted repeat (IR-R) overlaps with the promoter sequence of blaNDM-1. Thus, insertion of ISAba125 likely enhances the expression of blaNDM-1. Conclusion The identification of a blaNDM-1- carrying strain of A. lwoffii in chickens suggests the potential for zoonotic transmission of blaNDM-1 and has important implications for food safety.

This article is from PLoS ONE 7(5): e37152. doi:10.1371/journal.pone.0037152. Posted with permissino.

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Yang Wang, Conming Wu, Qijing Zhang, Jing Qi, et al.. "Identification of New Delhi Metallo-β-lactamase 1 in Acinetobacter lwoffii of Food Animal Origin" PLoS ONE Vol. 7 Iss. 5 (2012) p. e37152
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