bla NDM-1 -producing multidrug-resistant Escherichia coli isolated from a companion dog in China.

OBJECTIVES: This study characterised a blaNDM-1 -producing Escherichia coli isolate from a companion dog.

METHODS: The E. coli strain was isolated from a surveillance study of carbapenem-resistant Gram-negative bacteria from companion animals in the Animal Teaching Hospital of China Agricultural University (Beijing, China) in 2013. Species identification was performed using an API 20E system and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Minimum inhibitory concentrations (MICs) of various antimicrobial agents were determined by agar dilution. Multilocus sequence typing (MLST) was performed and various carbapenemase genes, including blaNDM , blaIMP , blaVIM , blaSME , blaIMI , blaKPC , blaGES , blaSPM , blaGIM , blaNMC , blaDIM , blaSIM , blaOXA-23 , blaOXA-24 , blaOXA-48 , blaOXA-51 and blaOXA-58 were screened by PCR. S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) and Southern blotting as well as a modified random primer walking strategy were performed to analyse the location and genetic environment of blaNDM-1 .

RESULTS: An E. coli isolate belonging to ST167 was found to be positive for the blaNDM-1 gene and exhibited resistance to β-lactams, tetracycline, gentamicin, fosfomycin and ciprofloxacin. The blaNDM-1 gene in this strain was located on an ca. 150-kb plasmid and the flanking sequences of the blaNDM-1 -carrying region (a common gene cluster, ΔISAba125-blaNDM-1 -ble-trpF-ΔdsbC) exhibited >99% identity to the corresponding regions of blaCTX-M-15 -harboring plasmids in nosocomial E. coli ST131 isolates.

CONCLUSIONS: This is the first report of blaNDM-1 -producing ST167 E. coli in a companion dog. Companion animals harbouring carbapenemase-producing isolates are an upcoming public health threat and it is worthy paying attention to the emergence of carbapenem resistance in companion animals.