Two novel blaNDM-1-harbouring transposons on pPrY2001-like plasmids coexisting with a novel cfr-encoding plasmid in food animal source Enterobacteriaceae

• Published in: Journal of global antimicrobial resistance. 2021-09, Vol.26, p.222-226
• Main Authors: Zheng, Xing-Run, Sun, Yin-Huan, Zhu, Jia-Hang, Wu, Si-Li, Ping, Cai, Fang, Liang-Xing, Jiang, Hong-Xia
• Format: Article
• Language: English
• Subjects: Carbapenem; Plasmid; Transposon
• ISSN: 2213-7165; 2213-7173
• DOI: 10.1016/j.jgar.2021.06.006

•Two novel blaNDM-1-harbouring transposons on pPrY2001-like plasmids in Enterobacterales from food animals in China.•pPrY2001-like blaNDM-1 plasmids coexisted with a novel cfr plasmid in P. mirabilis and P. rettgeri isolates.•Both plasmids could transfer at high frequency.•Importance of continuous surveillance of animal-origin Enterobacterales that can serve as a reservoir for ARGs. This study reports identification of the carbapenemase-encoding gene from carbapenem-resistant Enterobacterales from food animals. A total of 40 bacterial isolates recovered from 475 faecal swabs obtained on one farm were tested for the presence of the blaNDM-1 gene by PCR. Species identification of three blaNDM-1-positive strains was conducted by MALDI-TOF/MS. Antimicrobial susceptibility testing was performed by broth microdilution. Transferability of the blaNDM-1 and cfr genes was determined by filter mating. The genetic environment of blaNDM-1 and cfr was analysed by whole-genome sequencing. Two Proteus mirabilis (JPM24 and YPM35) and one Providencia rettgeri (YPR25) carried blaNDM-1. The blaNDM-1 genes were located on conjugable pPrY2001-like plasmids often reported to carry important antimicrobial resistance genes (ARGs). YPR25 and YPM35 shared two almost identical conjugable plasmids, one carrying blaNDM-1 and the other cfr. The blaNDM-1 gene in YPR25 (same as YPM35) and JPM24 was located in two novel transposons, designated Tn6922 and Tn6923, respectively. Tn6922 and Tn6923 carried 14 and 7 ARGs, respectively, and both contained multiple copies of IS26 in the same direction, with a high degree of similarity. Additionally, cfr was located on a plasmid with an unreported high frequency of conjugative transfer in YPR25 (same as YPM35). We identified two novel blaNDM-1-containing transposons (Tn6922 and Tn6923) present on pPrY2001-like plasmids. The pPrY2001-like blaNDM-1 plasmids coexisted with a novel cfr plasmid, and both could transfer at high frequency, highlighting the importance of continuous surveillance of multiresistant Enterobacterales of animal origin that can serve as a reservoir for ARGs.