Identification of blaIMI-mediated carbapenem-resistant Enterobacter from a duck farm in China

Carbapenem- and colistin-resistant Enterobacter has been a clinical and therapy problem in recent years. Here, we report the carbapenem- and colistin-resistant Enterobacter harboring blaIMI isolated from intestinal samples and the environment of a duck farm in China. Four blaIMI-positive Enterobacter isolates were resistant to carbapenem and colistin. Three blaIMI subtypes were detected in different molecular categories of Enterobacter. The detection of the various IMI producers highlights the diversity of carbapenemases in a duck farm. Whole-genome sequencing demonstrated the bla(IMI) genes were present in chromosomes or plasmids in these strains. The conjugation experiment demonstrated the ability of bla(IMI)-carrying plasmid to transmit horizontally. The molecular evolution characteristics were examined through comparative genetic analysis. The study demonstrated the presence of chromosomal and plasmid bla(IMI) and the bla(IMI)-carrying plasmid exhibits a horizontal transmission between Enterobacter and Escherichia coli C600. The similar genetic content was discovered between two blaIMI-16-positive Enterobacter asburiae. In addition, a bla(IMI-16)-carrying plasmid is an IncFII(Yp) plasmid, and a substantial amount of mobile genetic elements were identified around bla(IMI)-16. The ISlike elements and IncFII(Yp) plasmid are significant in the propagation of bla(IMI). Our study provides evidence for the transmission of diverse bla(IMI) genes in China and supplies additional reference data for bla(IMI)-positive antimicrobialresistant Enterobacter. Routine surveys of bla(IMI)-positive Enterobacter from animal-raising environments must be given more focus.

Automated summary

Carbapenem- and colistin-resistant Enterobacter strains harboring blaIMI were isolated from intestinal samples and the environment of a duck farm in China. The study demonstrated the diversity of carbapenemases in a duck farm and provided evidence for the transmission of bla(IMI) genes. Whole-genome sequencing and comparative genetic analysis revealed the presence of chromosomal and plasmid bla(IMI) and identified the horizontal transmission of bla(IMI)-carrying plasmids.