Emergence of blaNDM-9-bearing tigecycline-resistant Klebsiella aerogenes of chicken origin
Yan Li, Qian Wang, Xia Xiao, Ruichao Li, Zhiqiang Wang
Abstract
ABSTRACT Objectives The aim of this study was to characterise a tigecycline-resistant bla NDM-9 -bearing Klebsiella aerogenes strain (HNHF1) of chicken origin. Methods Strain HNHF1 was characterised by phenotypic antimicrobial susceptibility testing, PCR, conjugation assays, S1 nuclease pulsed-field gel electrophoresis (S1-PFGE), whole-genome sequencing and bioinformatics analysis. Results The bla NDM-9 gene was located on an IncHI2 plasmid (pHNHF1_NDM-9) carrying various antimicrobial resistance genes. Moreover, the genetic context ΔIS Aba125 – bla NDM-9 – ble MBL – trpF is similar to other bla NDM -bearing genetic contexts. TA cloning experiments showed that tet (A) variants may play a partial role in high-level tigecycline resistance in HNHF1. Conclusion This is the first report of a tigecycline-resistant bla NDM-9 -bearing IncHI2 plasmid in a K. aerogenes ST4 isolate of animal origin, which poses a great threat to public health. Further comprehensive surveillance is needed.