A case of blaNDM-1-positive Salmonella Kottbus,Denmark, November 2020

We present a case of carbapenemase-producing blaNDM-1-positive Salmonella Kottbus in an 82-year-old Danish man. The blaNDM-1 was also identified in Escherichia coli and Citrobacter freundii in the same patient on the same 43 kb IncN2 plasmid, suggesting in vivo inter-species plasmid transfer. A NCBI BLAST analysis of the plasmid (pAMA003584_NDM-1) identified 12 highly similar plasmids, all originating from east and south-east Asia. This case could be the first confirmed case of blaNDM-1-positive Salmonella not related to travel outside Europe.

In Denmark, non-typhoidal Salmonella (NTS) is notifiable by the diagnosing laboratory and S. enterica subsp. enterica serovar Kottbus is a rare serovar, accounting for ca 1% of all NTS-cases registered over the past 20 years (https://statistik.ssi.dk). S. Kottbus has been isolated from poultry, cattle, pigs and reptiles 1] and has been identified in several outbreaks 2-5].Carbapenems are not first-choice drugs for the treatment of Salmonella. However, the emergence of resistance to carbapenems, often last-line antimicrobial agents, is a major concern. In human Salmonella infections, five carbapenemases are of major clinical importance, namely Klebsiella pneumoniae carbapenemases (KPC; class A), New Delhi metallo-β-lactamase (NDM; class B), Verona integron-encoded metallo-β-lactamase (VIM; class B), and imipenemase (IMP; class B), and oxacillinases (OXA e.g. OXA-48; class D) 6]. We present a case of an NDM-1 carbapenemase-producing S. Kottbus, isolated in a Danish man who did not have travel history outside of Europe.