Emergence of a Salmonella Rissen ST469 clinical isolate carrying blaNDM-13 in China

摘要

New Delhi metallo-beta-lactamase-13 (NDM-13) is an NDM variant that was first identified in 2015 and has not been detected in Salmonella species prior to this study. Here we describe the first identification of a Salmonella Rissen strain SR33 carrying bla(NDM-13). The aim of this study was to molecularly characterize SR33's antimicrobial resistance and virulence features as well as investigate the genetic environment of bla(NDM-13). The Salmonella Rissen SR33 strain was isolated from a patient with fever and diarrhea. SR33 belonged to ST469, and it was found to be multidrug-resistant (MDR) and to carry many virulence genes. Phylogenetic analysis showed that SR33 shared a close relationship with most of the Chinese S. Rissen ST469 strains. bla(NDM-13) was located in a transmissible IncI1 plasmid pNDM13-SR33. Sequence analysis of bla(NDM-13)-positive genomes downloaded from GenBank revealed that a genetic context (Delta ISAba125-bla(NDM-13)-ble(MBL)-trpF) and a hybrid promoter (consisting of -35 sequences provided by ISAba125 and -10 sequences) were conserved. ISAba125 was truncated by IS1294 in three plasmids carrying bla(NDM-13), including pNDM13-SR33. To our knowledge, this is the first report of bla(NDM-13) carried by Salmonella. The emergence of bla(NDM-13) in a clinical MDR S. Rissen ST469 strain highlights the critical need for monitoring and controlling the dissemination of bla(NDM-13). bla(NDM-13) carried by a transmissible IncI1 plasmid may result in an increased risk of bla(NDM-13) transmission. IS1294 may be involved in the movement of bla(NDM-13).

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