Detection of a NDM-5-producing Klebsiella pneumoniae sequence type 340 (CG258) high-risk clone in swine

The emergence and rapid increase of carbapenem-resistant Entembacteriaceae among food-producing animals poses a serious threat to public health. The aim of this study was to investigate the presence and dissemination of bla(NDM-5) in porcine Klebsiella pneumoniae isolates. Of 19 mempenem-resistant K. pneumoniae isolates, 18 were bla(NDM-5)-positive and one carried bla(NDM-1). Susceptibility testing indicated that all bla(NDM)-carrying K. pneumoniae showed a multiple drug resistance (MDR) profile. The bla(NDM-5) gene was located on a conjugative IncX3 plasmid of similar to 46-kb in all 18 bla(NDM-5)-carrying isolates. MLST analysis revealed that ST340 (n = 8), a member of the worldwide existing high-risk epidemic clonal group 258 (CG258), was predominant. Furthermore, whole genome sequence (WGS) analysis for one representative ST340 K. pneumoniae Kp19110124 showed a MDR profile for a wide range of antimicrobial agents, including meropenem, various cephalosporins, azteonam, gentamicin, ciprofloxacin, and florfenicol. Phylogenetic analysis exhibited that K. pneumoniae ST340 strains were clustered into one branch, which had spread across host species and across continents. Among them, K. pneumoniae Kp19110124 displayed a very close relationship with a clinical isolate collected from a patient in Canada. In conclusion, these results reveal the presence of a bla(NDM-5)-carrying conjugative IncX3 type plasmid into K. pneumoniae ST340 clone, which then may accelerate the dissemination of the bla(NDM-5) gene in porcine K. pneumoniae isolates. The detection of high-risk bla(NDM-5)-carrying K. pneumoniae ST340 in food-producing animal poses a serious threat to public health.