Transmission and molecular characteristics of bla(NDM)-producing Escherichia coli between companion animals and their healthcare providers in Guangzhou, China

Objectives To determine the transmission and molecular characteristics of bla(NDM)-producing Escherichia coli between companion animals and their healthcare providers at veterinary clinics in Guangzhou, China. Methods A total of 359 samples from companion animals and their healthcare providers were collected at 14 veterinary clinics in Guangzhou, China. Genomic characteristics and clonal relationships for bla(NDM)-positive E. coli and complete plasmid sequences were characterized based on WGS data from combined Illumina and MinION platform reads. Results Forty-five bla(NDM)-positive bacteria were recovered from companion animals (n = 43) and their healthcare providers (n = 2) at 10 veterinary clinics. Overall, E. coli (73.3%, 33/45) and Klebsiella pneumoniae (13.3%, 6/45) were the most prevalent species among the seven species of bla(NDM)-positive bacteria. Four bla(NDM) variants (bla(NDM-1), bla(NDM-4), bla(NDM-5) and bla(NDM-7)) were identified in 45 bla(NDM)-positive bacteria and bla(NDM-5) was the most prevalent (77.8%, 35/45). WGS indicated that the most prevalent STs were ST405 (8/33), ST453 (6/33), ST457 (6/33) and ST410 (5/33) among the 33 bla(NDM)-positive E. coli isolates. Phylogenomics and PFGE analysis revealed that clonal spread of bla(NDM)-positive ST453 E. coli isolates between companion animals and their healthcare providers was evident. In addition, two novel IncFIB plasmids carrying bla(NDM-4) (pF765_FIB and pG908_FIB) were found in this study and indicated that IS26 may promote the horizontal transmission of bla(NDM) between different plasmid types. Conclusions In this study we conducted a large-scale investigation on the prevalence of bla(NDM)-positive E. coli isolates from companion animals and their healthcare providers and revealed the clonal spread of bla(NDM)-positive E. coli isolates between these two groups.