Molecular Epidemiology of New Delhi Metallo--Lactamase-Producing in Food-Producing Animals in China

We conducted a molecular surveillance study for carbapenem-resistant (CRE) colonization in food-producing animals in China that included primarily swine and poultry for three consecutive years. A total of 2,771 samples from food-producing animals and their surrounding environments were collected from different regions in China from 2015 to 2017. Enrichment cultures supplemented with meropenem were used to isolate carbapenem non-susceptible isolates and these were subsequently identified by MALDI-TOF MS. Resistance phenotypes and genotypes were confirmed using antimicrobial susceptibility testing and molecular biological techniques. Genomic characteristics of the carbapenemase-producing isolates were investigated using whole genome sequencing (WGS) and bioinformatic analysis. In total, 88 NDM-positive were identified from 2,771 samples and 96.6% were . The New Delhi metallo--lactamase (NDM)-positive displayed a diversity of sequence types (ST), and ST48 and ST165 were the most prevalent. Three variants of ( , , and ) were detected and WGS indicated that predominated and was carried primarily on IncX3 plasmids. All these isolates were also multiply-drug resistant. These results revealed that food-producing animals in China are an important reservoir for NDM-positive and pose a potential threat to public health.