A One Health Approach Reveals Farms as Hotspots for Co-Occurrence of Mcr-1 and blaNDM-1 Resistance Genes in Fuyang City, China

Zhaoqian Meng,1,* Ziyi Bu,2,* Hao Guo,1 Guoxia Guo,1 Xialian Gao,1 Liangzi Guo,1 Li Li,1 Wei Zhang3 1Fuyang Center for Disease Control and Prevention, Fuyang, Anhui, People’s Republic of China; 2Clinical College of Anhui Medical University, Hefei, Anhui, People’s Republic of China; 3The Second People’s Hospital of Fuyang, Fuyang Infectious Disease Clinical College of Anhui Medical University, Fuyang, Anhui, People’s Republic of China*These authors contributed equally to this workCorrespondence: Wei Zhang, The Second People’s Hospital of Fuyang City, No. 1088, West Yinghe Road, Fuyang, Anhui, People’s Republic of China, Email [email protected]: The plasmid-mediated mcr-1 and blaNDM-1 genes threaten the efficacy of last-line antibiotics. This study aimed to elucidate their prevalence and transmission risk within a “One Health” framework in Fuyang City, China, a region with intensive animal farming.Methods: A total of 840 samples were collected and screened for mcr-1 and blaNDM-1 using PCR, with confirmation by sequencing. DNA was extracted from all samples (directly from sample material for rat, pig, and poultry sources; from cultured isolates for clinical and food-derived strains). The samples comprised clinical strains (n=120), strains isolated from food samples (n=38), rat intestines (n=200), pig feces (n=194), and environmental swabs from live poultry markets (n=288).Results: The mcr-1 gene was prevalent (19.88%), particularly in pig feces (34.02%) and poultry environments (33.68%), while blaNDM-1 was less common (2.14%) but also highest in poultry environments (4.17%). Notably, we identified 25 samples (8.68% of poultry environments) that co-harbored both genes, constituting a concentrated hotspot for co-resistance. In stark contrast, clinical and food samples showed minimal to no detection of these genes. Statistical analysis confirmed significant differences in detection rates among sample types (P < 0.05).Conclusion: Poultry farms are identified as crucial epicenters for the co-selection of mcr-1 and blaNDM-1 in Fuyang. The high-density coexistence of these genes in a single environment poses a substantial public health risk, underscoring the urgent need for targeted interventions in the animal agriculture sector to prevent the transmission of pan-drug resistant bacteria from these reservoirs to human populations. This convergence within a farming environment suggests a high-risk interface for the emergence of pan-drug resistant pathogens, with potential for dissemination to humans via the food chain or environment, highlighting a region-specific One Health concern.Keywords: one health, mcr-1, blaNDM-1, co-resistance, poultry farm, antimicrobial resistance