Elimination and analysis of mcr-1 and blaNDM-1 in different composting pile layers under semipermeable membrane composting with copper-contaminated poultry manure

The mcr-1 and blaNDM-1 elimination in copper contamination poultry manure was evaluated by semi-permeable membrane composting. The results showed the mcr-1 in control and high copper groups could not be removed, but mcr-1 decreased superlatively 80.1% in low copper treatment group. BlaNDM-1 was increased after composting, especially the copper addition groups, the results indicated that the relative abundance of mcr-1 and blaNDM-1 was obviously different in the different pile layers of copper treatment groups. Three mobile gene elements (MEGs) correlated both mcr-1 and blaNDM-1, copB correlated mcr-1, czcA and copA correlated both mcr-1 and blaNDM-1. The major phyla were Firmicutes, Bacteroidota, Actinobacteriota and Proteobacteria in all layers. The correlation analysis showed that the antibiotic resistance genes (ARGs) potential hosts could be influenced by copper form and physicochemical parameters. Semi-permeable membrane composting could decrease the abundance of major potential pathogens. Furthermore, the composting pile was not homogeneous by semipermeable membrane composting.

Automated summary

The semi-permeable membrane composting was effective in reducing the levels of mcr-1 and blaNDM-1 in copper-contaminated poultry manure. Although mcr-1 levels decreased significantly in the low copper treatment group, blaNDM-1 levels increased after composting, especially in the copper addition groups. The relative abundance of mcr-1 and blaNDM-1 varied significantly in different pile layers of copper treatment groups.