Can Antibiotic Resistance Genes in Household Food Waste be Reduced by Earthworm Vermicomposting? Underpinning Mechanisms and Strategies

Hundreds of million tons of food waste (FW) is annually generated from the household sectors. Also, it is regarded as a main conduit for the spread of antibiotic resistance genes (ARGs) in the ‘human–environment’ loop. This paper mainly reviews recent studies on the occurrence and dynamics of ARGs in FW and discusses the ins, outs, and spreads of ARGs by the vermicomposting. Our analysis shows that the concentration of FW-borne ARGs and their major hosts (human pathogens) can be effectively reduced and eliminated in the earthworm guts, respectively, due to the increased bacterial fitness cost for ARG-spreading and earthworm immune responses. Of particular interest, the removal performance could be improved by the measures including agricultural waste co-composting and enforced aeration, which concurrently lead to an elevated vermicomposting loading rate and enhanced quality of compost end-products. Furthermore, our review argues that functional microbial inoculum-feeding possibly results in microbial colonization and stable reproduction in earthworm guts. This proposed optimization approach may be instrumental to contain the spread of ARGs and increase the vermicomposting treatment efficiency at the same time. Graphical Abstract: [Figure not available: see fulltext.].