Antioxidant-producing extremophile regulates gut microbiota of black soldier fly larvae to inhibit conjugative transfer mediated by plasmids in municipal sludge.

Summary

This study demonstrates that bioaugmentation of black soldier fly larvae (BSFL) gut with the extremophile bacterium Deinococcus radiodurans reduces oxidative stress and substantially inhibits horizontal transfer of antibiotic resistance genes in municipal sludge. Through molecular mechanisms including heavy metal immobilization and antibiotic degradation, and ecological mechanisms including microbial community restructuring, the bioaugmentation approach reduced key resistance determinants by over 90% and decreased plasmid conjugative transfer frequency by 91%. The findings suggest that antioxidant-producing extremophiles can enhance BSFL-mediated waste processing whilst mitigating antimicrobial resistance dissemination.

Regional applicability

This research addresses antimicrobial resistance mitigation in waste sludge processing, a concern relevant to United Kingdom environmental and public health policy. However, the study was conducted in China and uses black soldier fly larvae as a bioprocessing system; transferability to UK municipal waste management would require assessment of local sludge composition, regulatory framework for BSFL use in waste processing, and climate suitability.

Key measures

Abundance of antibiotic resistance genes (aphA, tetA), class 1 integron integrase gene (intI1), conjugative transfer gene (traG), reactive oxygen species levels, expression of G-protein and s14e genes in BSFL gut, microbial community composition, conjugative transfer frequency of RP4 plasmid, abundance of Pseudomonadota carrying mobile genetic elements

Outcomes reported

The study measured reduction in antibiotic resistance genes (ARGs), conjugative transfer frequency, and changes in microbial community structure in municipal sludge processed by black soldier fly larvae bioaugmented with Deinococcus radiodurans. Key outcomes included >1 order of magnitude reduction in specific ARGs and integrase genes, and a 91% reduction in RP4 plasmid conjugative transfer frequency.

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