Mitigation of antibiotic resistance genes and pathogens via black soldier fly-mediated bioconversion of chicken...

The widespread use of antibiotics in poultry production has resulted in manure residues that harbor antibiotic resistance genes (ARGs) and multidrug-resistant bacteria, posing serious risks to environmental and public health. The black soldier fly (Hermetia illucens) is an emerging bioconversion agent that efficiently transforms organic wastes into nutrient-rich biomass. However, its impact on the fate of ARGs and pathogenic bacteria during poultry manure recycling remains insufficiently understood. This study investigated the dynamics of microbial communities and ARGs during black soldier fly larvae (BSFL)-mediated bioconversion of chicken manure. Eight representative ARGs (sul1, tetA, tetB, tetG, blaTEM, blaCTX, blaSHV, and qnrB) were quantified by qPCR, while bacterial community composition was analyzed through 16S rRNA sequencing and functional prediction using PICRUSt. BSFL treatment significantly reduced the relative abundance of tetracycline resistance genes (tetA, tetB, tetG) and pathogenic taxa such as Acinetobacter, Clostridium, Enterococcus, and Escherichia-Shigella in manure residues. In contrast, ARGs including sul1, qnrB, and β-lactamase-related genes accumulated in larval guts, likely due to enrichment of ARG-associated genera (Providencia, Enterococcus, Dysgonomonas) carrying mobile genetic elements. Overall, BSFL bioconversion effectively mitigated ARGs and pathogens in manure residues, contributing to safer livestock waste recycling. Nonetheless, ARG retention within larval guts highlights the need for post-harvest safety measures to prevent downstream dissemination. These findings advance the understanding of ARG ecology in biological waste treatment systems and support the development of sustainable manure management strategies aligned with the One Health framework.