Fecal matter is recognized as both a reservoir and a transmission source for various antimicrobial resistance genes (AMRGs). However, the transcriptional activity of AMRGs in swine feces is not well understood. In addition, the effect of fecal microbiota transplantation (FMT) on the excretion of AMRGs has rarely been reported. Our study explored the diversity, abundance, transcriptional activity, and bacterial hosts of AMRGs in Tibetan and Duroc pig feces using metagenomic and metatranscriptomic sequencing technologies. We discovered a significantly higher genomic abundance of AMRGs in the feces of Duroc pigs compared to Tibetan pigs (P < 0.001), although the transcript levels did not show a significant difference. The results showed that the core composition of AMRGs in pig feces varied considerably, with the most transcriptionally active AMRGs being oqxB, tetQ, Bla1, dfrA1, and amrB. Furthermore, the Firmicutes phylum is the main host of AMRGs. By transplanting fecal flora from Tibetan and Duroc pigs into the intestines of Duroc Landrace Yorkshire (DLY) piglets after acute antibiotic exposure, we found that only Tibetan pig fecal flora significantly reduced AMRGs in the feces of DLY piglets (P < 0.05). The effectiveness of Tibetan pig fecal microorganisms in removing AMRGs from DLY pig feces was mainly influenced by microbial communities, especially the Bacteroidota phylum. These findings offer valuable insights for the prevention and control of AMRG pollution.
Importance: To the best of our knowledge, this study represents the first comprehensive analysis of antimicrobial resistance gene (AMRGs) expression in the fecal microbiota of Tibetan and Duroc pigs, employing an integrated metagenomic and metatranscriptomic approach. Our findings indicate a higher risk of AMRGs transmission in the feces of Duroc pigs compared to Tibetan pigs. Given the escalating antimicrobial resistance crisis, novel therapeutic interventions are imperative to mitigate gut colonization by pathogens and AMRGs. In this regard, we investigated the impact of fecal microbiota from Tibetan and Duroc pig sources on AMRGs excretion in Duroc Landrace Yorkshire (DLY) piglets' feces following acute antibiotic exposure. Remarkably, only fecal microbiota sourced from Tibetan pigs exhibited a reduction in AMRGs excretion in DLY piglets' feces. This underscores the significance of evaluating the presence of AMRGs within donor fecal microbiota for effective AMRGs decolonization strategies.
Keywords: antimicrobial resistance genes (AMRGs); fecal microbiota transplantation (FMT); feces; metagenomic; metatranscriptome; pig.