Recovery and microbial host assignment of mobile genetic elements in complex microbiomes: insights from a spiked gut sample.

Mobile genetic elements (MGEs) are major drivers of horizontal gene transfer, including the spread of antimicrobial resistance (AMR) genes. However, determining the microbial host of an MGE in complex microbiomes remains challenging. Here, we spike a niche-aspecific Mobile genetic elements are important contributors to horizontal gene transfer, including of antimicrobial resistance genes. Understanding which microbes carry these mobile elements is vital to assess the spread of resistance. Here, we use a nanopore adaptive sampling approach to increase detection of low-abundance bacteria and mobile elements and use DNA methylation detection and Hi-C sequencing to determine mobile element hosts. By introducing a known bacterium and isolating a native strain, we could evaluate the performance of these methods, indicating that although powerful, they require careful experimental design, interpretation, and validation. However, when combined, these approaches enable a comprehensive investigation of mobile elements and gene transfer dynamics in complex environments.