Spatial Mapping and Host Linking of Mobile Genetic Elements in Complex Microbiomes - Mapping MGEs in oral plaque biofilms at high specificity

We stained for the GFP gene in samples that contained mixtures of plaque and GFP-transformed E. coli. We mapped mefE, an AMR gene located on a plasmid and encoding an antibiotic efflux pump, in the plaque metagenomic data of volunteer A but not volunteer B. To test the efficacy of gel embedding and clearing, we used orthogonal FISH probes, designed to not target any sequence in the plaque. We identified a T7-like prophage via metagenomic analysis and developed probes targeting its capsB gene, which encodes the minor capsid protein. We identified a highly prevalent prophage of the class Caudoviricetes with a large terminase gene, termL, and were able to design a large set of FISH probes to stain in three different colors simultaneously. We identified three non-plasmid AMR genes within metagenome assembled genomes: patA, patB, and adeF.