Summary: Resistance genes move from one microbe to another by several mechanisms. These processes, which are best understood with bacteria, operate through plasmids (conjugation), viruses (transduction), and in some cases direct uptake of DNA from the environment (transformation). Bacteria contain genetic elements called transposons that move genes from one DNA molecule to another. Consequently, chromosomal genes that acquire resistance mutations through spontaneous events can be mobilized by being moved to plasmids that then transfer to other bacteria. Bacterial cells also contain DNA elements called integrons that can assemble resistance genes into short regions of a chromosome. Those regions can move to plasmids and then to other bacteria. Movement of resistance genes involves specific nucleotide sequences at which specific proteins act. Those proteins are potentially subject to man-made inhibitors.