FIGURE 2.

Natural and artificial mechanisms that control the transmission of conjugative plasmids. Natural mechanisms include RM and CRISPR-Cas systems (encoded by the recipient chromosome), exclusion systems (used to prevent the entrance of related plasmids in the same recipient), and fertility inhibition systems (encoded by plasmids in donor bacteria). Artificial mechanisms interfere with key components of the conjugative process, such as the relaxase, the pilus, or conjugation-related ATPases.