Ecological factors influencing the transfer of plasmids in vitro and in vivo.

Plasmid transfer in the gut depends on the concentrations of recipient and donor bacteria and on their fertility. The main determining factors for the former are flow rate, concentration of limiting substrate, growth rates, adhesion, contamination and segregation and of the latter plasmid content, growth phase, and ecological conditions. These factors have to be measured with experimental models, and included in mathematical models, to estimate their relative incidence.