Fertility inhibition between conjugative plasmids

Abstract

Infections due to antibiotic-resistant enterobacteria are a worldwide cause of morbidity and mortality. Antibiotic resistance genes disseminate mostly by conjugative plasmids. Plasmid conjugation could be controlled by mechanisms naturally displayed by bacteria. Among them, fertility inhibition systems prevent conjugation of co-resident plasmids in donor cells. The study of interactions between conjugative systems could provide useful information to fight against antibiotic resistance dissemination. In this work, conjugation ability of IncW broad host range plasmids was analyzed in the presence of a representative set of co-resident plasmids. Two novel fertility inhibition systems against R388 conjugation were discovered in IncFI plasmid pOX38 and IncI1 plasmid R64. The precise mechanism of inhibition is being investigated. Interestingly, when R388 was substituted by a reduced synthetic version, these effects diminished two orders of magnitude, whereas the effects caused by other fertility inhibition systems encoded by IncP1α and IncX2 plasmids were maintained. This kind of knowledge could also be valuable for constructing bacterial computing devices employing conjugative plasmids as wires.