Highly prevalent cargo genes of F plasmids harbored in pathogenic Escherichia coli

Analysis of prevalent orthogroups (OGs) in a collection of F plasmids from extraintestinal Escherichia coli ST131 isolates has led to the identification of two groups of previously uncharacterized cargo genes that may be widely distributed among F plasmids of pathogenic E. coli. Group 1 comprises four OGs whose encoded proteins are predicted to be involved in transport-related functions. The corresponding genes cluster with other genes associated with metabolism and are highly prevalent in extraintestinal ST131 isolates. Group 2 comprises several OGs whose encoded proteins currently have unknown functions. These OGs are present in a large proportion of F plasmids from both intestinal and extraintestinal E. coli isolates. The corresponding genes cluster within an F-plasmid region that also contains genes involved in DNA metabolism, suggesting that the proteins encoded by these newly identified OGs may likewise contribute to F-plasmid DNA biology. Characterizing the functions of these newly identified proteins may improve our understanding of the contribution of F plasmid to E. coli virulence and reveal novel targets for antimicrobial intervention, either by limiting F-plasmid dissemination among multidrug-resistant (MDR) E. coli strains or by directly targeting plasmid-carrying bacteria.