Almost nothing, actually. Non-pathogenic laboratory strains of E. coli are missing several key gene families and operons required for host pathogenicity, and Ef

Almost nothing, actually. Non-pathogenic laboratory strains of E. coli are missing several key gene families and operons required for host pathogenicity, and Ef-Tu is a protein involved with translation, a basic process of the cell entirely unrelated to pathogenicity. No matter how the ancient EF-Tu performs, it won't suddenly result in complex and functionally unrelated mechanisms required for pathogenicity. There was essentially no human risk involved in this (or similar) experiments.