Enterobacter cloacae is part of the normal human gastrointestinal (GI) microbiota, however, it is also a serious opportunistic pathogen of humans, infecting immunocompromised individuals, the young, and the elderly. The pathogenic effects of E. cloacae become evident once colonization is established outside the GI tract. The mechanisms by which this colonization takes place are still mostly unknown. I am working on developing genetic tools to study these mechanisms. I am currently developing a protocol for generating markerless deletions of individual genes in the E. cloacae genome. This will allow for the study of specific genes and their effects on the colonization of E. cloacae outside of the GI tract.