Disclosed herein is an attenuated Acinetobacter baumannii comprising an expression vector comprising a nucleic acid encoding the ABUW_1645 protein or a variant thereof. Disclosed herein are methods of treating or preventing colonization, infection, or disease by an Acinetobacter baumannii microbe, the method comprising administering a clinically effective dose of the attenuated Acinetobacter baumannii to a subject in need thereof, wherein the attenuated Acinetobacter baumannii comprises an expression vector expressing the ABUW_1645 protein or variants thereof.
