A cell, isolated nucleic acid, vector, isolated polypeptide, and method of treating a bacterial infection are provided. The cell includes a modified Acinetobacter baumannii cell having a mutation in an A. baumannii gene selected from a mutation that occurs when generating mutations in A. baumannii using transposon mutagenesis. The isolated nucleic acid includes a sequence expressing a lpsB, mffT, or GctA polypeptide comprising at least one nucleic acid mutation. The vector includes the isolated nucleic acid. The isolated polypeptide includes a lpsB, mffT, or GctA polypeptide comprising at least one nucleic acid mutation. The method of treating a bacterial infection includes administering to a subject an effective amount of an Acinetobacter baumannii composition including modified Acinetobacter baumannii cell.
