Described are a therapeutic monoclonal antibody specific for the Type Six Secretion System (T6SS) needle protein of Acinetobacter baumannii (A. baumannii) and methods of use. Specifically, the antibody specifically binds to hemolysin co-regulated protein (Hep). Further disclosed are methods of using an anti-Hep antibody for detecting A. baumannii in a sample as well as a mutant A. baumannii strain comprising a deletion or mutation in its genome such that said deletion or mutation interrupts the proper translation of its hep protein.
