SUMMARY. About 70-80% of serious bacterial infections are biofilm-mediated. Not only do biofilms provide an anchor and physical protection for bacterial cells, but antibiotic sensitivity differs between free living and sessile bacteria, with bacteria being less sensitive to antibiotics in the sessile state. One of the proteins comprising the biofilm matrix is the DNA binding protein HU and its close relatives. TRL1068, a patented human monoclonal antibody isolated by Trellis Bioscience, binds to HU and disrupts bacterial biofilms of wide origins causing the bacteria to revert to the antibiotic-sensitive state. Under SBIR funding, Trellis has discovered that TRL1068 is able to greatly enhance the efficacy of standard of care antibiotics to treat bacterial infection in multiple animal models; in the presence of TRL1068, reduction of CFUs over antibiotic alone can be improved by 2-3 orders of magnitude. Trellis has advanced TRL1068 through GMP manufacturing and preliminary toxicology with marked success, providing a clear path to filing an IND and initiation of human testing. In this Direct to Phase II STTR grant application, Trellis proposes to collaborate with academic and CRO scientists to extend the range of infections shown to be amenable to therapeutic improvement through the use of TRL1068. We will investigate three fields of investigation. One, we will explore the applicability of TRL1068 to infections of musculoskeletal implants; two, we will explore the effectiveness of inhaled TRL1068 for control of respiratory infections; and, three, we will investigate the relevance of in vitro models as screens for TRL1068 usefulness. By the time that TRL1068 has been tested for safety in humans, the data developed under this project will assist in the identification of the most appropriate Phase 2 clinical indications for this innovative and promising agent for infection control.