Filamentous hemagglutinin adhesin FhaB limits A.baumannii biofilm formation.

Increased resistance and survival, as well as immune evasion, play a significant role in the pathogenicity of Acinetobacter baumannii. Here, we report on the adhesion of the bacterium to epithelial cells and formation of biofilm on abiotic surfaces. We identificed autotransporter (AT) genes that encode homologues (Fha-like) of the two-partner secretion system (TPS) in A.baumannii (ATCC19606) which we designate as FhaB (exoprotein) and FhaC (transporter) and demonstrate that these novel genes, are under the control of distinct regulatable promoters within either the same (FhaBC) or two distinct (FhaB and FhaC) cells. The expression of this gene in outer membrane protein (OM) showed them to be deficient in the adherence to A546 cells. FhaB is involved in hydrophobicity of A. baumannii ATCC19606 while FhaBC is associated with biofilm formation. The vaccinogenic potential of FHA-like proteins offers use of these targets as novel therapeutic strategies to limit A.baumannii associated morbidity and mortality.