Vaccination with Acinetobacter baumannii adhesin Abp2D provides protection against catheter-associated urinary tract infection

Catheter-associated urinary tract infections (CAUTIs) contribute greatly to the burden of healthcare associated infections. Acinetobacter baumannii is a Gram-negative bacterium with high levels of antibiotic resistance that is of increasing concern as a CAUTI pathogen. A. baumannii expresses fibrinogen-binding adhesins (Abp1D and Abp2D) that mediate colonization and biofilm formation on catheters, which become coated with fibrinogen upon insertion. We developed a protein subunit vaccine against Abp1D(RBD) and Abp2D(RBD) and showed that vaccination significantly reduced bladder bacterial titers in a mouse model of CAUTI. We then determined that immunity to Abp2D(RBD) alone was sufficient for protection. Mechanistically, we defined the B cell response to Abp2D(RBD) vaccination and demonstrated that immunity was transferrable to naïve mice through passive immunization with Abp2D(RBD)-immune sera. This work represents a novel strategy in the prevention of A. baumannii CAUTI and has an important role to play in the global fight against antimicrobial resistance.