Type I pili, CsuA/B and FimA induce a protective immune response against Acinetobacter baumannii

Acinetobacter baumannii, a nosocomial pathogen, is considered as a common cause of hospital and community-acquired infections. Emerging multidrug-resistance in this pathogen followed by subsequent problems in treatment has been increasing to alarming levels that warrant investigation of new therapeutic approaches. One strategy to reduce antibiotic resistance is to use of vaccines. Although there is no vaccine currently in development for this pathogen, different attempts have been made to develop one. In this study, we used two different recombinant pilus proteins (CsuA/B and FimA) either singly or in combination to evaluate protective efficacy against A. baumannii in lethal and sub-lethal murine sepsis models. Active immunization with recombinant proteins in combination elicited high levels of IgG antibody after the first immunization and provided 62% (five of eight mice; p