The present invention relates to an isolated nucleic acid molecule encoding an antigen, a vector comprising such nucleic acid molecule and a host cell comprising such vector. Furthermore, the invention provides antigens from Klebsiella species, fragments and variants thereof, a process for producing such antigens, and a process for producing cells expressing such antigens. Moreover, the present invention provides antibodies binding to such antigen, hybridoma cells producing such antibodies, methods for producing such antibodies, a pharmaceutical composition comprising such nucleic acid molecule, antigen, vector or antibody, the use of such nucleic acid molecule, antigen, vector or antibody for the preparation of a pharmaceutical composition, methods for identifying an antagonist capable of binding such antigen or of inhibiting the interaction activity of such antigen, methods for diagnosis or for treatment or prevention of an infection. More specifically, such antigens are associated with nosocomial bacterial infections or infection by Klebsiella pneumoniae.
