Methods and antibody compositions that displace mannose from the binding pocket of fimbrial adhesin FimH of enterobacteria, including uropathogenic E. coli, Klebsiella oxytoca, or Klebsiella pneumoniae, can be used to disrupt or prevent the attachment of a single layer of bacteria to a mannose-coated surface, or to disrupt or prevent the formation of a multilayer biofilm. The antibody compositions of the invention can thus be used in methods to inhibit, prevent, or reverse the colonization of a surface with enterobacteria that express the bacterial Type 1 fimbrial adhesin FimH, to inhibit or prevent infection of a cell by enterobacteria that express the bacterial Type 1 fimbrial adhesin FimH, such as, for example, uropathogenic E. coli, to treat a bacterial infection in subject in need thereof, and to treat or prevent inflammatory bowel disease (IBD), among other uses.
