The present disclosure provides MrkA binding proteins, e.g., antibodies or antigen binding fragments thereof that bind to MrkA and induce opsonophagocytic killing of Klebsiella (e.g., Klebsiella pneumoniae). The present disclosure also provides methods of reducing Klebsiella (e.g., Klebsiella pneumoniae) or treating or preventing Klebsiella (e.g., Klebsiella pneumoniae) infection in a subject comprising administering MrkA binding proteins, e.g., antibodies or antigen-binding fragments thereof, MrkA polypeptides, immunogenic fragments thereof, or polynucleotides encoding MrkA or immunogenic fragments thereof to the subject.
