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.本發明提供MrkA結合蛋白(例如，抗體或其抗原結合片段)，該等可結合至MrkA並誘導克雷伯氏菌(Klebsiella)(例如，克雷伯氏肺炎桿菌(Klebsiella pneumoniae))之調理吞噬殺滅(opsonophagocytic killing)。本發明亦提供減少個體中克雷伯氏菌(例如，克雷伯氏肺炎桿菌)或治療或預防克雷伯氏菌(例如，克雷伯氏肺炎桿菌)感染之方法，其包括向該個體投與MrkA結合蛋白(例如，抗體或其抗原結合片段)、MrkA多肽、其免疫原性片段或編碼MrkA或其免疫原性片段之多核苷酸。
