Methods of treating bacterial infection in immunocompromised subjects and subjects with one or more underlying malignancies include administering a combination of meropenem and vaborbactam to the subject. Suitable subjects to be treated can include a subject with a history of ongoing leukemia or lymphoma, a subject that has had an organ transplant, stem cell transplant, bone marrow transplant, or splenectomy, a subject receiving immunosuppressive medications, a subject receiving bone marrow ablative chemotherapy, a subject with neutropenia and subject suffering from or having suffered from a malignancy.