Dr. Catherine Liu is a physician who specializes in the prevention and treatment of infectious diseases that affect patients with weakened immune systems, particularly those with cancer and recipients of hematopoietic stem cell transplants, also known as blood stem cell transplants. As director of the antimicrobial stewardship program at Fred Hutchinson Cancer Center, her goal is to optimize antibiotic use to prevent the emergence and spread of drug-resistant microbes and achieve the best clinical outcomes for patients. She also directs the outpatient parenteral antimicrobial therapy program at Fred Hutch, which manages patients transitioning from hospitalization to an outpatient setting who require intravenous antibiotics. In these roles, she develops guidelines to promote the appropriate use of antibiotics and leads a multidisciplinary team of advanced practice providers and pharmacists to assist clinicians with antimicrobial dosing and selection as well as monitoring for medication side effects.