Headshot of a smiling man with light skin tone and a grey beard wearing an open-collar, light blue dress shirt under a dark blue suit jacket against a blurred outdoor background

Keith Hazleton, MD, PhD

Attending Physician
Assistant Professor of Clinical Pediatrics, Keck School of Medicine of USC

Keith Hazleton, MD, PhD, is an Attending Physician of Pediatric Gastroenterology, Hepatology and Nutrition and Assistant Professor of Clinical Pediatrics, Keck School of Medicine of USC. He received is MD and his PhD from the Albert Einstein College of Medicine and completed his pediatrics specialty training at the Children's Hospital Colorado/University of Colorado. He has joined the liver and intestinal transplant team at CHLA and is researcher at the Saban Research Institute.

His research has focused on how what we eat can affect the intestinal infection caused by C. difficile as part of Dr. Catherine Lozupone's lab at University of Colorado. His work has shown that dietary fat and fiber can affect the severity of infection and led to a clinical trial using a low-fat, high-fiber diet to prevent C. difficile infection. His work is currently funded by the National Institutes of Health and previously received funding from the Cystic Fibrosis Foundation.


Medical School

The Albert Einstein College of Medicine


Children's Hospital Colorado/University of Colorado


Children's Hospital Colorado/University of Colorado


Children's Hospital Colorado/University of Colorado



American Board of Pediatrics - General Pediatrics; Gastroenterology; Transplant Hepatology

Professional Memberships

North American Society for Pediatric Gastroenterology, Hepatology & Nutrition
American Association for the Study of Liver Diseases
Society of Pediatric Liver Transplantation


Alpha Omega Alpha Medical Honor Society


Hazleton KZ, Martin CG, Orlicky DJ, Arnolds KL, Nusbacher NM, Moreno-Huizar N, Armstrong M, Reisdorph N, Lozupone CA. Dietary fat promotes antibiotic-induced Clostridioides difficile mortality in mice. NPJ Biofilms Microbiomes. 2022 Apr 1;8(1):15. doi: 10.1038/s41522-022-00276-1. PMID: 35365681

Kriss M, Hazleton KZ, Nusbacher NM, Martin CG, Lozupone CA. Low diversity gut microbiota dysbiosis: drivers, functional implications and recovery. Curr Opin Microbiol. 2018 Aug;44:34-40. doi: 10.1016/j.mib.2018.07.003. Epub 2018 Jul 20. PMID: 30036705

Hazleton KZ, Ho MC, Cassera MB, Clinch K, Crump DR, Rosario I Jr, Merino EF, Almo SC, Tyler PC, Schramm VL. Acyclic immucillin phosphonates: second-generation inhibitors of Plasmodium falciparum hypoxanthine-guanine-xanthine phosphoribosyltransferase. Chem Biol. 2012 Jun 22;19(6):721-30. doi: 10.1016/j.chembiol.2012.04.012. PMID: 22726686


Research Interests

  • C. difficile infection
  • Gut microbiome
  • Dietary therapy
  • Liver disease
Division of Gastroenterology, Hepatology and Nutrition

4650 Sunset Blvd.
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United States