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Digestive Health Specialists of Mobile

Located in the heart of Springhill

Our highly skilled team of doctors and staff treat a variety of digestive disorders.  Our proximity to  Springhill Medical Center gives us the added support and technology to provide the best care for you.


Susan B. Fleet  MD

graduated magna cum lade from West Virginia University with a BA in biology.  She obtained her medical degree from the West Virginia University School of Medicine.  She completed an internship and residency in Internal Medicine and a fellowship in Gastroenterology at the University of Florida Shands Teaching Hospital in Gainesville, Florida.

Dr. Fleet was a National Merit Finalist in high school, she was elected to the Phi Beta Kappa Honor Society.  She was elected the Phi Kappa Phi Honor Society, and Alpha Omega Alpha Medical Honor Society in college.

Dr. Fleet is married to a retired neurologist, Dr. William S. Fleet.  She has 1 son, Alexander, who graduated from Auburn University in computer science and is currently studying pre-med.  She enjoys walking, reading, spending time with her family, and going to the beach.

A notable fact about Dr. Fleet is that she was the first female gastroenterology fellow at the University of Florida, and she was the only female gastroenterologist in private practice in Mobile for over 25 years.

Panayiotis Grevenitis  MD

graduated from the University of South Alabama College of Medicine in 2010.  He then completed his internal medicine residency followed by gastroenterology and hepatology fellowship at the Medical University of South Carolina in 2016.  He moved back to his hometown of Mobile to be closer to his family. His wife is a pediatrician, and they have two young daughters.  He is an avid sports fan and loves to play golf.


Dr. Grevenitis specializes in general gastroenterology and hepatology, including: Esophageal Disorders, GERD, Liver Disorders, Pancreaticobiliary Tract Disorders, Irritable Bowel Syndrome, Inflammatory Bowel Disease, and Celiac Disease. 


Michael Sanders  MD, FASGE

has over 23 years of experience in the medical field. Notably, he has extensive experience with Pancreatic Disease, Esophageal Disorders, and Gastrointestinal Disorders.  He graduated from University of South Alabama College of Medicine medical school.

Cody B. Barnett MD, FACG

graduated from Louisiana State University, and he is originally from south Louisiana and attended LSU in Baton Rouge.  He graduated cum laude in Microbiology in 1996 and completed medical school at LSUHSC-Shreveport in 2001.  He subsequently moved to Mobile, Alabama and completed an internal medicine residency and gastroenterology fellowship in 2007.  

Dr. Barnett's fellows and memberships include:

- ABIM Certified, Gastroenterology

- Fellow, American College of Gastroenterology

- Member, American Gastroenterology Association

- Member, American Society of Gastrointestinal Endoscopy

- Member, Alabama Gastroenterology Society

- Member, Mobile Medical Society

Dr. Barnett and his wife have been residents of Mobile for over 20 years now.  They have 2 children who were both born in Mobile and attend St Paul's Episcopal School.   When he is not working, he enjoys spending time with his family.  Outside of his involvement with his kid's school and extracurricular activities, he and his wife take frequent trips to the beach and also like to go see live music.


A notable fact about Dr. Barnett is that his wife always tells him how "level-headed" he is by not overreacting to certain situations and staying calm.



Jonathan D. Siegel MD, FACG

received his undergraduate degree from  University of Florida. He completed Medical School and Family and Internal Medicine Residency at Eastern Virginia Medical School .  He received his Gastroenterology Fellowship training at University of South Alabama.

Dr. Siegel is married to his wife, Danielle, and they have three children.  They moved to Mobile in 2003 for the Gastroenterology Fellowship training at University of South Alabama.  His son Zachary and his wife Karen are teachers at an international school in Beijing, China.  Middle son, Benjamin, attends Boston University working toward his masters in biomedical engineering.  His youngest, Noah, attends the University of Michigan.  Dr. Siegel loves running with his dog. He also enjoys offshore fishing with his boys, hiking the red rocks of Sedona, Arizona, and outdoor movie nights with his wife.

A notable fact about Dr. Siegel is that he believes all patients need medical care, but many seek something else.  It may be reassurance, it may be support through a difficult time, it may be the kindness of empathy, and he relentlessly strives to identify and provide for that need.


Alison Holland  CRNP

has over 10 years of diverse medical experience.  Subsequent to earning her Nurse Practitioners license, she graduated from the University of Mobile with her Bachelors of Science in Nursing.  She later graduated with honors from the University of South Alabama where she received her Masters of Science in Nursing.  Alison holds certifications as an Acute Care Nurse Practitioner. 


Alison and her husband, Jeff, have two children, Lainey and Cole, and 3 grandchildren. She loves spending her free time hunting, crafting, and relaxing on the river with her family.


Roxanna Hare  PA-C

graduated from the University of Alabama with a Bachelors in Psychology, and then received her Masters of Health Sciences in Physician Assistant Studies from the University of South Alabama. She was elected to Alpha Eta Honors Society during her time at USA.  She is also a member of the American College of Gastroenterology.

Roxanna is from Grove Hill, Alabama and now lives in Fairhope. She has a yellow lab named Winston. She and her fiancé, Michael, will be getting married in February of 2024. She loves iced coffee, walks with Winston, going to the beach, and Alabama football. 


Jessica Kantrales  PA-C

has over five years of gastroenterology experience.  Prior to earning her Masters of Health Sciences in Physician Assistant studies from the University of South Alabama, she graduated with a Bachelors in Radiologic Sciences and worked as a radiologic technologist for six years. She is a member of the American College of Gastroenterology.

Jessica is from Leakesville, Mississippi and now lives in Mobile with her husband, Peter, and their border collie, Cooper. She enjoys hiking, reading, walking Cooper, and spending time with family and friends.


Stacy Lambert  PA-C

has 16 years of medical experience.  Subsequent to receiving her Masters of  Health Science in Physician Assistant Studies from the University of South Alabama, she graduated from the University of Alabama with a Bachelors of Science in Athletic Training.  Stacy is a member of the American College of Gastroenterology and the American Academy of Physician Assistants.


Stacy and her husband, Brake, live in Mobile with their four children.  She loves to travel, Orange Theory Fitness, and spending time with her kids.


Brooke O'Sullivan CRNP

graduated from the University of South Alabama with a Bachelors in Nursing and worked as a registered nurse for eight years before returning to complete her Masters of Science in Nursing at University of Mobile.  She worked as an endoscopy nurse four of those years. 

Brooke and her husband, Kevin, live in Daphne, Alabama.  She is originally from Gautier, Mississippi.  She loves spending time with family and friends, being an aunt, going to the beach, F45 workout classes, and Alabama football.


Chelsea Sigler CRNP

graduated Cum Laude from the University of Alabama where she earned her Bachelor of Science degree in Nursing.  Subsequent to earning her Nurse Practitioner's license, she graduated from the University of South Alabama where she received her Masters of Science in Nursing.  

Prior to becoming an NP, Chelsea worked as a registered nurse for nine years.  Four of those years, she worked as an endoscopy nurse for the doctors.


Chelsea and her husband, Colin, have a Goldendoodle named Penny.  She and Colin grew up in Mobile and come from large families that live in the area as well.  She enjoys walks with Penny, cooking, watching Alabama football, and spending time with her friends and family.


Katie White PA-C

graduated from the University of South Alabama's Physician Assistant Program in August 2021. Prior to this, she received her Bachelors in Biomedical Science with a minor in Chemistry and Forensic Science at the University of South Alabama. During her time at USA, she participated in research on HPV with Mitchell Cancer Institute. She is currently a member of the ACG.


Katie and her husband, Harrison, live in Mobile with their 2 dogs and 2 cats. She is from Jackson, Alabama and is proud to serve patients from her hometown.  She enjoys reading, watching football, hunting, and spending time with family.

Nicole Young CRNP

graduated from Troy University in 2014 with a Master of Science in Nursing, specializing in Family Practice. She received her Bachelor of Science in Nursing from the University of South Alabama in 2007. Prior to becoming a nurse practitioner, she worked as an ICU nurse where she served as captain of the code team. She was elected to the Phi Kappa Phi and Sigma Theta Tau Honor Societies. She is a member of the American Academy of Nurse Practitioners, Bay Area Nurse Practitioner Association, and the American College of Gastroenterology.


Nicole is a native of Mobile where she lives with her husband, Darryl, and three children. She enjoys spending time with her family and friends, running, reading, going to the beach, and watching Alabama Football.

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