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Our Providers

Samantha Bacchus, MD

Dr. Samantha Bacchus joined us in 2022 with over 20 years of Pediatric Medicine, practicing in New Jersey and Pennsylvania. Studying her undergraduate at Rutgers University, she completed her Doctor of Medicine at the Robert Wood Johnson Medical School and completed her residency at Dupont/Jefferson. Her interests include asthma and nutrition and female adolescence.

She is an active member of GAWN, the Gainesville Area Women’s Network, and she enjoys cooking, tennis and interior design. Dr. Bacchus is also an advocate for Ovarian Cancer with 2 Non-Profit Organizations, OCRA and Sandy Rollman. We are so fortunate to have Dr. Bacchus as a part of our team here at Alliance.


Rachel Coleman, MD

Dr. Rachel Coleman joined us in 2022 with over 16 years of Pediatric experience, working the last 10 years at UF Pediatrics at Tower Square, taking care of the children of Gainesville. She continues to care for our community here at Alliance Pediatrics and her fourth trimester practice, Honeybee Pediatrics.

In her downtime, she spends time with her husband and three children, and enjoys reading, traveling and exercising. Her special areas of medical interests are fourth trimester care and breastfeeding medicine.


Katheryn Sarantos, MD

Katheryn Sarantos, MD

Dr. Katheryn Sarantos has always had a strong passion for helping others. Coupled with her affinity for medicine, she has been serving the Gainesville community for almost 20 years. She began her career as a medical student at the University of Florida, where she also completed her residency, focusing on Pediatrics. Dr. Kathy, as her patients call her, really focuses on teaching both parents and patients the importance of nutrition and exercise. She strives to instill in her patients the importance of living a healthy lifestyle, both spiritual and physical.

“We get involved in their families, their parents, and their lifestyle. As we minister to the kids about healthy eating habits, we know that we’re ministering to their parents also. So that becomes our focus, the family as a whole.”


Olga Mas, MD

Olga Mas, MD

While she has lived in the Gainesville community for almost two decades, Dr. Olga Mas brings to the practice a diverse cultural background. She provides a warm familiarity and common understanding to the diverse families she cares for.  Dr. Mas strives to provide the best care for her patients, and does all she can to help them. She completed her medical degree at Universidad Central del Este in the Dominican Republic and her residency at Arnold Palmer Hospital for Women and Children in Orlando, concentrating in Pediatrics.

“Our partnership is solidified by our common faith in God and our commitment to provide good care for our patients.”


Michelle Massias, MD

Michelle Massias, MD

Dr. Michelle Massias became a Gator while working towards her undergraduate degree. She then ventured to NYC in 2003, where she obtained her medical degree from Ross University. She returned to Gator country to do her Pediatric Residency. She has a passion for fighting the epidemic of obesity in children and adolescence and consistently infuses the importance of daily decisions in creating a healthy lifestyle. While there are no overnight success stories, she has committed herself to continuing to encourage her patients to become the person they were created to be. Dr. Massias also has a great passion for international medical missions and this is evident by her various trips to remote parts of the world. When asked what part of pediatrics she loves the most, she said:

“I love the age spectrum; from the newborn period helping moms with breastfeeding and other common newborn issues, to the fun yet trying toddler years, to our adolescents where I feel we as pediatricians can have such a positive impact during one of the most challenging times of their lives. It’s a journey and I feel blessed to be a part of it.”


Ginny Shreve, ARNP

Ginny Shreve, ARNP

Virginia Shreve, better known as Ginny, has been part of the Alliance team since 2000. She completed her ARNP education at the University of Florida, specializing in Pediatrics. She has a strong background in ADHD and behavioral issues, while also maintaining an interest in Autism spectrum disorders. She brings to the practice a strong work ethic along with a passion for creating lasting relationships with the families the she cares for.

“I feel very fortunate and blessed to have a job that I really love and enjoy. It is so much fun to see children grow and develop through the years. I like to be able to help parents or caregivers make the best decisions for their children by educating them and listening to their concerns.”