Our Team
Meet the Care team
Our Physicians
Dr. Sara Berg
Sara Rosenbaum Berg, MD FACP is a board-certified Internal Medicine physician who has been practicing with Northwestern since 2013.
Dr. Kate Petrungaro
Kate (Kathryn) M. Petrungaro, MD, FACP is a board-certified internal medicine physician who has been practicing with Northwestern Medicine since 2010.
Dr. Caroline Kalember
Caroline Kalember, MD is a board-certified Internal Medicine physician who has been practicing with Northwestern since 2012.
Dr. Mariamou Sims
Mariamou Sims, MD is a board-certified Internal Medicine physician who has been delivering compassionate, high-quality care to patients since 2007.
Our Staff
Meet the friendly faces you will see as you walk in the door
Christina, Practice Manager
Christina serves as the Practice Manager at Thrive Internal Medicine, bringing over 15 years of experience in healthcare administration. Much of her career was spent at Endeavor Health, where she built a strong foundation in patient care and operational leadership. She holds an MBA, which enhances her ability to bridge clinical support with strategic practice management. She is passionate about delivering compassionate, patient-centered care and her goal is to ensure the practice runs efficiently while fostering a warm, welcoming environment for both patients and staff.
Outside the office, Christina leads a vibrant, faith-filled life. She’s an avid gardener, enthusiastic traveler, and always exploring new whole food cuisine. A devoted member of The Salvation Army, her commitment to service is central to who she is. At home, she enjoys spending quality time with her husband, two children, and their beloved pets Chloe, a sweet Shih Tzu, and Tux, a charming tuxedo cat.
Andrea, Business Manager
Although I spent the first fifteen years of my career in public education, I transitioned to the healthcare field in 2019 and have found the opportunity to connect patients with skilled providers equally rewarding, nowhere more so than at Thrive. I am honored to participate in a patient experience that permits open and ongoing communication regarding individualized goals. I enjoy providing administrative support that allows our physicians to focus on caring for patients. When not working, I enjoy gluten-free baking, exercise, and time with my family.
Melissa, Medical Assistant
Before moving to Illinois to be with her lovely husband, Melissa worked in New York as a Medical Assistant for seven years. You can find her hiking, biking, or hanging with her three cats, a dog, and two hedgehogs in her free time. Thrive is an excellent practice for her as it satiates her desire to constantly learn and evolve in her field (thanks to working amongst a talented group of doctors and staff). Melissa loves going to work as the energy feels calm, welcoming, and filled with smiles.
Krystal, Medical Assistant
Before landing at Thrive, Krystal worked at Northwestern Hospital for eight years. She is a wife and mother to four humans (three boys and one Girl) and two fur babies (English Mastiff and Miniature Schnauzer). When she is not taking care of the craziness of dogs and kids, she loves to relax at home with her husband and crochet blankets. She is so happy to be a part of the Thrive family, as she is a proponent of prioritizing whole patient care in a friendly and skilled environment!
Brandie, Medical Assistant
Over 16+ years of experience as Medical Assistant in General Practice, Internal Medicine, Functional Medicine, Pediatrics, OB/GYN and Obesity Management. I am big on spending time with family and friends, which is what brought my wife and I to the Chicago area from Southern Arizona. My passion is music and caregiving. When I am not working in clinic I am outdoors, swimming, learning new instruments, building new projects and helping with good friends' Non-profit organization.
I recently joined the amazing Thrive team and love the mission and values of the providers that started this practice. They are kind, passionate, caring and are willing to go above and beyond for their patients, which is exactly what I want to be part of!
Questions?