MEET OUR TEAM

Karen-Whitley Bishop, PA-C – Board certified as a Physician Assistant Karen has been a part of the team since opening in 2013. She joined us after working for more than 20 years in the emergency department at HealthAlliance Leominster and Burbank Hospitals. She previously was a research assistance at Massachusetts Eye and Ear Infirmary in Boston.

Karen received her Master’s in Physician Assistant Studies from Mount Holyoke College in South Hadley. She is a resident of Rutland.

Michael Cobill, PA-C – Board Certified as a Physician Assistant, Mike joined our team in 2021.

Before joining our team Mike worked primarily in the Emergency Department at Mount Auburn Hospital in Cambridge, where he became the Chief PA for the department. His prior experience also includes working per diem at the North Shore Medical Center Emergency Department in Salem, the Brigham and Women’s Faulkner Emergency Department in Boston, as well as in the urgent care setting in both the Boston and Springfield areas.

A graduate of the University of Connecticut, he received his Master’s in Physician Assistant Studies at Northeastern University in 2013. He has undergone training in Basic Life Support, Advanced Cardiac Life Support, Advanced Trauma Life Support, and Pediatric Advanced Life Support. Mike is a resident of Longmeadow.

Bob Cooke, PA-C – Board Certified as a Physician Assistant, Bob has been a member of the team since 2019.

In joining our team Bob brings with him 25+ years of experience. A graduate of the Northeastern University PA Program in 1996, he has worked in the fields of cardiology, primary care medicine, as well as emergency and urgent care medicine. Bob has over 10 years of experience working in the ER having worked primarily in Leominster with the Wachusett Emergency Physicians. He also spent time working in the emergency room at Nantucket Cottage Hospital, Sturdy Memorial Hospital in Attleboro, and Saint Vincent Hospital in Worcester.

Karl Hirschegger, PA-C – Karl is a board-certified physician assistant that joined our team in 2023.

He brings with him a breadth of knowledge in critical care and emergency medicine. After graduating from the PA program at Bay Path University in 2015 Karl began working at Berkshire Medical Center in the emergency room. After four years in the ER Karl transitioned to working at Cooley Dickinson Hospital as a Critical Care PA in the ICU, where he continues to work full time. In the ICU he cares for the sickest patients in the hospital and performs a wide range of complex procedures. Since joining our team, he has enjoyed contributing to the continuum of patient care by applying his broad knowledge to the urgent care setting.

Karl received his undergraduate degree from Assumption University where he majored in Biology and Philosophy with a minor in Psychology. He currently resides in Chester with his wife and two children.

Karl is also one of only about sixty licensed falconers in the state of Massachusetts.

Donald P. Jackel, DO. FACEP – Board Certified in Emergency Medicine and a doctor of Osteopathic Medicine, Don joined our team in 2013 from Wachusett Emergency Physicians, PC (WEP), UMASS Memorial Health Alliance Hospitals.

He has served as Department Chair and Clinical Director of Wachusett Emergency Physicians in Leominster and is affiliated with the emergency department at Saint Vincent Hospital in Worcester.

A Magna Cum Laude graduate of the University of Southern Maine, Don received his doctorate from the University of New England’s College of Osteopathic Medicine. He then conducted his internship at UMASS Medical Center, where he also completed his residency in Coordinated Emergency Medicine.

He is resident of Worcester.

Donald P. Jackel, DO. FACEP – Board Certified in Emergency Medicine and a doctor of Osteopathic Medicine, Don joined our team in 2013 from Wachusett Emergency Physicians, PC (WEP), UMASS Memorial Health Alliance Hospitals.

He has served as Department Chair and Clinical Director of Wachusett Emergency Physicians in Leominster and is affiliated with the emergency department at Saint Vincent Hospital in Worcester.

A Magna Cum Laude graduate of the University of Southern Maine, Don received his doctorate from the University of New England’s College of Osteopathic Medicine. He then conducted his internship at UMASS Medical Center, where he also completed his residency in Coordinated Emergency Medicine.

He is resident of Worcester.

Mary Beth (Reidy) Laliberte, PA-C – Board Certified as a Physician Assistant, Mary Beth joined our team in 2013 from Wing Emergency Physicians.

Prior to becoming an integral member of our team Marybeth worked as a Physician Assistant at Wachusett Emergency Physicians in Leominster as well as in the Baystate Emergency Department. Before her time working in the ER she worked in the Department of Cardiology at the University of Massachusetts-Wing Memorial Hospital; Hampden County Sheriff’s Department, Springfield; and Department of Cardiothoracic Surgery, Veterans Administration Hospital, West Roxbury.

Mary Beth has received a Physician Assistant Certificate and Master of Health Professions degree from Northeastern University in Boston. A Frances Perkins Fellow at Mount Holyoke in South Hadley, she also received a bachelor of science nursing degree, magna cum laude, from Elms College in Chicopee.

William O’Callahan Jr., M.D. – Board Certified in Emergency Medicine, Bill joined our team in 2022 from Newton-Wellsley Hospital ER.

After attending Harvard University during his undergraduate years, Bill then attended the University of Massachusetts Medical School where he proceeded to do his Emergency Medicine residency and became the Chief Resident in his final year.

Following his residency Dr. O’Callahan went on to practice as a Flight Physician for two years, spent a year practicing Emergency Medicine at Kaiser Permanente Hospital in Honolulu, and then went on to act as an emergency medicine clinical instructor at Boston University School of Medicine as well as at the former Boston City Hospital.

Dr. O’Callahan continues to work clinically in the ER but has joined our team and brings with him 30+ years of emergency medicine experience.

When Bill is not working in the clinic or the emergency room you are likely to find him on his boat, deep sea fishing.