Osteopath's are Doctor's. And called D.O.s and addressed as Dr. Smith, or Morris, or whatever.
In fact their training is not much different these days from a M.D. If at all....
FWIW-
Yes, I should have said “M.D.” instead of doctor, to distinguish that degree from a Doctor of Osteopathy. My father’s family includes 11 graduates of Kirksville College of Osteopathic Medicine.