Is it necessary to include both Dr. as a prefix and credentials (M.D., D.O.) as a suffix? In my opinion, no. It’s repetitive. It should be listed as Dr. John Doe or John Doe, M.D, and I prefer the later.
Specifically, on a CV, the later looks most professional and then add any additional credentials, such as F.A.C.S. or F.A.A.P. as appropriate. I think it’s good to list these, but don’t get too lengthy. Just one set is sufficient. Additionally, don’t list any bachelor or master degrees in your title, as the reader will see them later on in the CV. Do list any doctorate level degrees in the title, such as: John Doe, MD, PhD.
As to whether or not to put a period after each letter, grammar would say to include them, but I think it’s up to personal style. Personally, I think it’s easier on the eyes with less punctuation.
Ultimately, you have to decide how you feel most comfortable listing your title. Punctuation or none, how much to list, etc. I beg you though…please don’t use Dr. and MD and if you are the lucky person to help a resident put together their first CV, give them the inside scoop on this. 🙂