The Orangeburg-Calhoun Regional Hospital shall be governed by a board of trustees to be composed of seventeen members, twelve of whom shall be residents of Orangeburg County who shall be appointed by the Governor upon the recommendation of the governing body of Orangeburg County and three of whom shall be residents of Calhoun County who shall be appointed by the Governor upon the recommendation of the governing body of Calhoun County. The Chief of Staff and the chairman of the executive committee of the hospital's medical staff shall be ex officio members of the Board. Except as otherwise provided in this article, the terms of the appointed members shall be for two years and until their successors are appointed and qualify, vacancies shall be filled in the manner of the original appointment for the unexpired portion of the term only. Appointments shall be filed in the offices of the clerks of court for Orangeburg and Calhoun Counties. The board shall annually elect a chairman, vice-chairman, a secretary and such other officers as it deems necessary.