first class. Upon the establishment of a consolidated local government in a county which contained a city of the first class, the mayor may, every four (4) years, appoint a purchasing agent for a term of four (4) years. The fiscal court of each county containing a city of the first class shall, every four (4) years, beginning in 1928, appoint a purchasing agent for a term of four (4) years, the term of the first purchasing agent to begin May 1, 1928.