Chlamydia trachomatis, an organism responsible for the most prevalent STD in the United States, is one of four bacterial species in the genus Chlamydia. C. trachomatis is a gram-negative bacterium. It is ovoid in shape and non- motile. The bacteria are non spore forming but the elementary bodies act as a spore when released into the host. The inclusion bodies of Chlamydia trachomatis were first described in 1942; the Chlamydia trachomatis agent was first cultured in the yolk sacs of eggs by Professor Tang Fei-fan et al in 1957.