Color-enhanced TEM of an epithelial cell infected with Chlamydia trachomatis. A large inclusion of body containing Chlamydia occupies most of the volume of the cell. 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 like spores when released into the host. Disorders caused by Chlamydia trachomatis include chlamydia, trachoma, lymphogranuloma venereum, nongonococcal urethritis, cervicitis, salpingitis, pelvic inflammatory disease, and pneumonia. Magnification 1100x at 35mm.