Chlamydia trachomatis. Coloured Transmission Electron Micrograph (TEM) showing two Chlamydia trachomatis bacteria. These spherical, virus-like bacteria (pink) parasitise human cells in order to reproduce. Chlamydia trachomatis causes various types of genital, eye, and lymph node infections. It is responsible for the sexually-transmitted diseases: lymphogranuloma venereum (enlarged lymph glands with skin ulcers), and non-specific urethritis (NSU) affecting the urogenital tract. It also causes trachoma eye disease, a serious cause of blindness. Treatment is effective with antibiotic drugs such as erythromycin. Magnification: x40, 000 at 6x4.5cm size.