C. trachomatis is a Gram-negative bacteria, and a leading cause of sexually transmitted disease worldwide. It is also the leading cause of preventable blindness (caused by a chlamydia infection called trachoma). C. trachomatis is also one of the major causes of pelvic inflammatory disease (PID) and infertility in women.
Chlamydia is transmitted through infected secretions only. It infects mainly mucosal membranes, such as the cervix, rectum, urethra, throat, and conjunctiva.