Chlamydia trachomatis

Chlamydia trachomatis () is a Gram-negative, anaerobic bacterium responsible for chlamydia and trachoma. C. trachomatis exists in two forms, an extracellular infectious elementary body (EB) and an intracellular non-infectious reticulate body (RB). The EB attaches to host cells and enter the cell using effector proteins, where it transforms into the metabolically active RB. Inside the cell, RBs rapidly replicate before transitioning back to EBs, which are then released to infect new host cells. The earliest description of C. trachomatis was in 1907 by Stanislaus von Prowazek and Ludwig Halberstädter as a protozoan. It was later thought to be a virus due to its small size and inability to grow in laboratories. It was not until 1966 when it was discovered as a bacterium by electron microscopy after its internal structures were visually observed. There are currently 18 serovars of C. trachomatis, each associated with specific diseases affecting mucosal cells in genital tracts and ocular systems. Infections are often asymptomatic, but can lead to severe complications such as pelvic inflammatory disease in women and epididymitis in men. The bacterium also causes urethritis, conjunctivitis, and lymphogranuloma venereum in both sexes. C. trachomatis genitourinary infections are diagnosed more frequently in women than in men, with the highest prevalence occurring in females aged 15 to 19 years of age. Infants born from mothers with active chlamydia infections have a pulmonary infection rate that is less than 10%. Globally, approximately 84 million people are affected by C. trachomatis eye infections, with 8 million cases resulting in blindness. C. trachomatis is the leading infectious cause of blindness and the most common sexually transmitted bacterium. The impact of C. trachomatis on human health has been driving vaccine research since its discovery. Currently, no vaccines are available, largely due to the complexity of the immunological pathways involved in...