Chlamydia trachomatis

It is a gram-negative bacterium with a unique biphasic developmental cycle. It possesses an elementary body (EB), the infectious form, and a reticulate body (RB) that replicates within host cells. The bacterium lacks peptidoglycan in its cell wall and relies on host cell machinery for energy. Chlamydia trachomatis enters host cells via endocytosis, forming an inclusion where it replicates. The bacterium can evade the host immune response by inhibiting phagolysosomal fusion. This intracellular lifestyle contributes to chronic infections and tissue damage.

Chlamydia trachomatis infections can be asymptomatic or present with a range of clinical symptoms. In women, genital infections may lead to urethritis, cervicitis, or pelvic inflammatory disease (PID). Men can experience urethritis. Ocular infections with serotypes A-C cause trachoma, a leading cause of preventable blindness.

Laboratory diagnosis relies on nucleic acid amplification tests (NAATs) for detecting chlamydial DNA in clinical specimens. Serological assays detect antibodies but are less useful for acute diagnosis. Rapid diagnostic tests are available for point-of-care settings.